Electrospun hydrophobic nanofiber films from biodegradable zein and curcumin with improved tensile strength for air filtration

Electrospun hydrophobic nanofiber films from biodegradable zein and curcumin with improved tensile strength for air filtration | 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 Electrospun hydrophobic nanofiber films from biodegradable zein and curcumin with improved tensile strength for air filtration Shiyu Xie, Bo Xu, Li Yuan, Yaxin Zhao, Na Ma, Yaomin Wang, Dagang Liu, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1812451/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Zein as a natural protein had been widely used in various fields due to its biodegradability and biocompatibility. However, its sensitivity to humidity and poor mechanical performance limited its application in practice. In this study, zein-based composite nanofibers loaded with curcumin were prepared by electrospinning assisted with polyvinyl alcohol (PVA). The filtration efficiency of the modified nanofibers to the particles with diameters larger than 0.5 µm was all above 98%. The loaded curcumin interacted with protein molecular chains to form a network structure within tightly connected nanofibers, which exhibited excellent moisture resistance and good adhesion to cellulose paper towels used as air filter substrates. Meanwhile, its tensile strength had also been enhanced vastly to 0.72 MPa compared with the initial tensile strength of 0.21 MPa. This study provides a new electrospinning strategy for the preparation of zein-based composite nanofibers that can be widely utilized in air filtration with high moisture resistance. Zein Curcumin Electrospinning Hydrophobic Air filtration Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction With the rapid development of industrialization, the environmental problems caused by it are threatening human life and health, one of which is atmospheric particulate pollution[ 1 ]. Particulate matter (PM) can be divided into PM 2.5 and PM 10 according to particle size, representing particles less than 2.5 µm and 10 µm in diameter, respectively[ 2 ]. The main components of PM 2.5 are mineral dust, particulate organic matter (POM) and inorganic aerosols (combination of sulfate, nitrate and ammonium), and the secondary components are chloride salts, trace element oxides and potassium salts derived from biomass combustion[ 3 ]. PM 2.5 particles can penetrate the body's bronchi and lungs due to their small size. Each 10 µg/m 3 elevation in PM 2.5 was associated with approximately a 4%, 6%, and 8% increased risk of all cause, cardiopulmonary, and lung cancer mortality, respectively[ 3 ]. Long-term exposure to air pollutants is bound to lead to respiratory diseases such as asthma and chronic bronchitis, bacterial diseases, and an increased risk of cancer[ 4 ]. Hence, developing high efficiency multi-functional air filters with low air flow resistance has become an urgent challenge. Presently, the commonly used filtration materials on the market have large fiber aperture, which cannot effectively remove the fine particles and toxic gases in the air pollutants[ 5 ]. Electrospinning nanofibers have a large surface area to volume ratio, an adjustable porous structure, and a simple preparation process, making them an appropriate candidate for filtration materials[ 6 – 8 ]. The commonly used electrostatic spinning device is mainly composed of three parts: high voltage electrostatic generator, nozzle or metal needle and the receiving device[ 9 ]. The electric field formed by the high voltage power supply causes the spinning solution overcome the surface tension, form a jet, and gather on the surface of the receiving device to form nanofibers[ 10 ]. It has been reported that the electrospun nanofabrics as air filtration materials could effectively intercept fine particles and bacteria[ 11 ]. Fe 3 O 4 /polyacrylonitrile (PAN) magnetic nanofibers (MNFs) fabricated by electrospinning method were used for the remediation of phenol wastewater, achieved the removal efficiency of phenol to 85% in the first round use, and remained 52% of efficiency after 5 recycles using[ 12 ]. Researchers fabricated PAN/Ag composite nanofibers scaffold for their possible antimicrobial effect. The results showed the capability of PAN/Ag nanofibers scaffold to inhibit both Gram-positive ( Bacillus cereus ) and Gram-negative ( Escherichia coli ) bacterial growth[ 13 ]. Nowadays, traditional filtering materials used commercially are mainly petroleum-based polymers such as polyethylene and polypropylene, which are difficult to degrade and can cause secondary pollution after disposal, further polluting the environment[ 14 ]. Consequently, an increasing number of researchers turn their attention to renewable green raw materials[ 15 – 17 ], among which, protein as a natural compound has attracted much attention[ 18 – 20 ]. Zein, which is the main storage protein of maize seeds, has long been a subject of research for scientific interest as well as industrial applications. There are a lot of non-polar amino acids stored in zein, which make it a hydrophobic plant protein[ 21 ]. Its internal protein molecular chain has a multi-level structure, and denaturation can expose its internal hidden functional groups, interacting with air pollutants to achieve the effect of air filtration[ 22 ]. In our previous work, the hydrophobic and multifunctional zein nanofibers as efficient air filters had been prepared by electrospinning with the assistance of polyvinyl alcohol and poly(ethylene oxide), followed by cross-linking with glutaraldehyde. The prepared nanofibers exhibited a high removal rate of 0.1–10 µm particles[ 15 , 19 , 22 ]. However, the performance of pure zein nanofibers prepared by electrospinning is still insufficient for air filtration, especially for moisture resistance and limited strength. Curcumin is a natural polyphenol compound with low molecular weight, which exists in the rhizome of turmeric[ 23 ]. The structure of curcumin consists of two aromatic rings with methoxyl and hydroxyl groups at ortho, connected by a 7-carbon chain consisting of α , β -unsaturated β -diketone[ 24 ]. The molecular configuration of curcumin can exist in the tautomeric forming keto and enol due to intramolecular hydrogen atoms transfer at the β -diketone chain of curcumin. Curcumin has been proved to have health benefits, such as antioxidant[ 25 ], anti-inflammatory[ 26 ] and anti-cancer[ 27 ] properties, and has a great application prospect. In this work, by introducing curcumin with good compatibility with zein matrix as modifier, the composite nanofibers were prepared by electrospinning. It was found that the introduction of curcumin not only improved the filtration performance of nanofibers, but also improved the moisture resistance and mechanical properties of nanofibers. Thus, the weakness of mechanical properties and moisture sensitivity of zein-based materials was improved. 2. Experimental 2.1. Materials Zein was purchased from Shanghai Yuanye Bio-technology Co., Ltd (purity, 92%). PVA (217) with the viscosity of 20.5–24.5.0×10 − 3 Pa·s and alcoholysis degree of 87.0–89.0 mol/% was purchased from Kuraray Co., Ltd. (Japan). Acetic acid (99.9%) was purchased from Aladdin Reagent Database Co. (Shanghai, China). 2.2. Preparation of zein-based nanofibers 1 g PVA was dissolved in 9 g acetic acid solution (acetic acid / DI water = 8:2), followed by heating in a water bath at 90 ℃ for 1 hour to prepare 10% PVA solution. Meanwhile, curcumin with different mass fractions (0 wt.%, 0.4 wt.%,1 wt.%, 2 wt.%, 3 wt.%) was dissolved in 8.5g of acetic aqueous solution (acetic acid / DI water = 8:2). The prepared solution was stirred at constant temperature (room temperature) for 30 minutes, then 1.5 g of zein was added and stirred for another 90 minutes. After the PVA solution and zein solution were prepared (zein / PVA = 3:2), those two solutions were thoroughly mixed at constant temperature and magnetically stirred for 30 minutes, the electrospinning solution preparation was completed. The spinning solution was injected into a syringe with a volume of 10 mL and a needle diameter of 0.8 mm, and all the bubbles were completely drained. Then the syringe containing spinning liquid was fixed on a microsyringe pump, and the solution was spun into nanofibers by the action of electrostatic field. Nanofibers could be collected on a receiving device equipped with a paper towel by applying a high voltage power of 20 kV and a flow rate of 1.0 mL/h at 25 ± 2 ℃ and 30 ± 1% relative humidity. The distance from the receiver to the needle was 12 cm. Finally, the composite nanofiber films were dried at room temperature for 24 hours. The final obtained nanofiber films were yellow and became darker with the increase of curcumin content. The preparation process is shown in Fig. 1 . 