A novel in situ AuNPs synthesis by electrospinning technique

A novel in situ AuNPs synthesis by electrospinning technique | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A novel in situ AuNPs synthesis by electrospinning technique Cynthia Castro, Ana Arizmendi-Morquecho, Domingo García-Gutiérrez, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4277652/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract This study presents a new route for in situ synthesis of gold nanoparticles (AuNPs) and nanofibers using PEO-Gelatin as the supporting polymer via the electrospinning technique. Variation in the size and shape of the AuNPs significantly impacts their properties and applications, emphasizing the importance of precise methods for their synthesis. The proposed approach in this study aims to synthesize AuNPs and nanofibers simultaneously during the electrospinning process without the need for external reducing agents. This methodology offers significant advantages, such as conducting the reaction at room temperature while simultaneously synthesizing nanoparticles and fibers without requiring additional purification processes. The current work describes the synthesis conditions by adding chloroauric acid precursor (HAuCl 4 ▪3H 2 0) to the polymer solution for electrospinning and in situ reduction at a voltage of 14 kV. Additionally, the morphology of the fibers and particles was explored using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), revealing hexagonal particles with an average size of 12 nm. The presence of AuNPs was confirmed via UV-Vis spectroscopy through Surface Plasmon Resonance (SPR) at λ max 532 nm. Finally, it was found that the precursor reduction is dependent on pH, polymer functional groups, and applied voltage. AuNPs Nanofibers Electrospinning Gold reduction Metal nanoparticles Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction The synthesis methods for producing metallic nanoparticles include chemical reactions, physical methods, or biological methods, which can be divided into "Bottom Up" approaches, where nanoparticles are obtained from molecular or atomic level precursors, and "Top Down" methods, where nanoparticles are obtained by reducing the size of a metallic precursor.[ 1 ]. One of the most commonly used Bottom-Up methods involves the reduction of metallic precursors such as salts or acids. [ 2 ]. Thus, it has been proven that gold nanoparticles (AuNPs) with different sizes and shapes exhibit optical [ 3 ], [ 4 ], antioxidant [ 5 ], [ 6 ], catalytic [ 7 ], and unique chemical properties [ 8 ]. Due to these properties, they have been used in different technological applications, such as biosensor production, catalysis, and drug delivery, among others [ 9 ], [ 10 ], [ 11 ]. The synthesis of AuNPs with desired size and shape is of great importance in scientific research and practical applications, as small variations in size or shape can significantly impact various physical properties of nanostructures. Therefore, several methodologies have been used to adjust their size, such as: a) variations in precursor concentration [ 12 ]; b) molecular weight and type of stabilizing agent [ 13 ]; c) pH [ 14 ] and d) reducing agent [ 15 ]. There are several methods for synthesizing gold nanoparticles. One of the most common methods is the chemical reduction method, where gold ions (Au 3+ ) are reduced to gold atoms (Au 0 ) in solution using a reducing agent. Typical reducing agents include sodium borohydride (NaBH 4 ), hydrazine, and sodium citrate [ 16 ]. Sodium citrate is mainly used to obtain colloidal gold nanoparticles stabilized by citrate. Gold nanoparticles can also be synthesized using radiation, such as ultraviolet (UV) light or gamma radiation [ 17 ].Green methods commonly use extracts from plants or other natural sources rich in reducing compounds as reducing agents for the synthesis [ 18 ]. This method is considered more environmentally friendly and can lead to the formation of nanoparticles with unique properties. On the other hand, metallic nanoparticles tend to agglomerate or precipitate due to Van der Waals forces and high surface energy. Stabilizing agents, such as polymers, prevent this from happening and maintain a stable dispersion of these nanoparticles in solution [ 5 ], [ 19 ] [ 17 ]. In this sense, polymers provide a protective barrier that prevents agglomeration and sedimentation, maintaining a stable dispersion in solution. [ 20 ] An example is the study conducted by Bai et al. in 2007, where polyvinyl alcohol (PVA) nanofibers decorated with gold nanoparticles were produced without the need for stabilizing agents, owing to the presence of polyvinyl alcohol, which acts as such. Another example is demonstrated by Huang et al. in 2017, where they concluded that previously synthesized chitosan nanofibers act both as a reducing agent for AuNPs synthesis and as a stabilizer for the generated AuNPs, due to the reduction and chelation capacity of the amino groups in chitin [ 21 ]. Thus, it has been demonstrated that the stabilizing influence of polymers originates from their chemical nature, specifically from the functional groups [ 22 ]. For example, polyethylene oxide and bovine skin gelatin are good stabilizing agents in nanoparticle synthesis due to the presence of their functional groups, such as -NH 2 , -SH, and -COOH [ 23 ]. Polymer nanofibers obtained by electrospinning typically have diameters in the nanometer range (typically between 100 nm and 1 µm) [ 24 ]. Nanofibers can be generated from different polymers, thus exhibiting diverse physical properties and potential applications. Nanofibers often possess a high surface-to-volume ratio, making them suitable for applications where surface area is crucial, such as filtration, controlled drug release, and tissue engineering [ 25 ]. There are many different methods for producing nanofibers, including force spinning, meltdown, and electrospinning [ 26 ]. Electrospinning is one of the most widely used methods for generating nanofibers due to its simple setup, the ability to mass-produce continuous nanofibers from various synthetic and natural polymers, the capability to incorporate various types of biological molecules into them, as well as producing ultrafine fibers with controllable diameters, compositions, and orientations [ 27 ]. Combining nanofibers and metallic nanoparticles has led to hybrid structures with unique and diverse properties. Precious metals, such as gold, silver, platinum, etc., have been used to develop these materials [ 28 ]. Hybrids composed of polymer fibers and AuNPs have applications in catalysis, electronics, drug release devices, and sensors. AuNPs can be attached to functional nanofibers to create highly sensitive sensors for detecting specific molecules, such as biomarkers or contaminants in water and air [ 29 ]. For example, in 2017 E. Sapountzki et al. developed a glucose sensor based on nanofibers obtained through the electrospinning method. After synthesizing the fibers, they were decorated with enzymes anchored to AuNPs [ 11 ]. On the other hand, in 2020, Balashanmugam et al. synthesized AuNPs using a chemical method. They added them to a solution of PVA and PCL, which was then electrospun to obtain nanofibers for drug delivery purposes. The antioxidant and anticancer activities were studied in vitro. The results showed that the treatment with nanoparticles and nanofibers exhibited cytotoxicity on cancer cells through apoptosis but lower toxicity on normal cells compared to commercial drugs [ 30 ]. As shown in the previous examples, it has been reported that AuNPs can be synthesized and incorporated before or after the electrospinning process. Before electrospinning, the particles are synthesized using traditional chemical methods, and once obtained, they are incorporated into the solution that will be used during the process. The metallic precursor is added to the polymeric solution for synthesis after electrospinning. Once the nanofibers are synthesized, the nucleation of the AuNPs can occur using various methods such as gamma radiation, UV, or adding a reducing agent at a specific temperature [ 17 ], [ 31 ]. Therefore, this work aims to develop a new synthesis route for the simultaneous production of AuNPs and nanofibers without reducing agents, and this would allow clean nanoparticles to be obtained for subsequent applications in many areas. Currently, there are no reports of the proposed methodology, and compared to the methods described previously, the synthesis of AuNPs by the electrospinning technique is considered a method that presents several advantages: The reaction is carried out at room temperature, the yield of the NPs is high because it does not require any purification process, the synthesis of the NPs does not require any external reducing agent, the synthesis of the NPs and the fibers is carried out simultaneously without any previous or additional steps. 2. Experimental 2.1 Materials and Methods Poly(ethylene oxide) (PEO, Mw 600,000 g/mol), gelatin from porcin skin (gel strength 300, type A) were used for the synthesis of the fibers, gold (III) chloride hydrate (HAuCl 4 ▪3H 2 0, 99.99% trace metals basis), acetic acid glacial, Reagent Plus 99%, were purchased from Sigma-Aldrich and used as received without further purification. Polymer solutions were prepared with Milli-Q water. 2.2 Preparation of electrospinning solution A 7% (w/v) aqueous solution of PEO and gelatin using Milli-Q water was prepared by dissolving the polymers at 55°C and 40°C, respectively, and stirring for 5 hours. Then, the solutions were mixed at a 1:1 ratio of gelatin to PEO, and the gold precursor was added at a concentration of 0.10 mmol L − 1 dissolved in 400 µL of water-acetic acid solution with a ratio of 60:40. Similarly, Gelatin/PEO fibers were obtained without the Au precursor. 2.3 Fabrication of Gel/PEO- AuNPs electrospun nanofibrous membrane The electrospinning process was conducted using an Innovenso NS24 Electrospinning Machine. The solution was loaded into a 10 mL syringe equipped with a metal spinneret (21 G) and attached to a syringe pump (Innovenso IPS-12). The solution was ejected from the syringe at a rate of 0.4 mL h − 1 using a high voltage power supply set at 14 kV, positioned between the needle and a grounded collector covered with aluminum foil. The distance between the needle and the collector was 13 cm. Electrospinning took place at a temperature of 24°C. The formation of Gel/PEO- AuNPs by electrospinning is represented in scheme 1 2.4 Characterization of the AuNP/Gelatin-PEO electrospun nanofibrous membrane The FT-IR transmittance spectra were conducted using a single-beam Fourier transform infrared spectrometer (Nicolet iS10, USA). Spectra were measured in the spectral range of 4000–400 cm − 1 to analyze the chemical composition of the samples. Fiber diameters were determined using scanning electron microscopy (SEM), with images obtained using an SEM Jeol JSM-IT800. The average diameter and standard deviation were calculated from a sample of at least 100 fibers using Image J software. Transmission electron microscopy (TEM) images were acquired using an FEI, TITAN G2 80–300 instrument, equipped with High-Angle Annular Dark Field (HAADF), Bright Field (BF) and Annular Dark Field (ADF) detectors for Scanning Transmission Electron Microscopy (STEM) mode. During electrospinning, fibers containing AuNPs were collected on a TEM Cu-grid for subsequent analysis. The surface plasmon resonance (SPR) of gold nanoparticles at λ max 550 was characterized by scanning from 400 to 700 nm using a UV-Vis Spectrophotometer (Shimadzu Uv-1900i) with a 1 cm quartz cell. Approximately, 10 milligrams of the sample were weighed and placed in 3 mL of a water-acetic acid solution (60:40 ratio). The solution was then vortexed for 5 minutes before taking the readings (60:40 ratio). The solution was then vortexed for 5 minutes before taking the readings. 