Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection

Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection | 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 Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection Forough Vahedi, Nasser Arsalani, Mohammad Amjadi This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4459089/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Highly fluorescent non-conjugated polymer dots (PDs) were synthesized by an aqueous synthetic route using a hydrothermal method from polyester prepared with PEG and di-anhydride EDTA (DA-EDTA). The synthesized PDs display strong blue fluorescence with a high quantum yield (QY) of 45% in water and more than 45% in ethanol, dimethyl sulfoxide, N, N-dimethyl formamid, and acetone. The optical and structural properties of the PDs were investigated by UV–Vis, fluorescence spectrophotometry, EDX, FTIR, SEM, TEM, AFM, and DLS. The PDs were used as a sensitive fluorescence probe for Fe 3+ ions detection, with a low detection limit of 1.28 µM. The linear range in which fluorescent intensity decreases with increasing Fe 3+ is 0-120 µM. Besides, in the range of 20℃ to 70 ℃, fluorescent intensity declines with increasing temperature. Therefore, it can also be used as a thermometer. The spike recovery test confirmed the practicality of the method for the analysis of Fe 3+ ions in tap water samples. polymer dot temperature responsive Fe3+ detection polyester tap water Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Introduction Iron(Ⅲ) has important functions in the body, including cellular metabolism, enzymatic catalysis, DNA and RNA synthesis, and electron transport [ 1 , 2 ]. So, as expected, the defect or excess of this ion in the body will definitely cause diseases such as anemia and Parkinson’s syndrome [ 3 , 4 ]. Therefore, to prevent such diseases, significant levels must be maintained in the body. There are several methods for the quantitative detection of Fe 3+ , such as atomic absorption spectrometry [ 5 ], voltammetry [ 6 ] and colorimetric method [ 7 ]. These methods require expensive equipment and are not easy to implement. Recently, among these methods, relatively new fluorescent-based methods have received attention because of their advantages, such as high sensitivity and ease of use. Carbon dots (CDs) are nanomaterials with high photoluminescence properties and high solubility in water and are almost non-toxic [ 8 – 10 ]. Therefore, CDs are favorable agents for sensing various ions using fluorescent techniques [ 11 , 12 ]. Polymer dots (PDs) are a type of carbon dots that also have the performance of polymers [ 13 – 15 ]. Recently, non-conjugated linear polymers such as PEG, PEI, and PVA, unlike conjugated polymers, have received more attention because of the presence of easy dehydration groups [ 16 – 24 ]. PDs have features such as a single emission center, more stability, and high quantum yield (QY), which lead to their efficiency in fields such as sensing of metal ions, temperature, and pH. For example, Lai et al. prepared PDs from glucose and glycine by hydrothermal treatment, which can be used as a fluorescent probe to detect iron ions in aqueous solutions with suitable selectivity and sensitivity [ 25 ]. Zhang et al. prepared PDs with PEI and citric acid to detect Cu 2+ and ClO − with good sensitivity [ 26 ]. The next example is Xia et al. who synthesized PDs from ascorbic acid and diethylenetriamine, which were used to assay Fe 3+ with low LOD [ 27 ]. Wang et al. prepared PDs modified with glutathione, which can be used as a dual-functional sensor of Fe 3+ and temperature [ 21 ]. In general, PDs with high quantum yield and high sensitivity are desirable for Fe 3+ ion quantitative detection. Here, we report a hydrothermal method for the synthesis of non-conjugated PDs using water-soluble polyester based on PEG and di-anhydride EDTA (DA-EDTA or BA-EDTA). The as-synthesized PDs can be used for selective and sensitive detection of Fe 3+ as well as for temperature sensing. The LOD of this method is within the acceptable limit (1.28 µM) and the linear range of detection is 0-120 µM, which indicates that it can be used for the quantitative measurement of Fe 3+ in drinking water. To evaluate the practicality of this method, PDs were also tested in tap water and successfully confirmed. Experimental 2.1. Materials FeCl 3 .6H 2 O, 99%, EDTA, PEG (M W =2000), acetic anhydride, pyridine, toluene, ethanol, N, N-dimethyl formamide, acetone, dimethyl sulfoxide, diethyl ether, tetrahydrofuran, KCl, MgSO 4 , CuCl, CaCl 2 , CoCl 2 , CuSO 4 , MnCl 2 , Ni (NO 3 ) 2 , NaOH, NaCl, and ZnCl2 were obtained from Merck (Germany). 