2.3. Characterization Fourier transform infrared (FTIR) spectral analysis was performed using a Nicolet iN10 MX device (Thermo Fisher Scientific, US) in the wavenumber region of 4000 − 400 cm − 1 with a resolution of 4 cm − 1 . The secondary structure of the protein was counted by PeakFit software based on the FTIR data. The morphology of the fiber samples was observed using a scanning electron microscope (SEM) (Quanta FEG-250, FEI Co. Ltd., US) operating at an acceleration voltage of 10 kV. All the samples were sputter coated with gold before observing. The diameter of the nanofibers was measured using the Nano Measurer software, according to the SEM images of composite nanofibers. Then the nanofibers average diameter was calculated based on the diameter measurement of no less than 150 fibers in terms of the following equation: $${\stackrel{-}{d}}_{i}=\frac{{\varSigma }_{i=1}^{n}{d}_{i}}{n}$$ 1 Where \(\stackrel{-}{d}\) is the average diameter of the nanofiber; \({d}_{i}\) is the diameter of the i th nanofiber; n is the number of nanofibers in SEM image. The polluted air samples from burning joss sticks were diluted in a plastic bag to a level that could be measured by an analyzer because the initial concentration of pollutants was too high. The particle counter (CEM, DT-9881) was used to determine the concentrations of PM (different particle sizes from 0.3 to 10 µm) in the polluted air samples. A circular filter sample with a diameter of 37 mm was placed in a custom-made sample holder to perform air-filtration testing. The downstream air of the filter was collected in a clean vacuum gasbag and similar measurements were conducted. The air-filtration test was performed at 25 ℃ and 30% humidity, and the duration of each test was ca. 21 s. The static water contact angle was determined by contact shape analyzer OCA 35 (Data physics Instruments GmbH, Germany). A water (1 µL) droplet was deposited on the sample surface and the droplet shape was recorded. A CCD video camera and image analysis software were used to determine the contact angle. The experimental results were averaged for at least five measurements made on different areas of the sample surface. In order to test the water resistance of curcumin composite nanofibers, the composite nanofibers with varied content of curcumin (0%, 1% and 3%) were immersed in distilled water for different periods (0 h, 0.5 h and 1 h). After being removed from water, the excess water on the surface was sucked up with filter paper and dried for 12 h in a 60 ℃ oven. Then, the surface morphology was observed by scanning electron microscope. The mechanical properties of the films were analyzed using a testing machine (MTS systems China Co. Ltd.) in tensile mode according to the ISO 527-1:2012 standard at room temperature with an extension speed of 2 mm/min. 3. Results And Discussion 3.1. Structure and interaction To illustrate the structure, FTIR analysis was performed, and the spectra are shown in Fig. 2 A. Characteristic peaks at 1659 cm − 1 (zein amide I band), 1533 cm − 1 (zein amide II band) and 1260 cm − 1 (zein amide III band) corresponded to the stretching vibration of C = O in -CONH (I), the N-H bending vibration (II), the C-N stretching vibration and the N-H bending vibration (III), respectively. The peak presented at 1629 cm − 1 was assigned as the mixed peak of vibration of C = C and C = O; while peak at 1602 cm − 1 was determined as stretching vibrations of benzene ring; peak at 1429 cm − 1 was olefinic C-H bending vibration, peak at 1281 cm − 1 was aromatic C-O stretching vibrations[ 28 ]. The stretching vibration peak of the ketone group (1509 cm − 1 ) and the deformation peak of -NH (1028 cm − 1 ) were shifted to some extent when the curcumin content increased, indicating that curcumin interacted with the C = O and C-N groups in the protein subunit structure. There was a wider peak near 3300 cm − 1 in all the composite nanofibers, which was related to O-H stretching vibration of zein and curcumin. With the growth of curcumin content, all the peak patterns changed around 3300 cm − 1 , implying that there was hydrogen bond between zein and curcumin. It was proved that polyphenols could bind to some proteins through hydrogen bonding[ 28 , 29 ]. FTIR spectrum could provide effective information for studying the secondary structure of protein. It was generally acknowledged that the absorption peaks of different secondary structures such as α- helix, β -sheet, β -turn and random coil appear at different positions for the amide I band[ 20 ]. The peak at 1659 cm − 1 was distributed to the α -helix structure[ 30 ], and the band at 1620 cm − 1 was assigned to the β -sheet structure[ 31 ], which was thought to be related to the protein aggregation process[ 22 ]. The amount of β -sheet in the secondary structure of nanofibers decreased firstly after the addition of curcumin from Table. 1 and Fig. 2 C, which might indicate that no aggregates in the electrospun fibers. The peak at 1649 cm − 1 was attributed to the random coil[ 32 ], and its variation trend was similar to that of β -turn structure from Table. 1. This might be because the addition of curcumin made the network structure of composite nanofibers denser, resulting in the growth of intermolecular forces, and promoting the formation of β -turn structure. The interaction between curcumin and protein affected the secondary conformation of protein, and the increase of β -turn was also beneficial to the mechanical properties of the material. Table 1 Protein secondary structure ratio of nanofibers with various curcumin content in 1600–1700 cm − 1 . Sample / % β -sheet / % random coil / % β -turn / % 0 10.05 48.44 41.51 0.4 1.92 51.64 46.44 1.0 9.67 47.49 42.84 2.0 19.74 46.95 33.31 3.0 15.09 49.10 35.81 3.2. Morphology and air filtration performance Figure 3 A and B show the SEM images of nanofibers before and after filtration. For neat zein/PVA nanofibers without curcumin appeared as smooth cylindrical shape without microspheres and distributed uniformly with a fine diameter before filtration. With the increase of curcumin, the diameters of the nanofibers increased slightly. It could be noted that when curcumin content was above 1%, the increase of diameter was more obvious than below 1%. When curcumin content was 3%, the diameter of nanofibers increased to 1.17 µm compared with 0.75 µm of 0% curcumin. This might be due to the hydrogen bond formed between zein and curcumin, which elevated the viscosity of the spinning solution. Generally speaking, the increase of solution viscosity would result in the increase of nanofiber diameters. In order to investigate the effect of curcumin on filtration efficiency of composite nanofibers, filtration tests were carried out on systems with various curcumin content. After the air filtration test, a large number of pollution particles were absorbed on the surface of the nanofibers, and the particles closely bonded on the surface of the fiber to form a layer, which also showed a strong binding force with the fiber. The fibers were noticeably thicker. With the growth of curcumin content, growing numbers of pollutant particles precipitated on the surface of nanofibers. When the content of curcumin increased to 2%, nanofibers contaminated part of the shadow area was larger, more intensive, indicating that there was a better bonding force between nanofibers and particulate matter with the increase of curcumin, which could capture more pollutants and pollution particles and form dense layers on the surface of nanofibers. Figure 3 C and D show filtration efficiency of nanofibers with diverse curcumin content to varying particle size pollutants. In general, nanofibers without curcumin exhibited lowest removal efficiency for all particle sizes. This might be because the interactions between pollutants and nanofibers might not be enough[ 15 ]. The filtration efficiency of larger particle size was higher than that of smaller particle size. For particles with diameters larger than 0.5 µm, the filtration efficiency of nanofibers increased with the increase of curcumin content when curcumin content was less than 1%. Nevertheless, when the curcumin content was higher than 1%, the filtration efficiency tended to be stable with the increase of curcumin. For particles with small diameter (such as 0.3 µm), the filtration efficiency of nanofibers generally increased with the increase of curcumin content, but decreased slightly when curcumin content was 2%, mainly because the particle size was small and the pore size formed between nanofibers was larger than the particle size. In addition to the traditional filter system of diffusion, intercept and electrostatic deposition, hydrophobic groups such as glycine and charged groups such as lysine on proteins could facilitate adsorption of very small pollutants by interacting with pollutant particles, which might include chemical bonding, hydrogen bonding, electrostatic interaction, and hydrophobic interaction[ 22 , 33 ]. Curcumin, as a kind of phenolic compound, was a small molecular compound, that could occupy the space between protein molecules and form hydrogen bonds with the amino and hydroxyl groups of zein and polyvinyl alcohol molecules, resulting the structure of nanofibers more compact[ 34 ]. It was difficult for larger particulate pollutants in the air to pass through, enhancing filtration efficiency. 3.3. Hydrophobic analysis Figure 4 shows the static contact angle curve of composite nanofiber films with various curcumin contents and the surface morphology of nanofiber films after the contact angle test. The contact angle values of nanofiber films first increased and then decreased with the increase of curcumin. For neat zein/PVA nanofiber film without curcumin, the contact angle of the nanofiber film was 96.3°, and the surface of the nanofiber film was transparent after the contact angle test. The nanofiber morphology was completely destroyed by SEM observation as shown in Fig. 4 C. When the content of curcumin increased to 1%, the contact angle of the nanofiber film lifted to 110.1°. It could be seen from Fig. 4 D and E that the surface of the nanofiber with curcumin added swelled after the contact angle test, and the nanofiber diameter increased, but the fiber morphology was not completely destroyed. It mainly because with the increase of curcumin, the hydrogen bond interactions between curcumin and matrix could be strengthen the water stability of the nanofibers, thus improving the contact angle of the nanofiber film, and making the surface morphology more difficult to be destroyed. The contact angle of the nanofiber film gradually decreased and tended to balance while the content of curcumin was rising. When curcumin content was 3%, the contact angle slightly decreased to 99.5°. Nanofiber diameters were an important factor affecting the hydrophilicity of materials. The smaller the diameter of the nanofiber would result in the larger specific surface area. Nevertheless, there was a tendency that solid surfaces had adsorption properties to reduce surface energy. Therefore, the larger the specific surface area led to the stronger ability of absorbing water[ 35 ]. 