3. Results and Discussions 3.1 Preparation of Gelatin/PEO fibers with and without precursor Figure 1 a), SEM microscopy images of Gelatin/PEO composite fibers obtained by electrospinning from a pure water-based solution. The resulting fibers exhibited a smooth, cylindrical morphology without alignment and no bead-like defects along the resulting matrix. The average diameter of the fibers was 183 nm ± 22 compared to those developed by Thiago M. Righi et al. [ 32 ], who reported in 2012 the production of gelatin and PEO nanofibers in acetic acid-water, where they obtained diameters ranging from 160 nm to 1.2 microns. They added NaCl to improve the conductivity of the solution, obtaining smaller diameters and improving morphology; however, the dispersion was very high. In 2019, Nafise Amiri et al. developed fibers using the proposed polymers. They reported the impact on fiber diameter caused by the properties of the solution and working parameters, where they obtained diameters of 229.79 ± 41.45 to 308.66 ± 50.03 nm, closer to those reported in this work. However, they used acetic acid as a solvent, improving the conductivity of the solution and resulting in a defect-free diameter and morphology. [ 33 ] On the other hand, the impact on the morphology of the nanofibers from solutions prepared with the metallic precursor HAuCl 4 ·3H 2 O in water using 2% acetic acid was studied. Figure 1 b shows the Gelatin/PEO-HAuCl 4 ·3H 2 O fibers, where a reduction in fiber size was observed, resulting in an average diameter of 145 ± 17 nm. This phenomenon could be attributed to the increased conductivity of the Gel/PEO system due to the interaction between the precursor ions, which generates charged groups in the structure of the system [ 34 ], leading to stronger elongation forces in the polymer jet and thus resulting in a decrease in fiber diameter. Additionally, the formation of bright structures after the electrospinning process can be observed, which may indicate the formation of Au nanoparticles during the process; due to the presence of polymer as a stabilizing agent, the formation of AuNPs is presumed, however, more detail studies are in order to confirm such assertion. These were characterized by UV-Vis spectroscopy and TEM to determine their nature, as seen later. The literature reported the synthesis of nanofibers with AuNPs, where the nanoparticles were added to the fiber. These AuNPs were obtained through prior chemical synthesis, resulting in fibers of 400 nm, as reported by Nirwan et al. in 2019 [ 35 ]. Furthermore, in 2020, Manatunga et al. [ 36 ] reported a similar procedure but with the addition of nanoparticles post-electrospinning. They found that the distribution of AuNPs is homogeneous in all resulting nanofibers. However, unlike in this work, the distribution is only superficial, where the particles are found within the bulk and surface [ 30 ]. In Fig. 2 a), a STEM microscopy image of the Gel/PEO-AuNPs sample is shown, where it can be observed that the AuNPs predominantly exhibit hexagonal crystal shapes with sizes ranging from 6 nm to 44 nm, with an average of 12 nm. These measurements were obtained using ImageJ software with an average of 50 particles. It is noteworthy that the shape of nanoparticles, including AuNPs, can have a significant impact on their properties and potential applications. Thus, hexagonally shaped AuNPs are anisotropic nanostructures that have garnered considerable attention in recent decades for their applications in nanophotonics, surface-enhanced Raman scattering (SERS), biosensors, and optoelectronics. [ 37 ]. Furthermore, the shape of nanoparticles can influence their self-assembly ability and interaction with biological systems [ 38 ]. In this context, it has been observed that triangular AuNPs exhibit a higher capacity for analyte absorption compared to spherical AuNPs. Therefore, for specific applications, non-spherical nanoparticles are preferable [ 39 ], [ 40 ]. The synthesis method of AuNPs can influence the final shape of the nanoparticle, specifically in electrochemical synthesis. Some authors have shown that this shape directly impacts the properties and potential applications, as reported by Saldan and colleagues in 2017. They effectively obtained precisely dimensioned hexagonal AuNPs through the direct electron reduction of HAuCl 4 ▪3H 2 0 ions in the presence of poly(N-vinylpyrrolidone) (PVP). It was also demonstrated that the presence of the polymer improved the AuNPs formation process, significantly delaying the gold electrodeposition [ 40 ]. Additionally, Haro-Gonzalez and collaborators described in 2019 the synthesis of AuNPs through the electroreduction of HAuCl 4 ▪3H 2 0 as a precursor and PEG 20,000 as a stabilizing agent. The electrochemical method produced well-defined spherical particles, ranging in size from 1 to 20 nm, with an average size dispersion of 5 nm [ 41 ]. In Fig. 2 b), the diffraction pattern of the AuNPs is shown, where the diffraction rings from inside out can be indexed with the planes (111), (200), (220), and (311), respectively, which correspond to the FCC structure of gold (JCPDS 04-0784). Figure 3 shows the synthesized nanofibers with and without precursor and their respective UV-Vis spectra. There is an evident color change in the resulting matrices. In white (Fig. 3 b), the Gel/PEO AuNPs nanofibers without precursor are shown, along with their UV-Vis spectrum where no plasmon resonance is evident. Upon addition of the metallic precursor, a change to violet is observed in the nanofibers (Fig. 3 a). This color change suggests the formation of AuNPs, as reported by Saderi et al. in 2018, where nanofibers were synthesized, and later, the metallic precursor was added, causing a change in the color of the fibers due to the reduction of gold ions by the NH 2 groups of chitosan [ 42 ]. In this case, it originated from reducing the metallic precursor during electrospinning. After analyzing the UV-Vis spectrum, the appearance of a SPR at λmax 532 nm is shown, which is characteristic of AuNPs in a size range of 10 to 30 nm[ 43 ], [ 44 ] The results obtained by UV-Vis are similar to those reported by Duy et al., where they produced AuNPs in solution by gamma radiation, obtaining gold nanoparticles with a λ max of 537.5 nm and a size of ~ 36 nm. Similarly, there are reports of other methodologies for nanoparticle reduction using chemical methods, such as the one conducted by Himanshu Tyagi in 2016, where they used sodium citrate as a reducing agent and obtained similar results. However, the reported synthesis requires several purification steps and reducing agents and heat to induce nucleation [ 14 ]. Therefore, according to the literature, a change in color to purple and the SPR above 500 nm indicate AuNPs formation. Figure 4 presents the UV-Vis spectra illustrating the formation of fibers with the polymers obtained separately, as well as the influence of pH (acetic acid) and the metallic precursor. Samples for UV-Vis were prepared using 100 mg of the corresponding fiber. In the case of obtaining PEO fibers in pure water, there is no evidence of the presence of AuNPs' SPR, indicating no spontaneous formation of AuNPs. However, when obtaining the fibers with the addition of acetic acid, the AuNPs' plasmon resonance λ max at 547 nm, denoting the reduction of Au 3+ to Au 0 , is shown, apparently due to the change in pH from 6 to 4.6. In the medium, the deprotonation of acetic acid occurs, and its interaction with the functional groups of PEO increases the generation of electrons (e-) to reduce Au + 3 and form AuNPs, in addition to the influence of water hydrolysis originated by the high voltage used in the electrospinning process (14 kV). According to what was reported in 2016 by Himanshu Tyagi and collaborators, an acidic pH below six is necessary to obtain gold nanoparticles (AuNPs); a higher pH restricts nucleation and growth processes. [ 14 ] Upon analyzing the spectrum of gelatin fibers, with and without acetic acid, the plasmon band is observed at λ max 533 nm and λ max 535 nm, respectively, confirming the formation of AuNPs, unlike the spectrum with only PEO. In this case, the formation of AuNPs is closely related to pH and the composition and structure of gelatin, as the electron transfer between gelatin and gold ions strongly depends on these parameters. Thus, the interaction between the amino (NH 2 ) and carboxyl (COOH) groups of gelatin can interact with the surface of newly formed gold nanoparticles through electrostatic force [ 45 ]. Therefore, the amino groups can form coordination bonds with the gold atoms on the nanoparticle surface, contributing to stabilization. DosSantos et al. demonstrated that CMC acts as a reducing agent in the synthesis of AuNPs due to free amino groups forming hydrogen bridges with AuNPs, increasing their stability [ 38 ], [ 46 ], [ 47 ]. Therefore, based on these results, it can be evidenced that the reduction of gold ions in the Gelatin/PEO-AuNPs system, in this case, is governed by three processes as follows: I) the addition of acetic acid in low concentration, which influences the pH value; II) the presence of reducing groups such as the amino groups of Gelatin; and III) the applied voltage in the electrospinning process. Three control experiments were conducted to confirm those above, where AuNPs were obtained from three aqueous solutions with a 2% gold precursor. Chronoamperometry was performed for 5 minutes at a constant voltage of 1.3 V, exceeding the water hydrolysis potential see supplementary information section Therefore, the presence of acid in the process catalyzes the reaction, increasing the yield of AuNPs obtained through this synthesis. When comparing the SPR spectrum of AuNPs-PEO in an acidic medium, a considerable red shift towards λ max 542 nm is observed, indicating an increase in particle size or aggregation. However, when comparing the λ max of the individual systems (533 nm Gelac, 535 nm Gelw, and 542 nm PEOac) to the λ max of the complete Gel/PEO-AuNPs system (λ max 532 nm), it is observed that the value is closer to the λ max value of the Gel system in the presence of acid. This effect can be attributed to the fact that Gel has a more significant influence on the reduction and mainly the stabilization of the particle through its functional groups [ 48 ], in addition to the formation of fibers of only Gel and only PEO originating from solutions with different rheological properties. Therefore, when forming both the Taylor cone and the jet, and during the drying of the fiber towards the collector, it directly impacts the shape, size, and possible agglomeration. . Characterization by FTIR was carried out on electrospun fibers of Gel-PEO both with and without the presence of AuNPs and on pristine materials. Figure 5 shows the results for both systems. This characterization aims to evaluate the interaction of AuNPs with the polymers. The characteristic peak of 5a) PEO is found at 2873 cm –1 and is associated with the stretching of the aliphatic C-H group. Another minor band at 3300 cm − 1 is associated with the terminal OH- vibration, while the peak at 1466 cm − 1 corresponds to a scissoring bending of -CH 2 . Additionally, the peak at 1340 cm − 1 is associated with the wagging bending of -CH 2 , and the peak at 1085 cm − 1 is related to C-O-C stretching. Likewise, the peak at 960 cm − 1 is associated with the oscillation modes of -CH 2 -CH 2 and the vibration of C-O-C of PEO. Furthermore, in this spectrum, the amide I peak (C = O stretching) is evidenced at 1631 cm − 1 , the amide II peak (NH bending) at 1525 cm − 1 , the amide III peak (CN stretching plus NH in phase bending) at 1234 cm − 1 , and the amide A peak (NH stretching vibration) at 3288 cm − 1 , which are distinctive characteristics of gelatin 5b).