2.2. Characterization A Bruker Optics TENSOR 27 spectrometer was used to obtain the FT-IR spectra. Field emission scanning electron microscopy (MIRA3 Tescan, Czech Republic, FE-SEM) and TEM Philips EM 208S were used to investigate the morphology and mean size of the PDs. UV–vis spectra of the PDs were recorded using a Shimadzu UV-256 F.W spectrophotometer. All fluorescence spectra were measured using a FP-8300 spectrofluorimeter (Josco, Japan). Energy-dispersive X-ray (EDX) spectroscopy of the samples was performed using a Zeiss Sigma 300. Dynamic light scattering (DLS) measurements and the zeta potential of the PDs were performed using Microtrac’s Nanotrac Wave. An atomic force microscope (AFM, Swiss) was employed for morphological investigation and 3D imaging. 2.3. EDTA Dianhydride Synthesis (DA-EDTA) In a flask, EDTA (5.00 g, 17 mmol), acetic anhydride (7 mL), and pyridine (8 mL) were poured, and the reaction mixture was vigorously stirred at 70°C for 12 hours. The solid product (anhydride) was filtered off and washed thoroughly with dry diethyl ether and acetic anhydride. Then, it was dried under vacuum at 40°C. EDTA dianhydride was obtained as a pea-colored powder (yield 90%) [ 28 ]. 2.4. Preparation of the Polyester During 15 minutes, 0.256 g (1 mmol) of DA-EDTA powder was very slowly added into the molten PEG 2000 (2.0 g, 1 mmol) at 85°C and stirred under inert gas for 12 hours. Polyester was obtained in a soft solid state-(yield 63%). 2.5. Synthesis of the PDs The polyester obtained from the previous step was dissolved in distilled water and centrifuged, and the supernatant solution containing polyester was autoclaved at 180°C for 12 hours. PDs were obtained as a brown solution. They were centrifuged, and the supernatant was freeze-dried and stored in a dark and cool place. 2.6. Detection of Fe 3+ 50 mL of pure water was used to dissolve 50 mg of freeze-dried PDs, which were then sonicated for 20 minutes. Then, 2 mL of Fe 3+ solution with different concentrations was added to 2 mL of PD solution. The final concentrations of Fe 3+ in the mixed dispersions were 2, 10, 20, 30, 40, 50, 60, 70, 100, 120, 150, 300, 600, 1000 and 1500 µM. After approximately 10 minutes of sonication, the fluorescence intensity of the solutions was measured. Results and discussion 3.1. Characterization of the PDs To investigate the characteristics of the PDs, TEM, SEM, EDX, UV-Vis, fluorescence, DLS, and AFM were used to characterize them. TEM, AFM, and SEM analyses were performed to study the morphology and size of the PDs. As seen in Fig. 1 a, the PDs are hemispherical in shape and tend to aggregate. The TEM image of the PDs (Fig. 1 a) shows that the average particle size is approximately 34 nm, which is confirmed by both SEM (Fig. 1 c) and AFM (Fig. 1 b) images. In addition, DLS analysis was used to provide sufficient evidence for the polymer particle size, and this analysis showed (Fig. 1 d) that the average particle size was 44.3 nm, which is certainly larger than the size detected in SEM, TEM, and AFM images because DLS analysis shows the hydrodynamic radius. Zeta potential measurement confirmed that PDs have a negative charge of -27.0 mV, which indicates the presence of negatively charged functional groups on the surface of PDs and their hydrophilic nature, which makes them highly soluble in water. FTIR analysis was performed for BA-EDTA, polyester, and PDs (Fig. 2 a). The main peaks of BA-EDTA are clearly visible at 1762 and 1810 cm − 1 which are related to C = O stretching vibrations. In the spectrum related to polyester, as expected, the dianhydride peaks disappear and the polyester peaks in the regions of 3442, 1741, 1350 and 1105 cm − 1 correspond to the O-H, C = O, C-N and C-O groups, respectively. In the PDs spectrum a broadband at 3427 cm − 1 is related to the O-H group. Also, the sharp peaks located in the areas of 1346 and 1112 cm − 1 are related to C-N and C-O bands, respectively. The high solubility of PDs in water is most likely due to the existence of these polar functional groups on the surface of PDs. The elemental composition of the PDs in the EDX spectrum can be seen in Fig. 2 b, and the distribution of carbon, nitrogen, and oxygen is shown on the maps (Fig. 2 c-f). The atomic and weight percentages of carbon (C), nitrogen (N), and oxygen (O)are 65.74, 1.60 ,32.67 and 59.16, 1.68, and 39.16, respectively. 