3.4. Surface morphology of nanofibers after swelling The SEM images of composite nanofibers with different curcumin contents under gradient immersion time are presented in Fig. 5 . It could be seen that when the nanofibers with varied curcumin content were not soaked, the surface distribution was uniform and the morphology was well. After soaking the nanofibers in distilled water, the surface of the nanofibers with 0% curcumin swelled after soaking for 0.5 h, and the fiber structure almost disappeared after soaking for 1 h, mainly because the polyvinyl alcohol and zein molecular chain contained a large amount of hydrophilic polar groups. While with the increase of curcumin, the composite nanofibers were swelling, but not been completely destroyed under different soaking time. It has been shown that curcumin could improve the moisture resistance of nanofibers to some extent, which was mainly due to the strong hydrogen bonding interactions between curcumin and matrix could stabilize the matrix under high humid conditions. 3.5. Mechanical behaviors As could be seen from the tensile strength curve of nanofiber films in Fig. 6 A, with the increase of curcumin content, the tensile strength first increased and then decreased. The maximum value of the tensile strength of 0.72 MPa was obtained at 1% curcumin content compared with 0.21 MPa of films without curcumin. It mainly because when a small amount of curcumin was added, hydrogen bonding interactions would strengthen the network structure, and the tensile strength was improved when the external force was applied. When the content of curcumin was further increased, the diameter of the prepared nanofibers increased, the uniformity of diameter distribution of nanofibers decreased. In the process of tensile test, the finer fibers broke first, and then the larger fibers broke rapidly as a result of stress concentration, and could withstand less tension. As shown in Fig. 6 B, after tensile fracture, the nanofibers at 1% curcumin content became fine as a whole, but their ends became coarser. Because when a certain amount of curcumin was added, the interaction force between molecules increased, and it was not easy to slip between molecular chains. Under the action of external force, the molecular chain was fully extended and the fiber became fine, and the molecular chain curled and bounced back after breaking under the external force, resulting in the coarser end, indicating that the elasticity and toughness of nanofibers had been significantly improved. However, when the tensile strength of the composite nanofibers was low, the diameter of the nanofibers after tensile fracture did not change significantly compared with that before fracture, and there was no fracture elongation phenomenon at the end of the nanofibers, which belonged to brittle fracture. The digital images of the nanofiber films uncovered from the supporting material (paper towel) before and after adding curcumin were shown in Fig. 6 C. Firstly, it could be seen from the figure that the neat sample which was nanofiber film without curcumin was white, while the sample with curcumin was light yellow. But most importantly, the neat sample could retain its original shape when removed from the supporting material. However, the sample with curcumin tended to stick together and could not keep their original shape. This might be due to the large surface tension of the nanofiber films containing curcumin, on the one hand, it could effectively adsorb pollutants in the air; on the other hand, the surface tension of the filter material was too large to adhesion, and the specific surface area was easy to reduce in the process of use, while the convenience was lost. 4. Conclusion In this work, the composite nanofibers loaded with curcumin based on biodegradable zein and PVA with moisture resistance, mechanical properties and high filtration efficiency were successfully prepared by electrospinning. The loaded curcumin could interact with the protein molecular chain to form hydrogen bonds, making the nanofibers tightly connected, forming a network shape, enhancing the mechanical properties and adsorption capacity of pollutant particles. The filtration efficiency was more than 98% for pollutant particles larger than 0.5 µm, and the filtration efficiency was 95.6% for 0.3 µm. After filtering pollutants, the contaminated part of curcumin loaded nanofibers had a larger shadow area, forming a dense layer and having a better binding force with particle pollutants. The surface morphology of composite nanofibers was maintained under high humidity, indicating that nanofibers had high moisture stability. When the content of curcumin in nanofibers was 1%, the maximum contact angle reached 110.1° and the stability increased. Therefore, these composite nanofibers may become promising materials for combating air pollution. While meeting the current concept of green environmental protection and sustainable development, they have excellent comprehensive performance and wide application prospects. Declarations Acknowledgements This work was supported by the Beijing Natural Science Foundation (2202014) and open funding of Beijing Advanced Innovation Center for Food Nutrition and Human. Funding The authors have not disclosed any funding. Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Author Contribution Shiyu Xie wrote the manuscript. Huafeng Tian, Bo Xu, Dagang Liu, Aimin Xiang and Yuge Ouyang provided the idea and revised this manuscript. Li Yuan, Yaxin Zhao, Na Ma and Yaomin Wang assisted with the experiment. References Giles LV, Barn P, Kunzli N, Romieu I, Mittleman MA, van Eeden S, Allen R, Carlsten C, Stieb D, Noonan C, Smargiassi A, Kaufman JD, Hajat S, T KosatskyM Brauer (2011) From good intentions to proven interventions: effectiveness of actions to reduce the health impacts of air pollution. Environ Health Perspect 119(1):29–36 R M HarrisonJ X Yin (2000) Particulate matter in the atmosphere: which particle properties are important for its effects on health? Sci Total Environ 249(1–3):85–101 Zhang R, Jing J, Tao J, Hsu SC, Wang G, Cao J, Lee CSL, Zhu L, Chen Z, Shen YZhaoZ (2014) Chemical characterization and source apportionment of PM2.5 in Beijing: seasonal perspective (vol 13, pg 7053, 2013). ATMOSPHERIC CHEMISTRY AND PHYSICS 14(1):175–175 Santibanez-Andrade M, Chirino YI, Gonzalez-Ramirez I, Sanchez-PerezC Y, Garcia-Cuellar M (2020) Deciphering the Code between Air Pollution and Disease: The Effect of Particulate Matter on Cancer Hallmarks.INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES21(1) Xu J, Liu C, Hsu P-C, Liu K, Zhang R, Cui YLiuY (2016) Roll-to-Roll Transfer of Electrospun Nanofiber Film for High-Efficiency Transparent Air Filter. Nano Lett 16(2):1270–1275 Senthil Muthu Kumar T, Senthil Kumar K, Rajini N, Siengchin S, N AyrilmisA Varada Rajulu (2019) A comprehensive review of electrospun nanofibers: Food and packaging perspective.Composites Part B: Engineering175 He Y, Tian HF, Xiang AM, Ma SB, YinA DY, Rajulu V (2022) Fabrication of PVA/GO Nanofiber Films by Electrospinning: Application for the Adsorption of Cu2 + and Organic Dyes. J Polym Environ 30(7):2964–2975 Lu YR, Zhang W, Wang M, Zhang H, LiW JH, Luo H (2022) Fabrication of GO/PAN Nanofiber Membrane Grafted with Chitosan as Efficient Adsorbent for Dye Removal. JOURNAL OF POLYMERS AND THE ENVIRONMENT 30(7):2943–2954 AnjehS AM R Nabavi Preparation, Characterization and Properties of a Novel Electrospun Polyamide-6/ Chitosan/Graphene Oxide Composite Nanofiber.JOURNAL OF POLYMERS AND THE ENVIRONMENT Haider S, Al-Zeghayer Y, Ali FAA, Haider A, Mahmood A, Al-Masry WA, M ImranM O Aijaz (2013) Highly aligned narrow diameter chitosan electrospun nanofibers.JOURNAL OF POLYMER RESEARCH20(4) Li JL, Pan K, TianL HF, Yin J (2020) The Potential of Electrospinning/Electrospraying Technology in the Rational Design of Hydrogel Structures.MACROMOLECULAR MATERIALS AND ENGINEERING305(8) Li JL, Chen XY, XuK Pan DF (2019) Immobilization of horseradish peroxidase on electrospun magnetic nanofibers for phenol removal. Ecotoxicol Environ Saf 170:716–721 Haider A, HaiderI S, Kang K (2018) A comprehensive review summarizing the effect of electrospinning parameters and potential applications of nanofibers in biomedical and biotechnology. Arab J Chem 11(8):1165–1188 Cheng XQ, Wang ZX, Jiang X, Li TX, Lau CH, Guo ZH, Shao JMaL (2018) Towards sustainable ultrafast molecular-separation membranes: From conventional polymers to emerging materials. Prog Mater Sci 92:258–283 Li K, Li CM, Tian HF, Yuan L, Xiang AM, Wang CY, LiA V Rajulu (2020) J L Multifunctional and Efficient Air Filtration: A Natural Nanofilter Prepared with Zein and Polyvinyl Alcohol.MACROMOLECULAR MATERIALS AND ENGINEERING305(8) Deeksha B, Sadanand V, Rajulu NHariramAV (2021) Preparation and properties of cellulose nanocomposite fabrics with in situ generated silver nanoparticles by bioreduction method. J Bioresources Bioprod 6(1):75–81 Ashok B, Hariram N, Rajulu SSiengchinAV (2020) Modification of tamarind fruit shell powder with in situ generated copper nanoparticles by single step hydrothermal method. J Bioresources Bioprod 5(3):180–185 Liu X, Souzandeh H, Zheng Y, Xie Y, ZhongC W-H, Wang (2017) Soy protein isolate/bacterial cellulose composite membranes for high efficiency particulate air filtration. Compos Sci Technol 138:124–133 Tian HF, Fu XW, Zheng M, Wang Y, Li YC, XiangW AM, Zhong H (2018) Natural polypeptides treat pollution complex: Moisture-resistant multi-functional protein nanofabrics for sustainable air filtration. Nano Res 11(8):4265–4277 Y X WangL Y, Chen (2012) Electrospinning of Prolamin Proteins in Acetic Acid: The Effects of Protein Conformation and Aggregation in Solution. Macromol Mater Eng 297(9):902–913 Park JH, Park SM, Kim YH, Oh W, Lee GW, Karim MR, ParkJ JH, Yeum H (2013) Effect of montmorillonite on wettability and microstructure properties of zein/montmorillonite nanocomposite nanofiber mats. J Compos Mater 47(2):251–257 Yu X, Li CM, Tian HF, Yuan L, Xiang AM, Li JL, C Y WangA V Rajulu (2020) Hydrophobic cross-linked zein-based nanofibers with efficient air filtration and improved moisture stability.CHEMICAL ENGINEERING JOURNAL396 Chatzinasiou L, Booker A, MacLennan E, Heinrich MMackonochieM (2019) Turmeric (Curcuma longa L.) products: What quality differences exist?JOURNAL OF HERBAL MEDICINE17–18 Stohs SJ, Ji J, BucciH LR, Preuss G (2018) A Comparative Pharmacokinetic Assessment of a Novel Highly Bioavailable Curcumin Formulation with 95% Curcumin: A Randomized, Double-Blind, Crossover Study. JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 37(1):51–59 Kharat M, Skrzynski