[ 39 ], [ 46 ]. In the sample spectrum, characteristic bands of both polymers are observed. The interaction between PEO and gelatin is evidenced by the formation of a band of greater amplitude in the region of 3300 cm − 1 , caused by the summation of the vibration of the -OH bands and the peak of amide A of both PEO and gelatin, suggesting the possible formation of hydrogen bonds between the two polymers. Additionally, other studies, such as the one reported by Rahma et al. in 2010, [ 49 ] supports the miscibility between gelatin and PEO, showing the formation of hydrogen bonds between the ether groups of PEO and the amino groups of gelatin. In Fig. 5 c) (PEO/Gel blank), subtle shifts in the positions of the amide-I and amide-II bands are observed, from 1631 to 1650 cm − 1 and from 1525 to 1542 cm − 1 , respectively, compared to the pristine polymer. Furthermore, the hydrogen bonding of the amino group in gelatin and the hydrogen in PEO can act as electron donors and acceptors, resulting in a dipole-dipole interaction. [ 50 ]. Similarly, in Fig. 5 d), the interaction of gelatin-PEO nanofibers with AuNPs is shown, where no changes in the intensity of the bands, shifts, or the formation of new bands are evident; this could be attributed to the fact that the interaction of AuNPs is closely linked to the amount of the gold precursor HAuCl 4 ▪3H 2 0 deposited; therefore, if the deposited amount is meager, it may not be sufficient to induce significant changes. Similarly, in 2017, Ahmed Al-Kattan et al.[ 35 ], they reported the synthesis of nanofibers composed of chitosan and PEO with the addition of AuNPs, without any evidence of any effect on shape, intensity, or formation of additional bands to those of chitosan and PEO nanofibers after the incorporation of AuNPs. These results are similar to those reported in this work. Additionally, according to the reports of Manatunga et al., who in 2020 carried out the synthesis of gelatin and PEO fibers with the subsequent incorporation of gold nanoparticles (AuNPs), they maintain that no significant changes are observed in their material due to the overlap of signals between these materials [ 36 ]. . 4. Conclusions An innovative, simple, and cost-effective method has been developed for synthesizing gold nanoparticles through the spontaneous reduction of HAuCl 4 ▪3H 2 0 by the electrospinning technique. This approach eliminates the need for additional synthesis steps once the precursor is loaded into the fibers and the application of heat or additional reducing agents. The reduction of gold ions in this method is influenced by three fundamental processes: I) the addition of acetic acid, which adjusts the pH value; II) the presence of reducing groups, such as the amino groups of gelatin; and III) the applied voltage during the electrospinning process. A distinctive feature of this approach is its ability to perform the entire process in a single step, meaning that the polymeric matrix is formed simultaneously with the gold nanoparticles, allowing their assembly and stabilization during the process. This method could pave the way for developing a new methodology to synthesize metal nanoparticles under specific conditions. Declarations Author Contribution. GE, CC- Conceptualization, CC, AA, DIG, JZ, RL Methodology and Formal Analysis, GE,CC, JZ, GG- Writing (Original Draft). Funding. This research work was funded by CONAHCyT Fund Projects under grant no. (A1S8638). Data availability . The data that support the findings of this study are available from the corresponding author, Gethzemani Estrada-Villegas, upon reasonable request. Ethics approval and consent to participate The facts and views in the manuscript are solely ours, and we are totally responsible for authenticity, validity, and originality. We also declare that this manuscript is our original work, and we have not copied from anywhere else. There is no plagiarism in my manuscript. Consent for publication. We undertake and agree that the manuscript submitted to your journal has not been published elsewhere and has not been simultaneously submitted to other journals. Competing interests. The authors declare no conflict of interest References H. Reza Ghorbani, M. Molaei -, A. Mary Ealias, and S. M. P, “A review on the classification, characterisation, synthesis of nanoparticles and their application Related content Synthesis of Aluminium Nanoparticles in A Water/Polyethylene Glycol Mixed Solvent using-EDM R.K. Sahu and Somashekhar S Hiremath-Particle pr”, doi: 10.1088/1757-899X/263/3/032019. S. Kumar, P. Bhushan, and S. Bhattacharya, “Fabrication of Nanostructures with Bottom-up Approach and Their Utility in Diagnostics, Therapeutics, and Others,” Environmental, Chemical and Medical Sensors , p. 167, 2018, doi: 10.1007/978-981-10-7751-7_8. I. H. El-Sayed, X. Huang, and M. A. El-Sayed, “Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles,” Cancer Lett , vol. 239, no. 1, pp. 129–135, Jul. 2006, doi: 10.1016/J.CANLET.2005.07.035. M. Huang et al. , “Bragg reflectors; (140.3600) Lasers, tunable; (140.3070) Infrared and far-infrared lasers,” Nat. Photonics , vol. 17, no. 18, p. 10, 2009. K. Esumi, N. Takei, and T. Yoshimura, “Antioxidant-potentiality of gold-chitosan nanocomposites,” Colloids Surf B Biointerfaces , vol. 32, no. 2, pp. 117–123, Oct. 2003, doi: 10.1016/S0927-7765(03)00151-6. N. O. Yakimovich, A. A. Ezhevskii, D. V. Guseinov, L. A. Smirnova, T. A. Gracheva, and K. S. Klychkov, “Antioxidant properties of gold nanoparticles studied by ESR spectroscopy,” Russian Chemical Bulletin 2008 57:3 , vol. 57, no. 3, pp. 520–523, Mar. 2009, doi: 10.1007/S11172-008-0080-1. K. J, D. Z, and K. BD, “Cryogenic CO2 formation on oxidized gold clusters synthesized via reactive layer assisted deposition,” J Am Chem Soc , vol. 127, no. 42, pp. 14592–14593, Nov. 2005, doi: 10.1021/JA055764Z. C. WS et al. , “Size-dependent tissue kinetics of PEG-coated gold nanoparticles,” Toxicol Appl Pharmacol , vol. 245, no. 1, pp. 116–123, May 2010, doi: 10.1016/J.TAAP.2010.02.013. S. Marx, M. V. Jose, J. D. Andersen, and A. J. Russell, “Electrospun gold nanofiber electrodes for biosensors,” Biosens Bioelectron , vol. 26, no. 6, pp. 2981–2986, Feb. 2011, doi: 10.1016/J.BIOS.2010.11.050. P. Z. Chen and F. X. Gu, “Gold nanoparticles for colorimetric detection of pathogens,” Encyclopedia of Biomedical Engineering , vol. 1–3, pp. 108–115, Jan. 2019, doi: 10.1016/B978-0-12-801238-3.99873-8. E. Sapountzi, M. Braiek, F. Vocanson, J.-F. O. Chateaux, N. Jaffrezic-Renault, and F. Lagarde, “Gold nanoparticles assembly on electrospun poly(vinyl alcohol)/poly(ethyleneimine)/glucose oxidase nanofibers for ultrasensitive electrochemical glucose biosensing,” Sens Actuators B Chem , vol. 238, pp. 392–401, 2017, doi: 10.1016/j.snb.2016.07.062. A. D. Dwivedi and K. Gopal, “Biosynthesis of silver and gold nanoparticles using Chenopodium album leaf extract,” Colloids Surf A Physicochem Eng Asp , vol. 369, no. 1–3, pp. 27–33, Oct. 2010, doi: 10.1016/J.COLSURFA.2010.07.020. J. J. Zhang, M. M. Gu, T. T. Zheng, and J. J. Zhu, “Synthesis of gelatin-stabilized gold nanoparticles and assembly of carboxylic single-walled carbon nanotubes/Au composites for cytosensing and drug uptake,” Anal Chem , vol. 81, no. 16, pp. 6641–6648, Aug. 2009, doi: 10.1021/ac900628y. H. Tyagi, A. Kushwaha, A. Kumar, and M. Aslam, “A Facile pH Controlled Citrate-Based Reduction Method for Gold Nanoparticle Synthesis at Room Temperature,” Nanoscale Res Lett , vol. 11, no. 1, Dec. 2016, doi: 10.1186/s11671-016-1576-5. B. Contreras-Trigo et al. , “Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method,” Sensors (Basel) , vol. 18, no. 7, Jul. 2018, doi: 10.3390/S18072246. S. S. R. Dasary, A. K. Singh, D. Senapati, H. Yu, and P. C. Ray, “Gold nanoparticle based label-free SERS probe for ultrasensitive and selective detection of trinitrotoluene,” J Am Chem Soc , vol. 131, no. 38, pp. 13806–13812, 2009, doi: 10.1021/JA905134D. N. N. Duy, D. T. T. Thao, H. T. D. Quy, D. Van Phu, B. D. Du, and nguyen Q. Hien, “Synthesis of gelatin stabilized gold nanoparticles with seed particles enlargement by gamma Co-60 irradiation,” Vietnam Journal of Chemistry , vol. 55, no. 2, p. 211, Apr. 2017, doi: 10.15625/2525-2321.2017-00446. C.-C. Wu, D.-H. Chen, and W. G. Org, “Facile green synthesis of gold nanoparticles with gum arabic as a stabilizing agent and reducing agent,” Gold Bull , vol. 43, 2010, Accessed: Feb. 26, 2023. [Online]. Available: www.goldbulletin.org N. N. Duy, D. X. Du, D. Van Phu, L. A. Quoc, B. D. Du, and N. Q. Hien, “Synthesis of gold nanoparticles with seed enlargement size by γ-irradiation and investigation of antioxidant activity,” Colloids Surf A Physicochem Eng Asp , vol. 436, pp. 633–638, Sep. 2013, doi: 10.1016/J.COLSURFA.2013.07.038. N. Q. Hien, D. Van Phu, N. N. Duy, and L. A. Quoc, “Radiation synthesis and characterization of hyaluronan capped gold nanoparticles,” Carbohydr Polym , vol. 89, no. 2, pp. 537–541, Jun. 2012, doi: 10.1016/J.CARBPOL.2012.03.041. Y. Huang, Y. Fang, L. Chen, A. Lu, and L. Zhang, “One-step synthesis of size-tunable gold nanoparticles immobilized on chitin nanofibrils via green pathway and their potential applications,” Chemical Engineering Journal , vol. 315, pp. 573–582, 2017, doi: 10.1016/j.cej.2017.01.065. J. Bai et al. , “A simple and effective route for the preparation of poly(vinylalcohol) (PVA) nanofibers containing gold nanoparticles by electrospinning method,” Solid State Commun , vol. 141, pp. 292–295, 2007, doi: 10.1016/j.ssc.2006.10.024. S. Shankar, L. Jaiswal, P. R. Selvakannan, K. S. Ham, and J. W. Rhim, “Gelatin-based dissolvable antibacterial films reinforced with metallic nanoparticles,” RSC Adv , vol. 6, no. 71, pp. 67340–67352, Jul. 2016, doi: 10.1039/C6RA10620J. L. M. Duque Sánchez, L. Rodriguez, and M. López, “Enero de 2013 Duque et al. Electrospinning 10,” 2014. Accessed: Apr. 06, 2019. [Online]. Available: http://www.ehu.eus/reviberpol/pdf/ENE13/duque.pdf F. Topuz, M. A. Abdulhamid, T. Holtzl, and G. Szekely, “Nanofiber engineering of microporous polyimides through electrospinning: Influence of electrospinning parameters and salt addition,” Mater Des , vol. 198, p. 109280, 2021, doi: 10.1016/j.matdes.2020.109280. N. Bhardwaj and S. C. Kundu, “Electrospinning: A fascinating fiber fabrication technique,” Biotechnol Adv , vol. 28, no. 3, pp. 325–347, 2010, doi: 10.1016/j.biotechadv.2010.01.004. “Sci-Hub | Electrospinning of Nanofibers: Reinventing the Wheel? Advanced Materials, 16(14), 1151–1170 | 10.1002/adma.200400719.” Accessed: Aug. 21, 2023. [Online]. Available: https://sci-hub.se/https://doi.org/10.1002/adma.200400719 “A Novel Approach to