3.2. Optical properties of the PD The color of the PDs is light brown under ambient light and changes to blue under UV light. Two peaks were observed in the UV–vis absorption spectrum of the PDs at approximately 250 and 350 nm (Fig. 3 a). These peaks are probably related to the n–σ* transition of -NH2 and the n–π* transition of C = O [ 29 , 30 ]. The QY of PDs was found to be approximately 45% with reference to quinine sulfate. As shown in Fig. 3 b, unlike most carbon dots, the fluorescence emission of the prepared PDs does not depend on the excitation wavelength. At 414 and 330 nm, the optimum emission and excitation wavelengths were found. Another factor that was investigated, was pH. The influence of pH on the fluorescence intensity of the PDs was studied at room temperature for a range from pH = 2 to 13 (Fig. 4 ). The pH of the PDs solution affects its fluorescence intensity so that the pH values of 4 and 13 showed the highest and lowest fluorescence intensities, respectively. In general, the fluorescence intensity is higher in an acidic environment than in an alkaline solution, and in highly alkaline environments, the fluorescence intensity is greatly reduced. This property of PDs is due to the protonation of amino groups with a decrease in pH on their surfaces [ 29 ]. By making the environment more acidic (pH < 3), the fluorescence intensity decreases. The reason for this phenomenon is that excess acid has started to damage the dispersion of protonated PDs [ 30 ]. It was also investigated how the solvent affected the PDs’ fluorescence (Fig. 5 ). Although the PDs are efficiently dispersed in aqueous solutions, their polymeric structure and abundance of hydrophilic groups allow them to disperse in a variety of solvents. PDs in water, ethanol, dimethyl sulfoxide, N, N-dimethyl formamide, tetrahydrofuran, acetone, and toluene are associated with the emission peaks located at 414, 412.5, 411.5, 411, 410, and 407.5 nm, respectively. Generally speaking, as the polarity of the solvent increases, the emission wavelength redshifts because the PDs dispersed in different solvents possess both different refractive indexes and different dielectric constants [ 25 , 31 – 35 ]. Moreover, the QYs of PDs dispersed in ethanol, dimethyl sulfoxide, N, N-dimethyl formamide, and acetone are more than the QY of PDs in water, and the highest QY belongs to PDs in dimethyl sulfoxide. Because PDs do not disperse well in toluene solvent, the quantum yield of PDs in this solvent is very low (Fig. 5 ). 3.3. Thermo-responsive properties of the PDs The effect of temperature on the PL intensity of the PDs is also examined. In Fig. 6 a, it can be observed that when the solution temperature increases from 20 to 70°C, the PL intensity gradually decreases. Interestingly, a linear relationship between fluorescence intensity and temperature is achieved with a correlation coefficient of 0.9965 (Fig. 6 b). 3.4. Selective detection of Fe + 3 According to previous studies, Fe 3+ ion has a strong affinity for functional groups containing nitrogen and oxygen [ 25 , 27 , 36 ]. As a result, the interaction of Fe 3+ ions with prepared PDs containing nitrogen and oxygen functional groups changes the fluorescence intensity of PDs. In other words, Fe 3+ ion can quench the PL of PDs. The relationship between the degree of quenching and Fe 3+ concentration was investigated. As illustrated in Fig. 7 a, with increasing Fe 3+ concentration, the fluorescence intensity decreased, and by fitting the PL (F/F 0 ) ratio versus the Fe 3+ concentration in the range of 0 to 120 µM, a significant linear correlation with R² =0.9943 was obtained (Fig. 7 b). The limit of detection calculated by the 3σ/k is 1.28 µM. In this formula, "σ" represents the standard deviation of blank and "k" represents the slope of the linear region [ 37 – 39 ]. In the table below, different carbon dots or polymer dots, which were prepared from different sources, are compared in terms of quantum yield, detection limit, and linear range of response to Fe 3+ with synthetic polymer dots. As can be seen, the quantum yield of PDs is high and favorable in terms of low detection limit and wide linear range. Table 1 Comparison of the salient features of PDs prepared in this work with other CDs or PDs prepared for the detection of Fe 3+ ions Row materials QY Linear range (µM) LOD (µM) Reference 2,5-DABS and 4-aminophenylboronic acid hydrochloride 5.44% 0.3 _ 546 0.3 [ 40 ] Dopamine and ethanediamine 9.4% 50 _ 300 10.8 [ 41 ] Cranberry beans 10.85% 30 _ 600 9.55 [ 42 ] glutamic acid and ethylenediamine 12.45% 8 _ 80 3.8 [ 43 ] Prunus avium fruit extract 13% 0 _ 100 0.96 [ 44 ] polyethyleneimine and 5-aminosalicylic acid 15.5% 2 _ 60 0.36 [ 45 ] Thiourea and citric acid 23% 0.3 _ 5 0.1 [ 36 ] Snake gourd peel extract 28.6% 10 _ 100 0.398 [ 46 ] Citric acid and ethylenediamine 40.87% 0 _ 1200 1.68 [ 47 ] Peg 2000 and A-EDTA 45% 0 _ 120 1.28 This work An interesting point is that the rate of quenching of polymers by iron is very