M, DeckerD EA, McClements J (2020) Enhancement of chemical stability of curcumin-enriched oil-in-water emulsions: Impact of antioxidant type and concentration. FOOD CHEMISTRY 320 Phumsuay R, Muangnoi C, Wasana PWD, Hasriadi O, Vajragupta PRojsitthisakP, Towiwat (2020) Molecular Insight into the Anti-Inflammatory Effects of the Curcumin Ester Prodrug Curcumin Diglutaric Acid In Vitro and In Vivo.INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES21(16) Moller K, Bein BMacaulayT (2021) Curcumin Encapsulated in Crosslinked Cyclodextrin Nanoparticles Enables Immediate Inhibition of Cell Growth and Efficient Killing of Cancer Cells. NANOMATERIALS 11(2):489 Li J, Shin GH, Lee IW, ChenH X, Park J (2016) Soluble starch formulated nanocomposite increases water solubility and stability of curcumin. Food Hydrocolloids 56:41–49 Rani P, Yu X, Liu HT, Li K, He Y, TianR Kumar HF (2021) Material, antibacterial and anticancer properties of natural polyphenols incorporated soy protein isolate: A review.EUROPEAN POLYMER JOURNAL152 Wang YX, YangL JQ, Chen Y (2015) Convenient Fabrication of Electrospun Prolamin Protein Delivery System with Three-Dimensional Shapeability and Resistance to Fouling. ACS APPLIED MATERIALS & INTERFACES 7(24):13422–13430 Mizutani Y, Matsumura Y, Imamura K, Mori KNakanishiT (2003) Effects of water activity and lipid addition on secondary structure of zein in powder systems. J Agric Food Chem 51(1):229–235 F SecundoN Guerrieri (2005) ATR-FT/IR Study on the Interactions between Gliadins and Dextrin and Their Effects on Protein Secondary Structure. J Agric Food Chem 53(5):1757–1764 Li P, Wang CY, ZhangF Wei YY (2014) Air Filtration in the Free Molecular Flow Regime: A Review of High-Efficiency Particulate Air Filters Based on Carbon Nanotubes. SMALL 10(22):4543–4561 Chen FP, LiC BS, Tang H (2015) Nanocomplexation between Curcumin and Soy Protein Isolate: Influence on Curcumin Stability/Bioaccessibility and in Vitro Protein Digestibility. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 63(13):3559–3569 Cui JX, Li FH, Wang YL, Zhang QL (2020) W J MaC B Huang Electrospun nanofiber membranes for wastewater treatment applications. SEPARATION AND PURIFICATION TECHNOLOGY 250 Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 05 Jul, 2022 Reviewers invited by journal 04 Jul, 2022 Editor assigned by journal 01 Jul, 2022 First submitted to journal 30 Jun, 2022 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1812451","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":118370283,"identity":"efa6a924-fad1-4edf-950c-350f537382db","order_by":0,"name":"Shiyu Xie","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Shiyu","middleName":"","lastName":"Xie","suffix":""},{"id":118370284,"identity":"60cffae4-5196-45b0-be8a-d3ebcf6b2f03","order_by":1,"name":"Bo Xu","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Xu","suffix":""},{"id":118370285,"identity":"cb5bc4e4-a682-47b1-a5aa-ddf16ed9cd62","order_by":2,"name":"Li Yuan","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"Yuan","suffix":""},{"id":118370286,"identity":"302f37cf-40f0-4d11-a5ad-cee6931870f4","order_by":3,"name":"Yaxin Zhao","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yaxin","middleName":"","lastName":"Zhao","suffix":""},{"id":118370287,"identity":"7482adbd-9e85-44ad-b82e-de36ddf0591f","order_by":4,"name":"Na Ma","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Na","middleName":"","lastName":"Ma","suffix":""},{"id":118370288,"identity":"8083361d-3763-46db-8029-0543c6b5374f","order_by":5,"name":"Yaomin Wang","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yaomin","middleName":"","lastName":"Wang","suffix":""},{"id":118370289,"identity":"496690d8-0200-4117-8258-aab007259814","order_by":6,"name":"Dagang Liu","email":"","orcid":"","institution":"Nanjing University of Information Science and Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Dagang","middleName":"","lastName":"Liu","suffix":""},{"id":118370290,"identity":"9fb77cbc-20d5-44e8-b1ff-e58058c85272","order_by":7,"name":"Aimin Xiang","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Aimin","middleName":"","lastName":"Xiang","suffix":""},{"id":118370291,"identity":"1e61adb8-2cf9-467d-944e-c28ec7725cfb","order_by":8,"name":"Yuge Ouyang","email":"","orcid":"","institution":"Beijing Technology and Business University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yuge","middleName":"","lastName":"Ouyang","suffix":""},{"id":118370292,"identity":"866fa9b0-86c6-49d3-8be4-5808ca35c346","order_by":9,"name":"Huafeng tian","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEklEQVRIiWNgGAWjYDACZjBi4AdixgeMDQwJDBIgYTbcOnigWiQbgLTBQaAWHoJaGBBa2CSI0mLPzvzscWGbnQS/dPu16o87GPLspXsMGD6UHWbgn92Aw2Fs5sYz25IlJOecKbtx8AxDMY/MGQPGGecOM0jcOYDLL2bSvG3MdQY3ctJuHGxjSOyRyDFg5m07zGAgkYBDC/s3oJZ6CXuglgK4lr94tfCAbDksYSCRfowBroURn5bDPGXSPOeOS0jcyGGWONsmUcxz51jBwZ5z6TwSN7BrYe8/vk2ap6xagn9G+sMPlW02eeyzmzc++FFmLcc/A7sWZAsNgAQ4UhgOMEBijBBgf0CEolEwCkbBKBiJAAD3u1aF047AMgAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0001-5123-3590","institution":"Beijing Technology and Business University","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Huafeng","middleName":"","lastName":"tian","suffix":""}],"badges":[],"createdAt":"2022-06-30 15:34:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1812451/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1812451/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":23598625,"identity":"0a948c10-98b9-4842-979b-a5d3ebc443cd","added_by":"auto","created_at":"2022-07-07 17:07:25","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":263514,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the preparation of electrospinning nanofibers.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/c60c924ed0006ce7919fdbb7.png"},{"id":23598626,"identity":"280b620f-5de6-420d-aebc-52f1e1ffaace","added_by":"auto","created_at":"2022-07-07 17:07:25","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":81919,"visible":true,"origin":"","legend":"\u003cp\u003eStructural characterization of nanofibers. \u003cstrong\u003e(A)\u003c/strong\u003e FTIR spectrum.\u003cstrong\u003e (B-F) \u003c/strong\u003eSecondary conformation of proteins in 1600-1700 cm\u003csup\u003e-1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/cfacce403e402320a1a40272.png"},{"id":23597970,"identity":"1f6e9dcd-2c08-457a-a77d-7a9e2f6857fb","added_by":"auto","created_at":"2022-07-07 16:57:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":569033,"visible":true,"origin":"","legend":"\u003cp\u003eMicromorphology and air filtration performance.\u003cstrong\u003e (A)\u003c/strong\u003e SEM images. \u003cstrong\u003e(B)\u003c/strong\u003e Average diameter of nanofibers before and after filtration. \u003cstrong\u003e(C-D) \u003c/strong\u003eFiltration efficiency of nanofibers for diverse particles.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/8d51ddb0cf85376211a07da8.png"},{"id":23597974,"identity":"9844d04b-0c62-4fbd-8f0d-3aa6f68bef41","added_by":"auto","created_at":"2022-07-07 16:57:25","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":682682,"visible":true,"origin":"","legend":"\u003cp\u003eHydrophobicity of composite nanofibers.\u003cstrong\u003e (A)\u003c/strong\u003e Contact angle. \u003cstrong\u003e(B)\u003c/strong\u003e Digital images. \u003cstrong\u003e(C-E)\u003c/strong\u003e SEM images of nanofiber films after contact angle test.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/815e437acd4be8f44a9c5e45.png"},{"id":23598499,"identity":"fdba352c-43eb-4cba-83af-efd226c71ed0","added_by":"auto","created_at":"2022-07-07 17:02:25","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1012103,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of nanofibers with various curcumin content soaked in water for gradient time.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/f239601f95455b31b22b973b.png"},{"id":23597975,"identity":"b7ff2dbf-8c74-453f-8c8a-e080844190f3","added_by":"auto","created_at":"2022-07-07 16:57:25","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":628345,"visible":true,"origin":"","legend":"\u003cp\u003eMechanical performance.\u003cstrong\u003e (A) \u003c/strong\u003eTensile strength. \u003cstrong\u003e(B)\u003c/strong\u003e Fracture morphology after the tensile test. \u003cstrong\u003e(C)\u003c/strong\u003e Digital images.\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/00e4cf7d1256407ec2e0e73f.png"},{"id":23598627,"identity":"f28eec58-8784-48a9-b1f9-31b7564ed586","added_by":"auto","created_at":"2022-07-07 17:07:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":308669,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1812451/v1/9a913850-673d-404c-810d-979e46b7bd23.pdf"}],"financialInterests":"","formattedTitle":"Electrospun hydrophobic nanofiber films from biodegradable zein and curcumin with improved tensile strength for air filtration","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eWith the rapid development of industrialization, the environmental problems caused by it are threatening human life and health, one of which is atmospheric particulate pollution[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Particulate matter (PM) can be divided into PM\u003csub\u003e2.5\u003c/sub\u003e and PM\u003csub\u003e10\u003c/sub\u003e according to particle size, representing particles less than 2.5 \u0026micro;m and 10 \u0026micro;m in diameter, respectively[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The main components of PM\u003csub\u003e2.5\u003c/sub\u003e are mineral dust, particulate organic matter (POM) and inorganic aerosols (combination of sulfate, nitrate and ammonium), and the secondary components are chloride salts, trace element oxides and potassium salts derived from biomass combustion[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. PM\u003csub\u003e2.5\u003c/sub\u003e particles can penetrate the body's bronchi and lungs due to their small size. Each 10 \u0026micro;g/m\u003csup\u003e3\u003c/sup\u003e elevation in PM\u003csub\u003e2.5\u003c/sub\u003e was associated with approximately a 4%, 6%, and 8% increased risk of all cause, cardiopulmonary, and lung cancer mortality, respectively[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Long-term exposure to air pollutants is bound to lead to respiratory diseases such as asthma and chronic bronchitis, bacterial diseases, and an increased risk of cancer[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Hence, developing high efficiency multi-functional air filters with low air flow resistance has become an urgent challenge.