Prepare Gold Nanoparticles_Polyacrylamide Composite Nanofibers.pdf - Google Drive.” Y. Zhang et al. , “New gold nanostructures for sensor applications: A review,” Materials , vol. 7, no. 7, pp. 5169–5201, 2014, doi: 10.3390/ma7075169. P. Balashanmugam, G. Sucharithra, A. M. S., and T. S. A., “Efficacy of biopolymeric PVA-AuNPs and PCL-Curcumin loaded electrospun nanofibers and their anticancer activity against A431 skin cancer cell line,” Mater Today Commun , vol. 25, no. May, p. 101276, 2020, doi: 10.1016/j.mtcomm.2020.101276. D. V. Havaldar, R. V. Patil, D. N. Moholkar, P. S. Magdum, A. P. Vadrale, and K. D. Pawar, “Differently synthesized gold nanoparticles respond differently to functionalization with L-amino acids,” Particuology , vol. 52, pp. 97–104, Oct. 2020, doi: 10.1016/J.PARTIC.2019.12.010. T. M. Righi, R. S. Almeida, and M. A. d’Ávila, “Electrospinning of Gelatin/PEO Blends: Influence of Process Parameters in the Nanofiber Properties,” Macromol Symp , vol. 319, no. 1, pp. 230–234, Sep. 2012, doi: 10.1002/MASY.201100137. N. Amiri, Z. Rozbeh, T. Afrough, S. A. Sajadi Tabassi, A. Moradi, and J. Movaffagh, “Optimization of Chitosan-Gelatin Nanofibers Production: Investigating the Effect of Solution Properties and Working Parameters on Fibers Diameter,” Bionanoscience , vol. 8, no. 3, pp. 778–789, Sep. 2018, doi: 10.1007/s12668-018-0540-5. N. A. M. Barakat, M. A. Kanjwal, F. A. Sheikh, and H. Y. Kim, “Spider-net within the N6, PVA and PU electrospun nanofiber mats using salt addition: Novel strategy in the electrospinning process,” Polymer (Guildf) , vol. 50, no. 18, pp. 4389–4396, Aug. 2009, doi: 10.1016/J.POLYMER.2009.07.005. V. P. Nirwan, A. Al-Kattan, A. Fahmi, and A. V Kabashin, “Fabrication of Stable Nanofiber Matrices for Tissue Engineering via Electrospinning of Bare Laser-Synthesized Au Nanoparticles in Solutions of High Molecular Weight Chitosan”, doi: 10.3390/nano9081058. K. M. Nalin De Silva et al. , “royalsocietypublishing.org/journal/rsos Research Nanofibrous cosmetic face mask for transdermal delivery of nano gold: synthesis, characterization, release and zebra fish employed toxicity studies,” 2023, doi: 10.1098/rsos.201266. L. Ge and J. Tang, “Synthesis of Hexagonal Gold Nanoparticles and Study of its Optical and Near-field Distribution Properties by Discrete Dipole Approximation,” in Journal of Physics: Conference Series , IOP Publishing Ltd, Feb. 2022. doi: 10.1088/1742-6596/2185/1/012077. M. A. R. Khan et al. , “A review on gold nanoparticles: Biological synthesis, characterizations, and analytical applications,” Results in Chemistry , vol. 4. Elsevier B.V., Jan. 01, 2022. doi: 10.1016/j.rechem.2022.100478. K. I. Requejo, A. V. Liopo, and E. R. Zubarev, “High yield synthesis and surface chemistry exchange of small gold hexagonal nanoprisms,” Chemical Communications , vol. 55, no. 76, pp. 11422–11425, 2019, doi: 10.1039/C9CC04534A. I. Saldan et al. , “Electrochemical synthesis and properties of gold nanomaterials,” Journal of Solid State Electrochemistry , vol. 22, no. 3. Springer New York LLC, pp. 637–656, Mar. 01, 2018. doi: 10.1007/s10008-017-3835-5. P. G. Haro-González, S. Ramírez-Rico, and E. R. Larios-Durán, “ELECTROCHEMICAL SCIENCE Synthesis of Gold Nanoparticles in Aqueous Solutions by Electrochemical Reduction Using poly(ethylen glicol) as Stabilizer,” Int. J. Electrochem. Sci , vol. 14, pp. 9704–9710, 2019, doi: 10.20964/2019.10.10. N. Saderi, M. Rajabi, B. Akbari, M. Firouzi, and Z. Hassannejad, “Fabrication and characterization of gold nanoparticle-doped electrospun PCL/chitosan nanofibrous scaffolds for nerve tissue engineering,” J Mater Sci Mater Med , vol. 29, no. 9, pp. 1–10, Sep. 2018, doi: 10.1007/S10856-018-6144-3/FIGURES/5. A. M. Abdelghany, E. M. Abdelrazek, S. I. Badr, M. S. Abdel-Aziz, and M. A. Morsi, “Effect of Gamma-irradiation on biosynthesized gold nanoparticles using Chenopodium murale leaf extract,” Journal of Saudi Chemical Society , vol. 21, no. 5, pp. 528–537, Jul. 2017, doi: 10.1016/j.jscs.2015.10.002. M. P. Neupane et al. , “Synthesis of gelatin-capped gold nanoparticles with variable gelatin concentration,” Journal of Nanoparticle Research , vol. 13, no. 2, pp. 491–498, Feb. 2011, doi: 10.1007/s11051-010-9971-9. M. Borzenkov, G. Chirico, M. Collini, and P. Pallavicini, “Gold Nanoparticles for Tissue Engineering,” 2018, pp. 343–390. doi: 10.1007/978-3-319-76090-2_10. D. S. Dos Santos, P. J. G. Goulet, N. P. W. Pieczonka, O. N. Oliveira, and R. F. Aroca, “Gold nanoparticle embedded, self-sustained chitosan films as substrates for surface-enhanced Raman scattering,” Langmuir , vol. 20, no. 23, pp. 10273–10277, Nov. 2004, doi: 10.1021/la048328j. R. M. Tripathi, S. Y. Yoon, D. Ahn, and S. J. Chung, “Facile Synthesis of Triangular and Hexagonal Anionic Gold Nanoparticles and Evaluation of Their Cytotoxicity,” Nanomaterials , vol. 9, no. 12, Dec. 2019, doi: 10.3390/NANO9121774. S. Suarasan, M. Focsan, O. Soritau, D. Maniu, and S. Astilean, “One-pot, green synthesis of gold nanoparticles by gelatin and investigation of their biological effects on Osteoblast cells,” Colloids Surf B Biointerfaces , vol. 132, pp. 122–131, Aug. 2015, doi: 10.1016/j.colsurfb.2015.05.009. M. A. Rahman, M. A. Khan, and S. M. Tareq, “Preparation and Characterization of Polyethylene Oxide (PEO)/Gelatin Blend for Biomedical Application: Effect of Gamma Radiation,” J Appl Polym Sci , vol. 117, pp. 2075–2082, 2010, doi: 10.1002/app.32034. I. Yakimets, S. S. Paes, N. Wellner, A. C. Smith, R. H. Wilson, and J. R. Mitchell, “Effect of water content on the structural reorganization and elastic properties of biopolymer films: A comparative study,” Biomacromolecules , vol. 8, no. 5, pp. 1710–1722, May 2007, doi: 10.1021/BM070050X/ASSET/IMAGES/MEDIUM/BM070050XN00001.GIF. supplementary information supplementary information is not available with this version Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Introduction","content":"\u003cp\u003eThe synthesis methods for producing metallic nanoparticles include chemical reactions, physical methods, or biological methods, which can be divided into \"Bottom Up\" approaches, where nanoparticles are obtained from molecular or atomic level precursors, and \"Top Down\" methods, where nanoparticles are obtained by reducing the size of a metallic precursor.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. One of the most commonly used Bottom-Up methods involves the reduction of metallic precursors such as salts or acids. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThus, it has been proven that gold nanoparticles (AuNPs) with different sizes and shapes exhibit optical [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e], [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], antioxidant [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], catalytic [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], and unique chemical properties [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Due to these properties, they have been used in different technological applications, such as biosensor production, catalysis, and drug delivery, among others [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe synthesis of AuNPs with desired size and shape is of great importance in scientific research and practical applications, as small variations in size or shape can significantly impact various physical properties of nanostructures. Therefore, several methodologies have been used to adjust their size, such as: a) variations in precursor concentration [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]; b) molecular weight and type of stabilizing agent [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]; c) pH [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] and d) reducing agent [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThere are several methods for synthesizing gold nanoparticles. One of the most common methods is the chemical reduction method, where gold ions (Au\u003csup\u003e3+\u003c/sup\u003e) are reduced to gold atoms (Au\u003csup\u003e0\u003c/sup\u003e) in solution using a reducing agent. Typical reducing agents include sodium borohydride (NaBH\u003csub\u003e4\u003c/sub\u003e), hydrazine, and sodium citrate [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Sodium citrate is mainly used to obtain colloidal gold nanoparticles stabilized by citrate. Gold nanoparticles can also be synthesized using radiation, such as ultraviolet (UV) light or gamma radiation [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].Green methods commonly use extracts from plants or other natural sources rich in reducing compounds as reducing agents for the synthesis [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. This method is considered more environmentally friendly and can lead to the formation of nanoparticles with unique properties.\u003c/p\u003e \u003cp\u003eOn the other hand, metallic nanoparticles tend to agglomerate or precipitate due to Van der Waals forces and high surface energy. Stabilizing agents, such as polymers, prevent this from happening and maintain a stable dispersion of these nanoparticles in solution [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In this sense, polymers provide a protective barrier that prevents agglomeration and sedimentation, maintaining a stable dispersion in solution. [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eAn example is the study conducted by Bai et al. in 2007, where polyvinyl alcohol (PVA) nanofibers decorated with gold nanoparticles were produced without the need for stabilizing agents, owing to the presence of polyvinyl alcohol, which acts as such. Another example is demonstrated by Huang et al. in 2017, where they concluded that previously synthesized chitosan nanofibers act both as a reducing agent for AuNPs synthesis and as a stabilizer for the generated AuNPs, due to the reduction and chelation capacity of the amino groups in chitin [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Thus, it has been demonstrated that the stabilizing influence of polymers originates from their chemical nature, specifically from the functional groups [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. For example, polyethylene oxide and bovine skin gelatin are good stabilizing agents in nanoparticle synthesis due to the presence of their functional groups, such as -NH\u003csub\u003e2\u003c/sub\u003e, -SH, and -COOH [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePolymer nanofibers obtained by electrospinning typically have diameters in the nanometer range (typically between 100 nm and 1 \u0026micro;m) [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Nanofibers can be generated from different polymers, thus exhibiting diverse physical properties and potential applications. Nanofibers often possess a high surface-to-volume ratio, making them suitable for applications where surface area is crucial, such as filtration, controlled drug release, and tissue engineering [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThere are many different methods for producing nanofibers, including force spinning, meltdown, and electrospinning [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Electrospinning is one of the most widely used methods for generating nanofibers due to its simple setup, the ability to mass-produce continuous nanofibers from various synthetic and natural polymers, the capability to incorporate various types of biological molecules into them, as well as producing ultrafine fibers with controllable diameters, compositions, and orientations [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eCombining nanofibers and metallic nanoparticles has led to hybrid structures with unique and diverse properties. Precious metals, such as gold, silver, platinum, etc., have been used to develop these materials [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Hybrids composed of polymer fibers and AuNPs have applications in catalysis, electronics, drug release devices, and sensors. AuNPs can be attached to functional nanofibers to create highly sensitive sensors for detecting specific molecules, such as biomarkers or contaminants in water and air [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. For example, in 2017 E. Sapountzki et al. developed a glucose sensor based on nanofibers obtained through the electrospinning method. After synthesizing the fibers, they were decorated with enzymes anchored to AuNPs [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eOn the other hand, in 2020, Balashanmugam et al. synthesized AuNPs using a chemical method. They added them to a solution of PVA and PCL, which was then electrospun to obtain nanofibers for drug delivery purposes. The antioxidant and anticancer activities were studied in vitro. The results showed that the treatment with nanoparticles and nanofibers exhibited cytotoxicity on cancer cells through apoptosis but lower toxicity on normal cells compared to commercial drugs [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs shown in the previous examples, it has been reported that AuNPs can be synthesized and incorporated before or after the electrospinning process. Before electrospinning, the particles are synthesized using traditional chemical methods, and once obtained, they are incorporated into the solution that will be used during the process. The metallic precursor is added to the polymeric solution for synthesis after electrospinning. Once the nanofibers are synthesized, the nucleation of the AuNPs can occur using various methods such as gamma radiation, UV, or adding a reducing agent at a specific temperature [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, this work aims to develop a new synthesis route for the simultaneous production of AuNPs and nanofibers without reducing agents, and this would allow clean nanoparticles to be obtained for subsequent applications in many areas. Currently, there are no reports of the proposed methodology, and compared to the methods described previously, the synthesis of AuNPs by the electrospinning technique is considered a method that presents several advantages: The reaction is carried out at room temperature, the yield of the NPs is high because it does not require any purification process, the synthesis of the NPs does not require any external reducing agent, the synthesis of the NPs and the fibers is carried out simultaneously without any previous or additional steps.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials and Methods\u003c/h2\u003e \u003cp\u003ePoly(ethylene oxide) (PEO, Mw 600,000 g/mol), gelatin from porcin skin (gel strength 300, type A) were used for the synthesis of the fibers, gold (III) chloride hydrate (HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0, 99.99% trace metals basis), acetic acid glacial, Reagent Plus 99%, were purchased from Sigma-Aldrich and used as received without further purification. Polymer solutions were prepared with Milli-Q water.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preparation of electrospinning solution\u003c/h2\u003e \u003cp\u003eA 7% (w/v) aqueous solution of PEO and gelatin using Milli-Q water was prepared by dissolving the polymers at 55\u0026deg;C and 40\u0026deg;C, respectively, and stirring for 5 hours. Then, the solutions were mixed at a 1:1 ratio of gelatin to PEO, and the gold precursor was added at a concentration of 0.10 mmol L\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e dissolved in 400 \u0026micro;L of water-acetic acid solution with a ratio of 60:40. Similarly, Gelatin/PEO fibers were obtained without the Au precursor.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Fabrication of Gel/PEO- AuNPs electrospun nanofibrous membrane\u003c/h2\u003e \u003cp\u003eThe electrospinning process was conducted using an Innovenso NS24 Electrospinning Machine. The solution was loaded into a 10 mL syringe equipped with a metal spinneret (21 G) and attached to a syringe pump (Innovenso IPS-12). The solution was ejected from the syringe at a rate of 0.4 mL h\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e using a high voltage power supply set at 14 kV, positioned between the needle and a grounded collector covered with aluminum foil. The distance between the needle and the collector was 13 cm. Electrospinning took place at a temperature of 24\u0026deg;C.\u003c/p\u003e \u003cp\u003eThe formation of Gel/PEO- AuNPs by electrospinning is represented in scheme \u003cspan refid=\"Sch1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Characterization of the AuNP/Gelatin-PEO electrospun nanofibrous membrane\u003c/h2\u003e \u003cp\u003eThe FT-IR transmittance spectra were conducted using a single-beam Fourier transform infrared spectrometer (Nicolet iS10, USA). Spectra were measured in the spectral range of 4000\u0026ndash;400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to analyze the chemical composition of the samples.\u003c/p\u003e \u003cp\u003eFiber diameters were determined using scanning electron microscopy (SEM), with images obtained using an SEM Jeol JSM-IT800. The average diameter and standard deviation were calculated from a sample of at least 100 fibers using Image J software.\u003c/p\u003e \u003cp\u003eTransmission electron microscopy (TEM) images were acquired using an FEI, TITAN G2 80\u0026ndash;300 instrument, equipped with High-Angle Annular Dark Field (HAADF), Bright Field (BF) and Annular Dark Field (ADF) detectors for Scanning Transmission Electron Microscopy (STEM) mode. During electrospinning, fibers containing AuNPs were collected on a TEM Cu-grid for subsequent analysis.\u003c/p\u003e \u003cp\u003eThe surface plasmon resonance (SPR) of gold nanoparticles at λ\u003csub\u003emax\u003c/sub\u003e 550 was characterized by scanning from 400 to 700 nm using a UV-Vis Spectrophotometer (Shimadzu Uv-1900i) with a 1 cm quartz cell. Approximately, 10 milligrams of the sample were weighed and placed in 3 mL of a water-acetic acid solution (60:40 ratio). The solution was then vortexed for 5 minutes before taking the readings (60:40 ratio). The solution was then vortexed for 5 minutes before taking the readings.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussions","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Preparation of Gelatin/PEO fibers with and without precursor\u003c/h2\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea), SEM microscopy images of Gelatin/PEO composite fibers obtained by electrospinning from a pure water-based solution. The resulting fibers exhibited a smooth, cylindrical morphology without alignment and no bead-like defects along the resulting matrix. The average diameter of the fibers was 183 nm\u0026thinsp;\u0026plusmn;\u0026thinsp;22 compared to those developed by Thiago M. Righi et al. [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], who reported in 2012 the production of gelatin and PEO nanofibers in acetic acid-water, where they obtained diameters ranging from 160 nm to 1.2 microns. They added NaCl to improve the conductivity of the solution, obtaining smaller diameters and improving morphology; however, the dispersion was very high. In 2019, Nafise Amiri et al. developed fibers using the proposed polymers. They reported the impact on fiber diameter caused by the properties of the solution and working parameters, where they obtained diameters of 229.79\u0026thinsp;\u0026plusmn;\u0026thinsp;41.45 to 308.66\u0026thinsp;\u0026plusmn;\u0026thinsp;50.03 nm, closer to those reported in this work. However, they used acetic acid as a solvent, improving the conductivity of the solution and resulting in a defect-free diameter and morphology. [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eOn the other hand, the impact on the morphology of the nanofibers from solutions prepared with the metallic precursor HAuCl\u003csub\u003e4\u003c/sub\u003e\u0026middot;3H\u003csub\u003e2\u003c/sub\u003eO in water using 2% acetic acid was studied. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb shows the Gelatin/PEO-HAuCl\u003csub\u003e4\u003c/sub\u003e\u0026middot;3H\u003csub\u003e2\u003c/sub\u003eO fibers, where a reduction in fiber size was observed, resulting in an average diameter of 145\u0026thinsp;\u0026plusmn;\u0026thinsp;17 nm. This phenomenon could be attributed to the increased conductivity of the Gel/PEO system due to the interaction between the precursor ions, which generates charged groups in the structure of the system [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e], leading to stronger elongation forces in the polymer jet and thus resulting in a decrease in fiber diameter. Additionally, the formation of bright structures after the electrospinning process can be observed, which may indicate the formation of Au nanoparticles during the process; due to the presence of polymer as a stabilizing agent, the formation of AuNPs is presumed, however, more detail studies are in order to confirm such assertion. These were characterized by UV-Vis spectroscopy and TEM to determine their nature, as seen later. The literature reported the synthesis of nanofibers with AuNPs, where the nanoparticles were added to the fiber. These AuNPs were obtained through prior chemical synthesis, resulting in fibers of 400 nm, as reported by Nirwan et al. in 2019 [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurthermore, in 2020, Manatunga et al. [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] reported a similar procedure but with the addition of nanoparticles post-electrospinning. They found that the distribution of AuNPs is homogeneous in all resulting nanofibers. However, unlike in this work, the distribution is only superficial, where the particles are found within the bulk and surface [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea), a STEM microscopy image of the Gel/PEO-AuNPs sample is shown, where it can be observed that the AuNPs predominantly exhibit hexagonal crystal shapes with sizes ranging from 6 nm to 44 nm, with an average of 12 nm. These measurements were obtained using ImageJ software with an average of 50 particles. It is noteworthy that the shape of nanoparticles, including AuNPs, can have a significant impact on their properties and potential applications. Thus, hexagonally shaped AuNPs are anisotropic nanostructures that have garnered considerable attention in recent decades for their applications in nanophotonics, surface-enhanced Raman scattering (SERS), biosensors, and optoelectronics. [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurthermore, the shape of nanoparticles can influence their self-assembly ability and interaction with biological systems [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. In this context, it has been observed that triangular AuNPs exhibit a higher capacity for analyte absorption compared to spherical AuNPs. Therefore, for specific applications, non-spherical nanoparticles are preferable [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe synthesis method of AuNPs can influence the final shape of the nanoparticle, specifically in electrochemical synthesis. Some authors have shown that this shape directly impacts the properties and potential applications, as reported by Saldan and colleagues in 2017. They effectively obtained precisely dimensioned hexagonal AuNPs through the direct electron reduction of HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0 ions in the presence of poly(N-vinylpyrrolidone) (PVP). It was also demonstrated that the presence of the polymer improved the AuNPs formation process, significantly delaying the gold electrodeposition [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]. Additionally, Haro-Gonzalez and collaborators described in 2019 the synthesis of AuNPs through the electroreduction of HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0 as a precursor and PEG 20,000 as a stabilizing agent. The electrochemical method produced well-defined spherical particles, ranging in size from 1 to 20 nm, with an average size dispersion of 5 nm [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb), the diffraction pattern of the AuNPs is shown, where the diffraction rings from inside out can be indexed with the planes (111), (200), (220), and (311), respectively, which correspond to the FCC structure of gold (JCPDS 04-0784).