\u003c/p\u003e \u003cp\u003ePresently, the commonly used filtration materials on the market have large fiber aperture, which cannot effectively remove the fine particles and toxic gases in the air pollutants[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Electrospinning nanofibers have a large surface area to volume ratio, an adjustable porous structure, and a simple preparation process, making them an appropriate candidate for filtration materials[\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The commonly used electrostatic spinning device is mainly composed of three parts: high voltage electrostatic generator, nozzle or metal needle and the receiving device[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The electric field formed by the high voltage power supply causes the spinning solution overcome the surface tension, form a jet, and gather on the surface of the receiving device to form nanofibers[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. It has been reported that the electrospun nanofabrics as air filtration materials could effectively intercept fine particles and bacteria[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e/polyacrylonitrile (PAN) magnetic nanofibers (MNFs) fabricated by electrospinning method were used for the remediation of phenol wastewater, achieved the removal efficiency of phenol to 85% in the first round use, and remained 52% of efficiency after 5 recycles using[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Researchers fabricated PAN/Ag composite nanofibers scaffold for their possible antimicrobial effect. The results showed the capability of PAN/Ag nanofibers scaffold to inhibit both Gram-positive (\u003cem\u003eBacillus cereus\u003c/em\u003e) and Gram-negative (\u003cem\u003eEscherichia coli\u003c/em\u003e) bacterial growth[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eNowadays, traditional filtering materials used commercially are mainly petroleum-based polymers such as polyethylene and polypropylene, which are difficult to degrade and can cause secondary pollution after disposal, further polluting the environment[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Consequently, an increasing number of researchers turn their attention to renewable green raw materials[\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], among which, protein as a natural compound has attracted much attention[\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Zein, which is the main storage protein of maize seeds, has long been a subject of research for scientific interest as well as industrial applications. There are a lot of non-polar amino acids stored in zein, which make it a hydrophobic plant protein[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Its internal protein molecular chain has a multi-level structure, and denaturation can expose its internal hidden functional groups, interacting with air pollutants to achieve the effect of air filtration[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. In our previous work, the hydrophobic and multifunctional zein nanofibers as efficient air filters had been prepared by electrospinning with the assistance of polyvinyl alcohol and poly(ethylene oxide), followed by cross-linking with glutaraldehyde. The prepared nanofibers exhibited a high removal rate of 0.1\u0026ndash;10 \u0026micro;m particles[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. However, the performance of pure zein nanofibers prepared by electrospinning is still insufficient for air filtration, especially for moisture resistance and limited strength.\u003c/p\u003e \u003cp\u003eCurcumin is a natural polyphenol compound with low molecular weight, which exists in the rhizome of turmeric[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. The structure of curcumin consists of two aromatic rings with methoxyl and hydroxyl groups at ortho, connected by a 7-carbon chain consisting of \u003cem\u003eα\u003c/em\u003e, \u003cem\u003eβ\u003c/em\u003e-unsaturated \u003cem\u003eβ\u003c/em\u003e-diketone[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The molecular configuration of curcumin can exist in the tautomeric forming keto and enol due to intramolecular hydrogen atoms transfer at the \u003cem\u003eβ\u003c/em\u003e-diketone chain of curcumin. Curcumin has been proved to have health benefits, such as antioxidant[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], anti-inflammatory[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] and anti-cancer[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] properties, and has a great application prospect.\u003c/p\u003e \u003cp\u003eIn this work, by introducing curcumin with good compatibility with zein matrix as modifier, the composite nanofibers were prepared by electrospinning. It was found that the introduction of curcumin not only improved the filtration performance of nanofibers, but also improved the moisture resistance and mechanical properties of nanofibers. Thus, the weakness of mechanical properties and moisture sensitivity of zein-based materials was improved.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Materials\u003c/h2\u003e \u003cp\u003eZein was purchased from Shanghai Yuanye Bio-technology Co., Ltd (purity, 92%). PVA (217) with the viscosity of 20.5\u0026ndash;24.5.0\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e Pa\u0026middot;s and alcoholysis degree of 87.0\u0026ndash;89.0 mol/% was purchased from Kuraray Co., Ltd. (Japan). Acetic acid (99.9%) was purchased from Aladdin Reagent Database Co. (Shanghai, China).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Preparation of zein-based nanofibers\u003c/h2\u003e \u003cp\u003e1 g PVA was dissolved in 9 g acetic acid solution (acetic acid / DI water\u0026thinsp;=\u0026thinsp;8:2), followed by heating in a water bath at 90 ℃ for 1 hour to prepare 10% PVA solution. Meanwhile, curcumin with different mass fractions (0 wt.%, 0.4 wt.%,1 wt.%, 2 wt.%, 3 wt.%) was dissolved in 8.5g of acetic aqueous solution (acetic acid / DI water\u0026thinsp;=\u0026thinsp;8:2). The prepared solution was stirred at constant temperature (room temperature) for 30 minutes, then 1.5 g of zein was added and stirred for another 90 minutes. After the PVA solution and zein solution were prepared (zein / PVA\u0026thinsp;=\u0026thinsp;3:2), those two solutions were thoroughly mixed at constant temperature and magnetically stirred for 30 minutes, the electrospinning solution preparation was completed. The spinning solution was injected into a syringe with a volume of 10 mL and a needle diameter of 0.8 mm, and all the bubbles were completely drained. Then the syringe containing spinning liquid was fixed on a microsyringe pump, and the solution was spun into nanofibers by the action of electrostatic field. Nanofibers could be collected on a receiving device equipped with a paper towel by applying a high voltage power of 20 kV and a flow rate of 1.0 mL/h at 25\u0026thinsp;\u0026plusmn;\u0026thinsp;2 ℃ and 30\u0026thinsp;\u0026plusmn;\u0026thinsp;1% relative humidity. The distance from the receiver to the needle was 12 cm. Finally, the composite nanofiber films were dried at room temperature for 24 hours. The final obtained nanofiber films were yellow and became darker with the increase of curcumin content. The preparation process is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. Characterization\u003c/h2\u003e \u003cp\u003eFourier transform infrared (FTIR) spectral analysis was performed using a Nicolet iN10 MX device (Thermo Fisher Scientific, US) in the wavenumber region of 4000\u0026thinsp;\u0026minus;\u0026thinsp;400 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e with a resolution of 4 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The secondary structure of the protein was counted by PeakFit software based on the FTIR data.\u003c/p\u003e \u003cp\u003eThe morphology of the fiber samples was observed using a scanning electron microscope (SEM) (Quanta FEG-250, FEI Co. Ltd., US) operating at an acceleration voltage of 10 kV. All the samples were sputter coated with gold before observing. The diameter of the nanofibers was measured using the Nano Measurer software, according to the SEM images of composite nanofibers. Then the nanofibers average diameter was calculated based on the diameter measurement of no less than 150 fibers in terms of the following equation:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$${\\stackrel{-}{d}}_{i}=\\frac{{\\varSigma }_{i=1}^{n}{d}_{i}}{n}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\stackrel{-}{d}\\)\u003c/span\u003e\u003c/span\u003e is the average diameter of the nanofiber; \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({d}_{i}\\)\u003c/span\u003e\u003c/span\u003e is the diameter of the \u003cem\u003ei\u003c/em\u003e th nanofiber; n is the number of nanofibers in SEM image.\u003c/p\u003e \u003cp\u003eThe polluted air samples from burning joss sticks were diluted in a plastic bag to a level that could be measured by an analyzer because the initial concentration of pollutants was too high. The particle counter (CEM, DT-9881) was used to determine the concentrations of PM (different particle sizes from 0.3 to 10 \u0026micro;m) in the polluted air samples. A circular filter sample with a diameter of 37 mm was placed in a custom-made sample holder to perform air-filtration testing. The downstream air of the filter was collected in a clean vacuum gasbag and similar measurements were conducted. The air-filtration test was performed at 25 ℃ and 30% humidity, and the duration of each test was ca. 21 s.\u003c/p\u003e \u003cp\u003eThe static water contact angle was determined by contact shape analyzer OCA 35 (Data physics Instruments GmbH, Germany). A water (1 \u0026micro;L) droplet was deposited on the sample surface and the droplet shape was recorded. A CCD video camera and image analysis software were used to determine the contact angle. The experimental results were averaged for at least five measurements made on different areas of the sample surface.