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows the synthesized nanofibers with and without precursor and their respective UV-Vis spectra. There is an evident color change in the resulting matrices. In white (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb), the Gel/PEO AuNPs nanofibers without precursor are shown, along with their UV-Vis spectrum where no plasmon resonance is evident. Upon addition of the metallic precursor, a change to violet is observed in the nanofibers (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). This color change suggests the formation of AuNPs, as reported by Saderi et al. in 2018, where nanofibers were synthesized, and later, the metallic precursor was added, causing a change in the color of the fibers due to the reduction of gold ions by the NH\u003csub\u003e2\u003c/sub\u003e groups of chitosan [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]. In this case, it originated from reducing the metallic precursor during electrospinning. After analyzing the UV-Vis spectrum, the appearance of a SPR at λmax 532 nm is shown, which is characteristic of AuNPs in a size range of 10 to 30 nm[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e], [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe results obtained by UV-Vis are similar to those reported by Duy et al., where they produced AuNPs in solution by gamma radiation, obtaining gold nanoparticles with a λ\u003csub\u003emax\u003c/sub\u003e of 537.5 nm and a size of ~\u0026thinsp;36 nm. Similarly, there are reports of other methodologies for nanoparticle reduction using chemical methods, such as the one conducted by Himanshu Tyagi in 2016, where they used sodium citrate as a reducing agent and obtained similar results. However, the reported synthesis requires several purification steps and reducing agents and heat to induce nucleation [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Therefore, according to the literature, a change in color to purple and the SPR above 500 nm indicate AuNPs formation.\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e presents the UV-Vis spectra illustrating the formation of fibers with the polymers obtained separately, as well as the influence of pH (acetic acid) and the metallic precursor. Samples for UV-Vis were prepared using 100 mg of the corresponding fiber. In the case of obtaining PEO fibers in pure water, there is no evidence of the presence of AuNPs' SPR, indicating no spontaneous formation of AuNPs. However, when obtaining the fibers with the addition of acetic acid, the AuNPs' plasmon resonance λ\u003csub\u003emax\u003c/sub\u003e at 547 nm, denoting the reduction of Au\u003csup\u003e3+\u003c/sup\u003e to Au\u003csup\u003e0\u003c/sup\u003e, is shown, apparently due to the change in pH from 6 to 4.6. In the medium, the deprotonation of acetic acid occurs, and its interaction with the functional groups of PEO increases the generation of electrons (e-) to reduce Au\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e and form AuNPs, in addition to the influence of water hydrolysis originated by the high voltage used in the electrospinning process (14 kV). According to what was reported in 2016 by Himanshu Tyagi and collaborators, an acidic pH below six is necessary to obtain gold nanoparticles (AuNPs); a higher pH restricts nucleation and growth processes. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eUpon analyzing the spectrum of gelatin fibers, with and without acetic acid, the plasmon band is observed at λ\u003csub\u003emax\u003c/sub\u003e 533 nm and λ\u003csub\u003emax\u003c/sub\u003e 535 nm, respectively, confirming the formation of AuNPs, unlike the spectrum with only PEO. In this case, the formation of AuNPs is closely related to pH and the composition and structure of gelatin, as the electron transfer between gelatin and gold ions strongly depends on these parameters. Thus, the interaction between the amino (NH\u003csub\u003e2\u003c/sub\u003e) and carboxyl (COOH) groups of gelatin can interact with the surface of newly formed gold nanoparticles through electrostatic force [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Therefore, the amino groups can form coordination bonds with the gold atoms on the nanoparticle surface, contributing to stabilization. DosSantos et al. demonstrated that CMC acts as a reducing agent in the synthesis of AuNPs due to free amino groups forming hydrogen bridges with AuNPs, increasing their stability [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e], [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e], [\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]. Therefore, based on these results, it can be evidenced that the reduction of gold ions in the Gelatin/PEO-AuNPs system, in this case, is governed by three processes as follows: I) the addition of acetic acid in low concentration, which influences the pH value; II) the presence of reducing groups such as the amino groups of Gelatin; and III) the applied voltage in the electrospinning process. Three control experiments were conducted to confirm those above, where AuNPs were obtained from three aqueous solutions with a 2% gold precursor. Chronoamperometry was performed for 5 minutes at a constant voltage of 1.3 V, exceeding the water hydrolysis potential see supplementary information section\u003c/p\u003e \u003cp\u003eTherefore, the presence of acid in the process catalyzes the reaction, increasing the yield of AuNPs obtained through this synthesis. When comparing the SPR spectrum of AuNPs-PEO in an acidic medium, a considerable red shift towards λ\u003csub\u003emax\u003c/sub\u003e 542 nm is observed, indicating an increase in particle size or aggregation. However, when comparing the λ\u003csub\u003emax\u003c/sub\u003e of the individual systems (533 nm Gelac, 535 nm Gelw, and 542 nm PEOac) to the λ\u003csub\u003emax\u003c/sub\u003e of the complete Gel/PEO-AuNPs system (λ\u003csub\u003emax\u003c/sub\u003e 532 nm), it is observed that the value is closer to the λ\u003csub\u003emax\u003c/sub\u003e value of the Gel system in the presence of acid. This effect can be attributed to the fact that Gel has a more significant influence on the reduction and mainly the stabilization of the particle through its functional groups [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e], in addition to the formation of fibers of only Gel and only PEO originating from solutions with different rheological properties. Therefore, when forming both the Taylor cone and the jet, and during the drying of the fiber towards the collector, it directly impacts the shape, size, and possible agglomeration.\u003c/p\u003e \u003cp\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCharacterization by FTIR was carried out on electrospun fibers of Gel-PEO both with and without the presence of AuNPs and on pristine materials. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e shows the results for both systems. This characterization aims to evaluate the interaction of AuNPs with the polymers.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe characteristic peak of 5a) PEO is found at 2873 cm\u003csup\u003e\u0026ndash;1\u003c/sup\u003e and is associated with the stretching of the aliphatic C-H group. Another minor band at 3300 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is associated with the terminal OH- vibration, while the peak at 1466 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e corresponds to a scissoring bending of -CH\u003csub\u003e2\u003c/sub\u003e. Additionally, the peak at 1340 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is associated with the wagging bending of -CH\u003csub\u003e2\u003c/sub\u003e, and the peak at 1085 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is related to C-O-C stretching. Likewise, the peak at 960 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is associated with the oscillation modes of -CH\u003csub\u003e2\u003c/sub\u003e-CH\u003csub\u003e2\u003c/sub\u003e and the vibration of C-O-C of PEO. Furthermore, in this spectrum, the amide I peak (C\u0026thinsp;=\u0026thinsp;O stretching) is evidenced at 1631 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, the amide II peak (NH bending) at 1525 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, the amide III peak (CN stretching plus NH in phase bending) at 1234 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, and the amide A peak (NH stretching vibration) at 3288 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, which are distinctive characteristics of gelatin 5b).[\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e], [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn the sample spectrum, characteristic bands of both polymers are observed. The interaction between PEO and gelatin is evidenced by the formation of a band of greater amplitude in the region of 3300 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, caused by the summation of the vibration of the -OH bands and the peak of amide A of both PEO and gelatin, suggesting the possible formation of hydrogen bonds between the two polymers. Additionally, other studies, such as the one reported by Rahma et al. in 2010, [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e] supports the miscibility between gelatin and PEO, showing the formation of hydrogen bonds between the ether groups of PEO and the amino groups of gelatin. In Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec) (PEO/Gel blank), subtle shifts in the positions of the amide-I and amide-II bands are observed, from 1631 to 1650 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and from 1525 to 1542 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively, compared to the pristine polymer. Furthermore, the hydrogen bonding of the amino group in gelatin and the hydrogen in PEO can act as electron donors and acceptors, resulting in a dipole-dipole interaction. [\u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSimilarly, in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed), the interaction of gelatin-PEO nanofibers with AuNPs is shown, where no changes in the intensity of the bands, shifts, or the formation of new bands are evident; this could be attributed to the fact that the interaction of AuNPs is closely linked to the amount of the gold precursor HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0 deposited; therefore, if the deposited amount is meager, it may not be sufficient to induce significant changes. Similarly, in 2017, Ahmed Al-Kattan et al.