\u003c/p\u003e \u003cp\u003eIn order to test the water resistance of curcumin composite nanofibers, the composite nanofibers with varied content of curcumin (0%, 1% and 3%) were immersed in distilled water for different periods (0 h, 0.5 h and 1 h). After being removed from water, the excess water on the surface was sucked up with filter paper and dried for 12 h in a 60 ℃ oven. Then, the surface morphology was observed by scanning electron microscope.\u003c/p\u003e \u003cp\u003eThe mechanical properties of the films were analyzed using a testing machine (MTS systems China Co. Ltd.) in tensile mode according to the ISO 527-1:2012 standard at room temperature with an extension speed of 2 mm/min.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results And Discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Structure and interaction\u003c/h2\u003e \u003cp\u003eTo illustrate the structure, FTIR analysis was performed, and the spectra are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA. Characteristic peaks at 1659 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (zein amide I band), 1533 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (zein amide II band) and 1260 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e (zein amide III band) corresponded to the stretching vibration of C\u0026thinsp;=\u0026thinsp;O in -CONH (I), the N-H bending vibration (II), the C-N stretching vibration and the N-H bending vibration (III), respectively. The peak presented at 1629 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was assigned as the mixed peak of vibration of C\u0026thinsp;=\u0026thinsp;C and C\u0026thinsp;=\u0026thinsp;O; while peak at 1602 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was determined as stretching vibrations of benzene ring; peak at 1429 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was olefinic C-H bending vibration, peak at 1281 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was aromatic C-O stretching vibrations[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. The stretching vibration peak of the ketone group (1509 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) and the deformation peak of -NH (1028 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) were shifted to some extent when the curcumin content increased, indicating that curcumin interacted with the C\u0026thinsp;=\u0026thinsp;O and C-N groups in the protein subunit structure. There was a wider peak near 3300 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e in all the composite nanofibers, which was related to O-H stretching vibration of zein and curcumin. With the growth of curcumin content, all the peak patterns changed around 3300 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, implying that there was hydrogen bond between zein and curcumin. It was proved that polyphenols could bind to some proteins through hydrogen bonding[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFTIR spectrum could provide effective information for studying the secondary structure of protein. It was generally acknowledged that the absorption peaks of different secondary structures such as \u003cem\u003eα-\u003c/em\u003ehelix, \u003cem\u003eβ\u003c/em\u003e-sheet, \u003cem\u003eβ\u003c/em\u003e-turn and random coil appear at different positions for the amide I band[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The peak at 1659 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was distributed to the \u003cem\u003eα\u003c/em\u003e-helix structure[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], and the band at 1620 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was assigned to the \u003cem\u003eβ\u003c/em\u003e-sheet structure[\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e], which was thought to be related to the protein aggregation process[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The amount of \u003cem\u003eβ\u003c/em\u003e-sheet in the secondary structure of nanofibers decreased firstly after the addition of curcumin from Table. 1 and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC, which might indicate that no aggregates in the electrospun fibers. The peak at 1649 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e was attributed to the random coil[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], and its variation trend was similar to that of \u003cem\u003eβ\u003c/em\u003e-turn structure from Table. 1. This might be because the addition of curcumin made the network structure of composite nanofibers denser, resulting in the growth of intermolecular forces, and promoting the formation of \u003cem\u003eβ\u003c/em\u003e-turn structure. The interaction between curcumin and protein affected the secondary conformation of protein, and the increase of \u003cem\u003eβ\u003c/em\u003e-turn was also beneficial to the mechanical properties of the material.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eProtein secondary structure ratio of nanofibers with various curcumin content in 1600\u0026ndash;1700 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSample / %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003eβ\u003c/em\u003e-sheet / %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003erandom coil / %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eβ\u003c/em\u003e-turn / %\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e10.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e48.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e41.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e51.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e46.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e9.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e42.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e19.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e46.95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e33.31\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e49.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e35.81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Morphology and air filtration performance\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA and B show the SEM images of nanofibers before and after filtration. For neat zein/PVA nanofibers without curcumin appeared as smooth cylindrical shape without microspheres and distributed uniformly with a fine diameter before filtration. With the increase of curcumin, the diameters of the nanofibers increased slightly. It could be noted that when curcumin content was above 1%, the increase of diameter was more obvious than below 1%. When curcumin content was 3%, the diameter of nanofibers increased to 1.17 \u0026micro;m compared with 0.75 \u0026micro;m of 0% curcumin. This might be due to the hydrogen bond formed between zein and curcumin, which elevated the viscosity of the spinning solution. Generally speaking, the increase of solution viscosity would result in the increase of nanofiber diameters.\u003c/p\u003e \u003cp\u003eIn order to investigate the effect of curcumin on filtration efficiency of composite nanofibers, filtration tests were carried out on systems with various curcumin content. After the air filtration test, a large number of pollution particles were absorbed on the surface of the nanofibers, and the particles closely bonded on the surface of the fiber to form a layer, which also showed a strong binding force with the fiber. The fibers were noticeably thicker. With the growth of curcumin content, growing numbers of pollutant particles precipitated on the surface of nanofibers. When the content of curcumin increased to 2%, nanofibers contaminated part of the shadow area was larger, more intensive, indicating that there was a better bonding force between nanofibers and particulate matter with the increase of curcumin, which could capture more pollutants and pollution particles and form dense layers on the surface of nanofibers.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC and D show filtration efficiency of nanofibers with diverse curcumin content to varying particle size pollutants. In general, nanofibers without curcumin exhibited lowest removal efficiency for all particle sizes. This might be because the interactions between pollutants and nanofibers might not be enough[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The filtration efficiency of larger particle size was higher than that of smaller particle size. For particles with diameters larger than 0.5 \u0026micro;m, the filtration efficiency of nanofibers increased with the increase of curcumin content when curcumin content was less than 1%. Nevertheless, when the curcumin content was higher than 1%, the filtration efficiency tended to be stable with the increase of curcumin. For particles with small diameter (such as 0.3 \u0026micro;m), the filtration efficiency of nanofibers generally increased with the increase of curcumin content, but decreased slightly when curcumin content was 2%, mainly because the particle size was small and the pore size formed between nanofibers was larger than the particle size. In addition to the traditional filter system of diffusion, intercept and electrostatic deposition, hydrophobic groups such as glycine and charged groups such as lysine on proteins could facilitate adsorption of very small pollutants by interacting with pollutant particles, which might include chemical bonding, hydrogen bonding, electrostatic interaction, and hydrophobic interaction[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. Curcumin, as a kind of phenolic compound, was a small molecular compound, that could occupy the space between protein molecules and form hydrogen bonds with the amino and hydroxyl groups of zein and polyvinyl alcohol molecules, resulting the structure of nanofibers more compact[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. It was difficult for larger particulate pollutants in the air to pass through, enhancing filtration efficiency.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Hydrophobic analysis\u003c/h2\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows the static contact angle curve of composite nanofiber films with various curcumin contents and the surface morphology of nanofiber films after the contact angle test. The contact angle values of nanofiber films first increased and then decreased with the increase of curcumin. For neat zein/PVA nanofiber film without curcumin, the contact angle of the nanofiber film was 96.3\u0026deg;, and the surface of the nanofiber film was transparent after the contact angle test. The nanofiber morphology was completely destroyed by SEM observation as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eC.\u003c/p\u003e \u003cp\u003eWhen the content of curcumin increased to 1%, the contact angle of the nanofiber film lifted to 110.1\u0026deg;. It could be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eD and E that the surface of the nanofiber with curcumin added swelled after the contact angle test, and the nanofiber diameter increased, but the fiber morphology was not completely destroyed. It mainly because with the increase of curcumin, the hydrogen bond interactions between curcumin and matrix could be strengthen the water stability of the nanofibers, thus improving the contact angle of the nanofiber film, and making the surface morphology more difficult to be destroyed. The contact angle of the nanofiber film gradually decreased and tended to balance while the content of curcumin was rising.\u003c/p\u003e \u003cp\u003eWhen curcumin content was 3%, the contact angle slightly decreased to 99.5\u0026deg;. Nanofiber diameters were an important factor affecting the hydrophilicity of materials. The smaller the diameter of the nanofiber would result in the larger specific surface area. Nevertheless, there was a tendency that solid surfaces had adsorption properties to reduce surface energy. Therefore, the larger the specific surface area led to the stronger ability of absorbing water[\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Surface morphology of nanofibers after swelling\u003c/h2\u003e \u003cp\u003eThe SEM images of composite nanofibers with different curcumin contents under gradient immersion time are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. It could be seen that when the nanofibers with varied curcumin content were not soaked, the surface distribution was uniform and the morphology was well. After soaking the nanofibers in distilled water, the surface of the nanofibers with 0% curcumin swelled after soaking for 0.5 h, and the fiber structure almost disappeared after soaking for 1 h, mainly because the polyvinyl alcohol and zein molecular chain contained a large amount of hydrophilic polar groups. While with the increase of curcumin, the composite nanofibers were swelling, but not been completely destroyed under different soaking time. It has been shown that curcumin could improve the moisture resistance of nanofibers to some extent, which was mainly due to the strong hydrogen bonding interactions between curcumin and matrix could stabilize the matrix under high humid conditions.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.5. Mechanical behaviors\u003c/h2\u003e \u003cp\u003eAs could be seen from the tensile strength curve of nanofiber films in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eA, with the increase of curcumin content, the tensile strength first increased and then decreased. The maximum value of the tensile strength of 0.72 MPa was obtained at 1% curcumin content compared with 0.21 MPa of films without curcumin. It mainly because when a small amount of curcumin was added, hydrogen bonding interactions would strengthen the network structure, and the tensile strength was improved when the external force was applied. When the content of curcumin was further increased, the diameter of the prepared nanofibers increased, the uniformity of diameter distribution of nanofibers decreased. In the process of tensile test, the finer fibers broke first, and then the larger fibers broke rapidly as a result of stress concentration, and could withstand less tension.\u003c/p\u003e \u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eB, after tensile fracture, the nanofibers at 1% curcumin content became fine as a whole, but their ends became coarser. Because when a certain amount of curcumin was added, the interaction force between molecules increased, and it was not easy to slip between molecular chains. Under the action of external force, the molecular chain was fully extended and the fiber became fine, and the molecular chain curled and bounced back after breaking under the external force, resulting in the coarser end, indicating that the elasticity and toughness of nanofibers had been significantly improved. However, when the tensile strength of the composite nanofibers was low, the diameter of the nanofibers after tensile fracture did not change significantly compared with that before fracture, and there was no fracture elongation phenomenon at the end of the nanofibers, which belonged to brittle fracture.\u003c/p\u003e \u003cp\u003eThe digital images of the nanofiber films uncovered from the supporting material (paper towel) before and after adding curcumin were shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eC. Firstly, it could be seen from the figure that the neat sample which was nanofiber film without curcumin was white, while the sample with curcumin was light yellow. But most importantly, the neat sample could retain its original shape when removed from the supporting material. However, the sample with curcumin tended to stick together and could not keep their original shape. This might be due to the large surface tension of the nanofiber films containing curcumin, on the one hand, it could effectively adsorb pollutants in the air; on the other hand, the surface tension of the filter material was too large to adhesion, and the specific surface area was easy to reduce in the process of use, while the convenience was lost.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn this work, the composite nanofibers loaded with curcumin based on biodegradable zein and PVA with moisture resistance, mechanical properties and high filtration efficiency were successfully prepared by electrospinning. The loaded curcumin could interact with the protein molecular chain to form hydrogen bonds, making the nanofibers tightly connected, forming a network shape, enhancing the mechanical properties and adsorption capacity of pollutant particles. The filtration efficiency was more than 98% for pollutant particles larger than 0.5 \u0026micro;m, and the filtration efficiency was 95.6% for 0.3 \u0026micro;m. After filtering pollutants, the contaminated part of curcumin loaded nanofibers had a larger shadow area, forming a dense layer and having a better binding force with particle pollutants. The surface morphology of composite nanofibers was maintained under high humidity, indicating that nanofibers had high moisture stability. When the content of curcumin in nanofibers was 1%, the maximum contact angle reached 110.1\u0026deg; and the stability increased. Therefore, these composite nanofibers may become promising materials for combating air pollution. While meeting the current concept of green environmental protection and sustainable development, they have excellent comprehensive performance and wide application prospects.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Beijing Natural Science Foundation (2202014) and open funding of Beijing Advanced Innovation Center for Food Nutrition and Human.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have not disclosed any funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eShiyu Xie wrote the manuscript. Huafeng Tian, Bo Xu, Dagang Liu, Aimin Xiang and Yuge Ouyang provided the idea and revised this manuscript. Li Yuan, Yaxin Zhao, Na Ma and Yaomin Wang assisted with the experiment.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGiles LV, Barn P, Kunzli N, Romieu I, Mittleman MA, van Eeden S, Allen R, Carlsten C, Stieb D, Noonan C, Smargiassi A, Kaufman JD, Hajat S, T KosatskyM Brauer (2011) From good intentions to proven interventions: effectiveness of actions to reduce the health impacts of air pollution. Environ Health Perspect 119(1):29\u0026ndash;36\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eR M HarrisonJ X Yin (2000) Particulate matter in the atmosphere: which particle properties are important for its effects on health? Sci Total Environ 249(1\u0026ndash;3):85\u0026ndash;101\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang R, Jing J, Tao J, Hsu SC, Wang G, Cao J, Lee CSL, Zhu L, Chen Z, Shen YZhaoZ (2014) Chemical characterization and source apportionment of PM2.5 in Beijing: seasonal perspective (vol\u0026nbsp;13, pg 7053, 2013). ATMOSPHERIC CHEMISTRY AND PHYSICS 14(1):175\u0026ndash;175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSantibanez-Andrade M, Chirino YI, Gonzalez-Ramirez I, Sanchez-PerezC Y, Garcia-Cuellar M (2020) Deciphering the Code between Air Pollution and Disease: The Effect of Particulate Matter on Cancer Hallmarks.INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES21(1)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu J, Liu C, Hsu P-C, Liu K, Zhang R, Cui YLiuY (2016) Roll-to-Roll Transfer of Electrospun Nanofiber Film for High-Efficiency Transparent Air Filter. Nano Lett 16(2):1270\u0026ndash;1275\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSenthil Muthu Kumar T, Senthil Kumar K, Rajini N, Siengchin S, N AyrilmisA Varada Rajulu (2019) A comprehensive review of electrospun nanofibers: Food and packaging perspective.Composites Part B: Engineering175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe Y, Tian HF, Xiang AM, Ma SB, YinA DY, Rajulu V (2022) Fabrication of PVA/GO Nanofiber Films by Electrospinning: Application for the Adsorption of Cu2 + and Organic Dyes. J Polym Environ 30(7):2964\u0026ndash;2975\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLu YR, Zhang W, Wang M, Zhang H, LiW JH, Luo H (2022) Fabrication of GO/PAN Nanofiber Membrane Grafted with Chitosan as Efficient Adsorbent for Dye Removal. JOURNAL OF POLYMERS AND THE ENVIRONMENT 