[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e], they reported the synthesis of nanofibers composed of chitosan and PEO with the addition of AuNPs, without any evidence of any effect on shape, intensity, or formation of additional bands to those of chitosan and PEO nanofibers after the incorporation of AuNPs. These results are similar to those reported in this work. Additionally, according to the reports of Manatunga et al., who in 2020 carried out the synthesis of gelatin and PEO fibers with the subsequent incorporation of gold nanoparticles (AuNPs), they maintain that no significant changes are observed in their material due to the overlap of signals between these materials [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eAn innovative, simple, and cost-effective method has been developed for synthesizing gold nanoparticles through the spontaneous reduction of HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0 by the electrospinning technique. This approach eliminates the need for additional synthesis steps once the precursor is loaded into the fibers and the application of heat or additional reducing agents. The reduction of gold ions in this method is influenced by three fundamental processes: I) the addition of acetic acid, which adjusts the pH value; II) the presence of reducing groups, such as the amino groups of gelatin; and III) the applied voltage during the electrospinning process. A distinctive feature of this approach is its ability to perform the entire process in a single step, meaning that the polymeric matrix is formed simultaneously with the gold nanoparticles, allowing their assembly and stabilization during the process. This method could pave the way for developing a new methodology to synthesize metal nanoparticles under specific conditions.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor Contribution.\u003c/strong\u003e GE, CC- Conceptualization, CC, AA, DIG, JZ, RL Methodology and Formal Analysis, GE,CC, JZ, GG- Writing (Original Draft).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding.\u003c/strong\u003e\u0026nbsp; This research work was funded by CONAHCyT \u0026nbsp;Fund Projects under grant no. (A1S8638).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e. The data that support the findings of this study are available from the corresponding author, Gethzemani Estrada-Villegas, upon reasonable request.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate The facts and views in the manuscript are solely ours, and we are totally responsible for authenticity, validity, and originality. We also declare that this manuscript is our original work, and we have not copied from anywhere else. There is no plagiarism in my manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication.\u003c/strong\u003e We undertake and agree that the manuscript submitted to your journal has not been published elsewhere and has not been simultaneously submitted to other journals.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests.\u003c/strong\u003e The authors declare no conflict of interest\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eH. Reza Ghorbani, M. Molaei -, A. Mary Ealias, and S. M. P, \u0026ldquo;A review on the classification, characterisation, synthesis of nanoparticles and their application Related content Synthesis of Aluminium Nanoparticles in A Water/Polyethylene Glycol Mixed Solvent using-EDM R.K. Sahu and Somashekhar S Hiremath-Particle pr\u0026rdquo;, doi: 10.1088/1757-899X/263/3/032019.\u003c/li\u003e\n\u003cli\u003eS. Kumar, P. Bhushan, and S. Bhattacharya, \u0026ldquo;Fabrication of Nanostructures with Bottom-up Approach and Their Utility in Diagnostics, Therapeutics, and Others,\u0026rdquo; \u003cem\u003eEnvironmental, Chemical and Medical Sensors\u003c/em\u003e, p. 167, 2018, doi: 10.1007/978-981-10-7751-7_8.\u003c/li\u003e\n\u003cli\u003eI. H. El-Sayed, X. Huang, and M. A. El-Sayed, \u0026ldquo;Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles,\u0026rdquo; \u003cem\u003eCancer Lett\u003c/em\u003e, vol. 239, no. 1, pp. 129\u0026ndash;135, Jul. 2006, doi: 10.1016/J.CANLET.2005.07.035.\u003c/li\u003e\n\u003cli\u003eM. Huang \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;Bragg reflectors; (140.3600) Lasers, tunable; (140.3070) Infrared and far-infrared lasers,\u0026rdquo; \u003cem\u003eNat. Photonics\u003c/em\u003e, vol. 17, no. 18, p. 10, 2009.\u003c/li\u003e\n\u003cli\u003eK. Esumi, N. Takei, and T. Yoshimura, \u0026ldquo;Antioxidant-potentiality of gold-chitosan nanocomposites,\u0026rdquo; \u003cem\u003eColloids Surf B Biointerfaces\u003c/em\u003e, vol. 32, no. 2, pp. 117\u0026ndash;123, Oct. 2003, doi: 10.1016/S0927-7765(03)00151-6.\u003c/li\u003e\n\u003cli\u003eN. O. Yakimovich, A. A. Ezhevskii, D. V. Guseinov, L. A. Smirnova, T. A. Gracheva, and K. S. Klychkov, \u0026ldquo;Antioxidant properties of gold nanoparticles studied by ESR spectroscopy,\u0026rdquo; \u003cem\u003eRussian Chemical Bulletin 2008 57:3\u003c/em\u003e, vol. 57, no. 3, pp. 520\u0026ndash;523, Mar. 2009, doi: 10.1007/S11172-008-0080-1.\u003c/li\u003e\n\u003cli\u003eK. J, D. Z, and K. BD, \u0026ldquo;Cryogenic CO2 formation on oxidized gold clusters synthesized via reactive layer assisted deposition,\u0026rdquo; \u003cem\u003eJ Am Chem Soc\u003c/em\u003e, vol. 127, no. 42, pp. 14592\u0026ndash;14593, Nov. 2005, doi: 10.1021/JA055764Z.\u003c/li\u003e\n\u003cli\u003eC. WS \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;Size-dependent tissue kinetics of PEG-coated gold nanoparticles,\u0026rdquo; \u003cem\u003eToxicol Appl Pharmacol\u003c/em\u003e, vol. 245, no. 1, pp. 116\u0026ndash;123, May 2010, doi: 10.1016/J.TAAP.2010.02.013.\u003c/li\u003e\n\u003cli\u003eS. Marx, M. V. Jose, J. D. Andersen, and A. J. Russell, \u0026ldquo;Electrospun gold nanofiber electrodes for biosensors,\u0026rdquo; \u003cem\u003eBiosens Bioelectron\u003c/em\u003e, vol. 26, no. 6, pp. 2981\u0026ndash;2986, Feb. 2011, doi: 10.1016/J.BIOS.2010.11.050.\u003c/li\u003e\n\u003cli\u003eP. Z. Chen and F. X. Gu, \u0026ldquo;Gold nanoparticles for colorimetric detection of pathogens,\u0026rdquo; \u003cem\u003eEncyclopedia of Biomedical Engineering\u003c/em\u003e, vol. 1\u0026ndash;3, pp. 108\u0026ndash;115, Jan. 2019, doi: 10.1016/B978-0-12-801238-3.99873-8.\u003c/li\u003e\n\u003cli\u003eE. Sapountzi, M. Braiek, F. Vocanson, J.-F. O. Chateaux, N. Jaffrezic-Renault, and F. Lagarde, \u0026ldquo;Gold nanoparticles assembly on electrospun poly(vinyl alcohol)/poly(ethyleneimine)/glucose oxidase nanofibers for ultrasensitive electrochemical glucose biosensing,\u0026rdquo; \u003cem\u003eSens Actuators B Chem\u003c/em\u003e, vol. 238, pp. 392\u0026ndash;401, 2017, doi: 10.1016/j.snb.2016.07.062.\u003c/li\u003e\n\u003cli\u003eA. D. Dwivedi and K. Gopal, \u0026ldquo;Biosynthesis of silver and gold nanoparticles using Chenopodium album leaf extract,\u0026rdquo; \u003cem\u003eColloids Surf A Physicochem Eng Asp\u003c/em\u003e, vol. 369, no. 1\u0026ndash;3, pp. 27\u0026ndash;33, Oct. 2010, doi: 10.1016/J.COLSURFA.2010.07.020.\u003c/li\u003e\n\u003cli\u003eJ. J. Zhang, M. M. Gu, T. T. Zheng, and J. J. Zhu, \u0026ldquo;Synthesis of gelatin-stabilized gold nanoparticles and assembly of carboxylic single-walled carbon nanotubes/Au composites for cytosensing and drug uptake,\u0026rdquo; \u003cem\u003eAnal Chem\u003c/em\u003e, vol. 81, no. 16, pp. 6641\u0026ndash;6648, Aug. 2009, doi: 10.1021/ac900628y.\u003c/li\u003e\n\u003cli\u003eH. Tyagi, A. Kushwaha, A. Kumar, and M. Aslam, \u0026ldquo;A Facile pH Controlled Citrate-Based Reduction Method for Gold Nanoparticle Synthesis at Room Temperature,\u0026rdquo; \u003cem\u003eNanoscale Res Lett\u003c/em\u003e, vol. 11, no. 1, Dec. 2016, doi: 10.1186/s11671-016-1576-5.\u003c/li\u003e\n\u003cli\u003eB. Contreras-Trigo \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;Slight pH Fluctuations in the Gold Nanoparticle Synthesis Process Influence the Performance of the Citrate Reduction Method,\u0026rdquo; \u003cem\u003eSensors (Basel)\u003c/em\u003e, vol. 18, no. 7, Jul. 2018, doi: 10.3390/S18072246.\u003c/li\u003e\n\u003cli\u003eS. S. R. Dasary, A. K. Singh, D. Senapati, H. Yu, and P. C. Ray, \u0026ldquo;Gold nanoparticle based label-free SERS probe for ultrasensitive and selective detection of trinitrotoluene,\u0026rdquo; \u003cem\u003eJ Am Chem Soc\u003c/em\u003e, vol. 131, no. 38, pp. 13806\u0026ndash;13812, 2009, doi: 10.1021/JA905134D.\u003c/li\u003e\n\u003cli\u003eN. N. Duy, D. T. T. Thao, H. T. D. Quy, D. Van Phu, B. D. Du, and nguyen Q. Hien, \u0026ldquo;Synthesis of gelatin stabilized gold nanoparticles with seed particles enlargement by gamma Co-60 irradiation,\u0026rdquo; \u003cem\u003eVietnam Journal of Chemistry\u003c/em\u003e, vol. 55, no. 2, p. 211, Apr. 2017, doi: 10.15625/2525-2321.2017-00446.\u003c/li\u003e\n\u003cli\u003eC.-C. Wu, D.-H. Chen, and W. G. Org, \u0026ldquo;Facile green synthesis of gold nanoparticles with gum arabic as a stabilizing agent and reducing agent,\u0026rdquo; \u003cem\u003eGold Bull\u003c/em\u003e, vol. 43, 2010, Accessed: Feb. 26, 2023. [Online]. Available: www.goldbulletin.org\u003c/li\u003e\n\u003cli\u003eN. N. Duy, D. X. Du, D. Van Phu, L. A. Quoc, B. D. Du, and N. Q. Hien, \u0026ldquo;Synthesis of gold nanoparticles with seed enlargement size by \u0026gamma;-irradiation and investigation of antioxidant activity,\u0026rdquo; \u003cem\u003eColloids Surf A Physicochem Eng Asp\u003c/em\u003e, vol. 436, pp. 633\u0026ndash;638, Sep. 2013, doi: 10.1016/J.COLSURFA.2013.07.038.\u003c/li\u003e\n\u003cli\u003eN. Q. Hien, D. Van Phu, N. N. Duy, and L. A. Quoc, \u0026ldquo;Radiation synthesis and characterization of hyaluronan capped gold nanoparticles,\u0026rdquo; \u003cem\u003eCarbohydr Polym\u003c/em\u003e, vol. 89, no. 2, pp. 537\u0026ndash;541, Jun. 2012, doi: 10.1016/J.CARBPOL.2012.03.041.\u003c/li\u003e\n\u003cli\u003eY. Huang, Y. Fang, L. Chen, A. Lu, and L. Zhang, \u0026ldquo;One-step synthesis of size-tunable gold nanoparticles immobilized on chitin nanofibrils via green pathway and their potential applications,\u0026rdquo; \u003cem\u003eChemical Engineering Journal\u003c/em\u003e, vol. 315, pp. 573\u0026ndash;582, 2017, doi: 10.1016/j.cej.2017.01.065.\u003c/li\u003e\n\u003cli\u003eJ. Bai \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;A simple and effective route for the preparation of poly(vinylalcohol) (PVA) nanofibers containing gold nanoparticles by electrospinning method,\u0026rdquo; \u003cem\u003eSolid State Commun\u003c/em\u003e, vol. 141, pp. 292\u0026ndash;295, 2007, doi: 10.1016/j.ssc.2006.10.024.\u003c/li\u003e\n\u003cli\u003eS. Shankar, L. Jaiswal, P. R. Selvakannan, K. S. Ham, and J. W. Rhim, \u0026ldquo;Gelatin-based dissolvable antibacterial films reinforced with metallic nanoparticles,\u0026rdquo; \u003cem\u003eRSC Adv\u003c/em\u003e, vol. 6, no. 71, pp. 67340\u0026ndash;67352, Jul. 2016, doi: 10.1039/C6RA10620J.