30(7):2943\u0026ndash;2954\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnjehS AM R Nabavi Preparation, Characterization and Properties of a Novel Electrospun Polyamide-6/ Chitosan/Graphene Oxide Composite Nanofiber.JOURNAL OF POLYMERS AND THE ENVIRONMENT\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaider S, Al-Zeghayer Y, Ali FAA, Haider A, Mahmood A, Al-Masry WA, M ImranM O Aijaz (2013) Highly aligned narrow diameter chitosan electrospun nanofibers.JOURNAL OF POLYMER RESEARCH20(4)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi JL, Pan K, TianL HF, Yin J (2020) The Potential of Electrospinning/Electrospraying Technology in the Rational Design of Hydrogel Structures.MACROMOLECULAR MATERIALS AND ENGINEERING305(8)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi JL, Chen XY, XuK Pan DF (2019) Immobilization of horseradish peroxidase on electrospun magnetic nanofibers for phenol removal. Ecotoxicol Environ Saf 170:716\u0026ndash;721\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaider A, HaiderI S, Kang K (2018) A comprehensive review summarizing the effect of electrospinning parameters and potential applications of nanofibers in biomedical and biotechnology. Arab J Chem 11(8):1165\u0026ndash;1188\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCheng XQ, Wang ZX, Jiang X, Li TX, Lau CH, Guo ZH, Shao JMaL (2018) Towards sustainable ultrafast molecular-separation membranes: From conventional polymers to emerging materials. Prog Mater Sci 92:258\u0026ndash;283\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi K, Li CM, Tian HF, Yuan L, Xiang AM, Wang CY, LiA V Rajulu (2020) J L Multifunctional and Efficient Air Filtration: A Natural Nanofilter Prepared with Zein and Polyvinyl Alcohol.MACROMOLECULAR MATERIALS AND ENGINEERING305(8)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeeksha B, Sadanand V, Rajulu NHariramAV (2021) Preparation and properties of cellulose nanocomposite fabrics with in situ generated silver nanoparticles by bioreduction method. J Bioresources Bioprod 6(1):75\u0026ndash;81\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAshok B, Hariram N, Rajulu SSiengchinAV (2020) Modification of tamarind fruit shell powder with in situ generated copper nanoparticles by single step hydrothermal method. J Bioresources Bioprod 5(3):180\u0026ndash;185\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu X, Souzandeh H, Zheng Y, Xie Y, ZhongC W-H, Wang (2017) Soy protein isolate/bacterial cellulose composite membranes for high efficiency particulate air filtration. Compos Sci Technol 138:124\u0026ndash;133\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTian HF, Fu XW, Zheng M, Wang Y, Li YC, XiangW AM, Zhong H (2018) Natural polypeptides treat pollution complex: Moisture-resistant multi-functional protein nanofabrics for sustainable air filtration. Nano Res 11(8):4265\u0026ndash;4277\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eY X WangL Y, Chen (2012) Electrospinning of Prolamin Proteins in Acetic Acid: The Effects of Protein Conformation and Aggregation in Solution. Macromol Mater Eng 297(9):902\u0026ndash;913\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark JH, Park SM, Kim YH, Oh W, Lee GW, Karim MR, ParkJ JH, Yeum H (2013) Effect of montmorillonite on wettability and microstructure properties of zein/montmorillonite nanocomposite nanofiber mats. J Compos Mater 47(2):251\u0026ndash;257\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYu X, Li CM, Tian HF, Yuan L, Xiang AM, Li JL, C Y WangA V Rajulu (2020) Hydrophobic cross-linked zein-based nanofibers with efficient air filtration and improved moisture stability.CHEMICAL ENGINEERING JOURNAL396\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChatzinasiou L, Booker A, MacLennan E, Heinrich MMackonochieM (2019) Turmeric (Curcuma longa L.) products: What quality differences exist?JOURNAL OF HERBAL MEDICINE17\u0026ndash;18\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStohs SJ, Ji J, BucciH LR, Preuss G (2018) A Comparative Pharmacokinetic Assessment of a Novel Highly Bioavailable Curcumin Formulation with 95% Curcumin: A Randomized, Double-Blind, Crossover Study. JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION 37(1):51\u0026ndash;59\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKharat M, Skrzynski M, DeckerD EA, McClements J (2020) Enhancement of chemical stability of curcumin-enriched oil-in-water emulsions: Impact of antioxidant type and concentration. FOOD CHEMISTRY 320\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhumsuay R, Muangnoi C, Wasana PWD, Hasriadi O, Vajragupta PRojsitthisakP, Towiwat (2020) Molecular Insight into the Anti-Inflammatory Effects of the Curcumin Ester Prodrug Curcumin Diglutaric Acid In Vitro and In Vivo.INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES21(16)\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoller K, Bein BMacaulayT (2021) Curcumin Encapsulated in Crosslinked Cyclodextrin Nanoparticles Enables Immediate Inhibition of Cell Growth and Efficient Killing of Cancer Cells. NANOMATERIALS 11(2):489\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J, Shin GH, Lee IW, ChenH X, Park J (2016) Soluble starch formulated nanocomposite increases water solubility and stability of curcumin. Food Hydrocolloids 56:41\u0026ndash;49\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRani P, Yu X, Liu HT, Li K, He Y, TianR Kumar HF (2021) Material, antibacterial and anticancer properties of natural polyphenols incorporated soy protein isolate: A review.EUROPEAN POLYMER JOURNAL152\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang YX, YangL JQ, Chen Y (2015) Convenient Fabrication of Electrospun Prolamin Protein Delivery System with Three-Dimensional Shapeability and Resistance to Fouling. ACS APPLIED MATERIALS \u0026amp; INTERFACES 7(24):13422\u0026ndash;13430\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMizutani Y, Matsumura Y, Imamura K, Mori KNakanishiT (2003) Effects of water activity and lipid addition on secondary structure of zein in powder systems. J Agric Food Chem 51(1):229\u0026ndash;235\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eF SecundoN Guerrieri (2005) ATR-FT/IR Study on the Interactions between Gliadins and Dextrin and Their Effects on Protein Secondary Structure. J Agric Food Chem 53(5):1757\u0026ndash;1764\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi P, Wang CY, ZhangF Wei YY (2014) Air Filtration in the Free Molecular Flow Regime: A Review of High-Efficiency Particulate Air Filters Based on Carbon Nanotubes. SMALL 10(22):4543\u0026ndash;4561\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen FP, LiC BS, Tang H (2015) Nanocomplexation between Curcumin and Soy Protein Isolate: Influence on Curcumin Stability/Bioaccessibility and in Vitro Protein Digestibility. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 63(13):3559\u0026ndash;3569\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCui JX, Li FH, Wang YL, Zhang QL (2020) W J MaC B Huang Electrospun nanofiber membranes for wastewater treatment applications. SEPARATION AND PURIFICATION TECHNOLOGY 250\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymers-and-the-environment","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jooe","sideBox":"Learn more about [Journal of Polymers and the Environment](https://www.springer.com/journal/10924)","snPcode":"10924","submissionUrl":"https://submission.nature.com/new-submission/10924/3","title":"Journal of Polymers and the Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Zein, Curcumin, Electrospinning, Hydrophobic, Air filtration","lastPublishedDoi":"10.21203/rs.3.rs-1812451/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1812451/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eZein as a natural protein had been widely used in various fields due to its biodegradability and biocompatibility. However, its sensitivity to humidity and poor mechanical performance limited its application in practice. In this study, zein-based composite nanofibers loaded with curcumin were prepared by electrospinning assisted with polyvinyl alcohol (PVA). The filtration efficiency of the modified nanofibers to the particles with diameters larger than 0.5 \u0026micro;m was all above 98%. The loaded curcumin interacted with protein molecular chains to form a network structure within tightly connected nanofibers, which exhibited excellent moisture resistance and good adhesion to cellulose paper towels used as air filter substrates. Meanwhile, its tensile strength had also been enhanced vastly to 0.72 MPa compared with the initial tensile strength of 0.21 MPa. This study provides a new electrospinning strategy for the preparation of zein-based composite nanofibers that can be widely utilized in air filtration with high moisture resistance.\u003c/p\u003e","manuscriptTitle":"Electrospun hydrophobic nanofiber films from biodegradable zein and curcumin with improved tensile strength for air filtration","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-07-07 16:57:23","doi":"10.21203/rs.3.rs-1812451/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2022-07-05T17:48:00+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-07-04T10:06:24+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-07-02T00:49:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Polymers and the Environment","date":"2022-06-30T11:32:40+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymers-and-the-environment","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jooe","sideBox":"Learn more about [Journal of Polymers and the Environment](https://www.springer.com/journal/10924)","snPcode":"10924","submissionUrl":"https://submission.nature.com/new-submission/10924/3","title":"Journal of Polymers and the Environment","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0f349b8a-0a49-49e0-add7-4659284082dd","owner":[],"postedDate":"July 7th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2022-08-18T13:22:54+00:00","versionOfRecord":[],"versionCreatedAt":"2022-07-07 16:57:23","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1812451","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1812451","identity":"rs-1812451","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}