\u003c/li\u003e\n\u003cli\u003eL. M. Duque S\u0026aacute;nchez, L. Rodriguez, and M. L\u0026oacute;pez, \u0026ldquo;Enero de 2013 Duque et al. Electrospinning 10,\u0026rdquo; 2014. Accessed: Apr. 06, 2019. [Online]. Available: http://www.ehu.eus/reviberpol/pdf/ENE13/duque.pdf\u003c/li\u003e\n\u003cli\u003eF. Topuz, M. A. Abdulhamid, T. Holtzl, and G. Szekely, \u0026ldquo;Nanofiber engineering of microporous polyimides through electrospinning: Influence of electrospinning parameters and salt addition,\u0026rdquo; \u003cem\u003eMater Des\u003c/em\u003e, vol. 198, p. 109280, 2021, doi: 10.1016/j.matdes.2020.109280.\u003c/li\u003e\n\u003cli\u003eN. Bhardwaj and S. C. Kundu, \u0026ldquo;Electrospinning: A fascinating fiber fabrication technique,\u0026rdquo; \u003cem\u003eBiotechnol Adv\u003c/em\u003e, vol. 28, no. 3, pp. 325\u0026ndash;347, 2010, doi: 10.1016/j.biotechadv.2010.01.004.\u003c/li\u003e\n\u003cli\u003e\u0026ldquo;Sci-Hub | Electrospinning of Nanofibers: Reinventing the Wheel? Advanced Materials, 16(14), 1151\u0026ndash;1170 | 10.1002/adma.200400719.\u0026rdquo; Accessed: Aug. 21, 2023. [Online]. Available: https://sci-hub.se/https://doi.org/10.1002/adma.200400719\u003c/li\u003e\n\u003cli\u003e\u0026ldquo;A Novel Approach to Prepare Gold Nanoparticles_Polyacrylamide Composite Nanofibers.pdf - Google Drive.\u0026rdquo;\u003c/li\u003e\n\u003cli\u003eY. Zhang \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;New gold nanostructures for sensor applications: A review,\u0026rdquo; \u003cem\u003eMaterials\u003c/em\u003e, vol. 7, no. 7, pp. 5169\u0026ndash;5201, 2014, doi: 10.3390/ma7075169.\u003c/li\u003e\n\u003cli\u003eP. Balashanmugam, G. Sucharithra, A. M. S., and T. S. A., \u0026ldquo;Efficacy of biopolymeric PVA-AuNPs and PCL-Curcumin loaded electrospun nanofibers and their anticancer activity against A431 skin cancer cell line,\u0026rdquo; \u003cem\u003eMater Today Commun\u003c/em\u003e, vol. 25, no. May, p. 101276, 2020, doi: 10.1016/j.mtcomm.2020.101276.\u003c/li\u003e\n\u003cli\u003eD. V. Havaldar, R. V. Patil, D. N. Moholkar, P. S. Magdum, A. P. Vadrale, and K. D. Pawar, \u0026ldquo;Differently synthesized gold nanoparticles respond differently to functionalization with L-amino acids,\u0026rdquo; \u003cem\u003eParticuology\u003c/em\u003e, vol. 52, pp. 97\u0026ndash;104, Oct. 2020, doi: 10.1016/J.PARTIC.2019.12.010.\u003c/li\u003e\n\u003cli\u003eT. M. Righi, R. S. Almeida, and M. A. d\u0026rsquo;\u0026Aacute;vila, \u0026ldquo;Electrospinning of Gelatin/PEO Blends: Influence of Process Parameters in the Nanofiber Properties,\u0026rdquo; \u003cem\u003eMacromol Symp\u003c/em\u003e, vol. 319, no. 1, pp. 230\u0026ndash;234, Sep. 2012, doi: 10.1002/MASY.201100137.\u003c/li\u003e\n\u003cli\u003eN. Amiri, Z. Rozbeh, T. Afrough, S. A. Sajadi Tabassi, A. Moradi, and J. Movaffagh, \u0026ldquo;Optimization of Chitosan-Gelatin Nanofibers Production: Investigating the Effect of Solution Properties and Working Parameters on Fibers Diameter,\u0026rdquo; \u003cem\u003eBionanoscience\u003c/em\u003e, vol. 8, no. 3, pp. 778\u0026ndash;789, Sep. 2018, doi: 10.1007/s12668-018-0540-5.\u003c/li\u003e\n\u003cli\u003eN. A. M. Barakat, M. A. Kanjwal, F. A. Sheikh, and H. Y. Kim, \u0026ldquo;Spider-net within the N6, PVA and PU electrospun nanofiber mats using salt addition: Novel strategy in the electrospinning process,\u0026rdquo; \u003cem\u003ePolymer (Guildf)\u003c/em\u003e, vol. 50, no. 18, pp. 4389\u0026ndash;4396, Aug. 2009, doi: 10.1016/J.POLYMER.2009.07.005.\u003c/li\u003e\n\u003cli\u003eV. P. Nirwan, A. Al-Kattan, A. Fahmi, and A. V Kabashin, \u0026ldquo;Fabrication of Stable Nanofiber Matrices for Tissue Engineering via Electrospinning of Bare Laser-Synthesized Au Nanoparticles in Solutions of High Molecular Weight Chitosan\u0026rdquo;, doi: 10.3390/nano9081058.\u003c/li\u003e\n\u003cli\u003eK. M. Nalin De Silva \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;royalsocietypublishing.org/journal/rsos Research Nanofibrous cosmetic face mask for transdermal delivery of nano gold: synthesis, characterization, release and zebra fish employed toxicity studies,\u0026rdquo; 2023, doi: 10.1098/rsos.201266.\u003c/li\u003e\n\u003cli\u003eL. Ge and J. Tang, \u0026ldquo;Synthesis of Hexagonal Gold Nanoparticles and Study of its Optical and Near-field Distribution Properties by Discrete Dipole Approximation,\u0026rdquo; in \u003cem\u003eJournal of Physics: Conference Series\u003c/em\u003e, IOP Publishing Ltd, Feb. 2022. doi: 10.1088/1742-6596/2185/1/012077.\u003c/li\u003e\n\u003cli\u003eM. A. R. Khan \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;A review on gold nanoparticles: Biological synthesis, characterizations, and analytical applications,\u0026rdquo; \u003cem\u003eResults in Chemistry\u003c/em\u003e, vol. 4. Elsevier B.V., Jan. 01, 2022. doi: 10.1016/j.rechem.2022.100478.\u003c/li\u003e\n\u003cli\u003eK. I. Requejo, A. V. Liopo, and E. R. Zubarev, \u0026ldquo;High yield synthesis and surface chemistry exchange of small gold hexagonal nanoprisms,\u0026rdquo; \u003cem\u003eChemical Communications\u003c/em\u003e, vol. 55, no. 76, pp. 11422\u0026ndash;11425, 2019, doi: 10.1039/C9CC04534A.\u003c/li\u003e\n\u003cli\u003eI. Saldan \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;Electrochemical synthesis and properties of gold nanomaterials,\u0026rdquo; \u003cem\u003eJournal of Solid State Electrochemistry\u003c/em\u003e, vol. 22, no. 3. Springer New York LLC, pp. 637\u0026ndash;656, Mar. 01, 2018. doi: 10.1007/s10008-017-3835-5.\u003c/li\u003e\n\u003cli\u003eP. G. Haro-Gonz\u0026aacute;lez, S. Ram\u0026iacute;rez-Rico, and E. R. Larios-Dur\u0026aacute;n, \u0026ldquo;ELECTROCHEMICAL SCIENCE Synthesis of Gold Nanoparticles in Aqueous Solutions by Electrochemical Reduction Using poly(ethylen glicol) as Stabilizer,\u0026rdquo; \u003cem\u003eInt. J. Electrochem. Sci\u003c/em\u003e, vol. 14, pp. 9704\u0026ndash;9710, 2019, doi: 10.20964/2019.10.10.\u003c/li\u003e\n\u003cli\u003eN. Saderi, M. Rajabi, B. Akbari, M. Firouzi, and Z. Hassannejad, \u0026ldquo;Fabrication and characterization of gold nanoparticle-doped electrospun PCL/chitosan nanofibrous scaffolds for nerve tissue engineering,\u0026rdquo; \u003cem\u003eJ Mater Sci Mater Med\u003c/em\u003e, vol. 29, no. 9, pp. 1\u0026ndash;10, Sep. 2018, doi: 10.1007/S10856-018-6144-3/FIGURES/5.\u003c/li\u003e\n\u003cli\u003eA. M. Abdelghany, E. M. Abdelrazek, S. I. Badr, M. S. Abdel-Aziz, and M. A. Morsi, \u0026ldquo;Effect of Gamma-irradiation on biosynthesized gold nanoparticles using Chenopodium murale leaf extract,\u0026rdquo; \u003cem\u003eJournal of Saudi Chemical Society\u003c/em\u003e, vol. 21, no. 5, pp. 528\u0026ndash;537, Jul. 2017, doi: 10.1016/j.jscs.2015.10.002.\u003c/li\u003e\n\u003cli\u003eM. P. Neupane \u003cem\u003eet al.\u003c/em\u003e, \u0026ldquo;Synthesis of gelatin-capped gold nanoparticles with variable gelatin concentration,\u0026rdquo; \u003cem\u003eJournal of Nanoparticle Research\u003c/em\u003e, vol. 13, no. 2, pp. 491\u0026ndash;498, Feb. 2011, doi: 10.1007/s11051-010-9971-9.\u003c/li\u003e\n\u003cli\u003eM. Borzenkov, G. Chirico, M. Collini, and P. Pallavicini, \u0026ldquo;Gold Nanoparticles for Tissue Engineering,\u0026rdquo; 2018, pp. 343\u0026ndash;390. doi: 10.1007/978-3-319-76090-2_10.\u003c/li\u003e\n\u003cli\u003eD. S. Dos Santos, P. J. G. Goulet, N. P. W. Pieczonka, O. N. Oliveira, and R. F. Aroca, \u0026ldquo;Gold nanoparticle embedded, self-sustained chitosan films as substrates for surface-enhanced Raman scattering,\u0026rdquo; \u003cem\u003eLangmuir\u003c/em\u003e, vol. 20, no. 23, pp. 10273\u0026ndash;10277, Nov. 2004, doi: 10.1021/la048328j.\u003c/li\u003e\n\u003cli\u003eR. M. Tripathi, S. Y. Yoon, D. Ahn, and S. J. Chung, \u0026ldquo;Facile Synthesis of Triangular and Hexagonal Anionic Gold Nanoparticles and Evaluation of Their Cytotoxicity,\u0026rdquo; \u003cem\u003eNanomaterials\u003c/em\u003e, vol. 9, no. 12, Dec. 2019, doi: 10.3390/NANO9121774.\u003c/li\u003e\n\u003cli\u003eS. Suarasan, M. Focsan, O. Soritau, D. Maniu, and S. Astilean, \u0026ldquo;One-pot, green synthesis of gold nanoparticles by gelatin and investigation of their biological effects on Osteoblast cells,\u0026rdquo; \u003cem\u003eColloids Surf B Biointerfaces\u003c/em\u003e, vol. 132, pp. 122\u0026ndash;131, Aug. 2015, doi: 10.1016/j.colsurfb.2015.05.009.\u003c/li\u003e\n\u003cli\u003eM. A. Rahman, M. A. Khan, and S. M. Tareq, \u0026ldquo;Preparation and Characterization of Polyethylene Oxide (PEO)/Gelatin Blend for Biomedical Application: Effect of Gamma Radiation,\u0026rdquo; \u003cem\u003eJ Appl Polym Sci\u003c/em\u003e, vol. 117, pp. 2075\u0026ndash;2082, 2010, doi: 10.1002/app.32034.\u003c/li\u003e\n\u003cli\u003eI. Yakimets, S. S. Paes, N. Wellner, A. C. Smith, R. H. Wilson, and J. R. Mitchell, \u0026ldquo;Effect of water content on the structural reorganization and elastic properties of biopolymer films: A comparative study,\u0026rdquo; \u003cem\u003eBiomacromolecules\u003c/em\u003e, vol. 8, no. 5, pp. 1710\u0026ndash;1722, May 2007, doi: 10.1021/BM070050X/ASSET/IMAGES/MEDIUM/BM070050XN00001.GIF.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"supplementary information","content":"\u003cp\u003esupplementary information is not available with this version\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"AuNPs, Nanofibers, Electrospinning, Gold reduction, Metal nanoparticles","lastPublishedDoi":"10.21203/rs.3.rs-4277652/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4277652/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThis study presents a new route for in situ synthesis of gold nanoparticles (AuNPs) and nanofibers using PEO-Gelatin as the supporting polymer via the electrospinning technique. Variation in the size and shape of the AuNPs significantly impacts their properties and applications, emphasizing the importance of precise methods for their synthesis. The proposed approach in this study aims to synthesize AuNPs and nanofibers simultaneously during the electrospinning process without the need for external reducing agents. This methodology offers significant advantages, such as conducting the reaction at room temperature while simultaneously synthesizing nanoparticles and fibers without requiring additional purification processes. The current work describes the synthesis conditions by adding chloroauric acid precursor (HAuCl\u003csub\u003e4\u003c/sub\u003e▪3H\u003csub\u003e2\u003c/sub\u003e0) to the polymer solution for electrospinning and in situ reduction at a voltage of 14 kV. Additionally, the morphology of the fibers and particles was explored using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), revealing hexagonal particles with an average size of 12 nm. The presence of AuNPs was confirmed via UV-Vis spectroscopy through Surface Plasmon Resonance (SPR) at λ\u003csub\u003emax\u003c/sub\u003e 532 nm. Finally, it was found that the precursor reduction is dependent on pH, polymer functional groups, and applied voltage.\u003c/p\u003e","manuscriptTitle":"A novel in situ AuNPs synthesis by electrospinning technique","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-23 19:04:16","doi":"10.21203/rs.3.rs-4277652/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4cf11188-f931-45d8-a059-40543b6b4599","owner":[],"postedDate":"April 23rd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-06T10:14:16+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-23 19:04:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4277652","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4277652","identity":"rs-4277652","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}