high; therefore, after 1 min of interaction, no noticeable difference in the rate of quenching of polymers is observed. (Fig. 8 ). So, the detection process of Fe 3+ can be ended within a few minutes. To study the selectivity of PDs, different ions were tested instead of Fe 3+ under completely similar conditions. As shown in Fig. 9 , none of the ions significantly reduced the fluorescence intensity of the PDs. Only Fe 3+ ions successfully quenched the PL intensity of the PDs. The reliability of this assay was confirmed by the quantitative detection of Fe 3+ in local tap water. We prepared three spiked samples with diverse quantities of Fe 3+ . As shown in Table 2 , the outcomes were very satisfactory, and the recoveries ranged from 94.05 to 106.4%, which proves the practicality and applicability of the assay. Table 2 Measurement of Fe 3+ ions in tap water samples Samples Spiked (µM) Found (µM) Recovery (%) 1 30 28.76 95 2 60 56.43 94.05 3 90 95.76 106.4 Conclusions In summary, the brown fluorescent polymer dots with excitation-independent emission, high quantum yield (45%), and excellent water dispersibility were synthesized by a simple hydrothermal process. The prepared PDs were applied as a fluorescence probe that can selectively and quantitatively detect Fe 3+ ions with high sensitivity in the range of 0-120 µM with the appropriate LOD of 1.28 µM. In addition, the PDs display good temperature response performance in the range of 20–70°C. Therefore, the fluorescent PDs can be applied for precise quantitative measurement of both temperature and Fe 3+ ions. Declarations Acknowledgments The authors gratefully acknowledge the University of Tabriz. Author contributions Not Applicable Conflicts of interest or 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. Data and code availability Not Applicable Supplementary information Not Applicable Ethical approval Not Applicable References Tuelue M, Geckeler KE. Synthesis and properties of hydrophilic polymers. Part 7. Preparation, characterization and metal complexation of carboxy‐functional polyesters based on poly (ethylene glycol). Polymer international, 1999. 48 (9): p. 909-914. Hentze, M.W., et al., Two to tango: regulation of Mammalian iron metabolism. Cell, 2010. 142 (1): p. 24-38. Qin, C., et al., Surface catalyzed oxidative oligomerization of 17β-estradiol by Fe3+-saturated montmorillonite. Environmental science & technology, 2015. 49 (2): p. 956-964. Altamura, S. and M.U. Muckenthaler, Iron toxicity in diseases of aging: Alzheimer's disease, Parkinson's disease and atherosclerosis. Journal of Alzheimer's Disease, 2009. 16 (4): p. 879-895. Wang, R., et al., A turn-on fluorescent probe based on hydroxylamine oxidation for detecting ferric ion selectively in living cells. Chemical Communications, 2012. 48 (43): p. 5310-5312. Bobrowski, A., K. Nowak, and J. Zarębski, Application of a bismuth film electrode to the voltammetric determination of trace iron using a Fe (III)–TEA–BrO 3− catalytic system. Analytical and bioanalytical chemistry, 2005. 382 : p. 1691-1697. Liu, B., J. Zhuang, and G. Wei, Recent advances in the design of colorimetric sensors for environmental monitoring. Environmental Science: Nano, 2020. 7 (8): p. 2195-2213. Shen, P., et al., Synthesis of cellulose‐based carbon dots for bioimaging. ChemistrySelect, 2016. 1 (7): p. 1314-1317. Lu, W., et al., Economical, green synthesis of fluorescent carbon nanoparticles and their use as probes for sensitive and selective detection of mercury (II) ions. Analytical chemistry, 2012. 84 (12): p. 5351-5357. da Silva Souza, D.R., et al., Luminescent carbon dots obtained from cellulose. Materials Chemistry and Physics, 2018. 203 : p. 148-155. Demir, B., et al., Tracking hyaluronan: molecularly imprinted polymer coated carbon dots for cancer cell targeting and imaging. ACS applied materials & interfaces, 2018. 10 (4): p. 3305-3313. Bai, Z., et al., Dual-channel fluorescence detection of mercuric (II) and glutathione by down-and up-conversion fluorescence carbon dots. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018. 205 : p. 29-39. Zhu, S., et al., The photoluminescence mechanism in carbon dots (graphene quantum dots, carbon nanodots, and polymer dots): current state and future perspective. Nano research, 2015. 8 : p. 355-381. Xia, C., et al., Evolution and synthesis of carbon dots: from carbon dots to carbonized polymer dots. Advanced Science, 2019. 6 (23): p. 1901316. Sheng, Y., et al., A label-free ratiometric fluorescence nanoprobe for ascorbic acid based on redox-modulated dual-emission signals. Analyst, 2019. 144 (11): p. 3511-3517. Zhu, S., et al., Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging. Angewandte Chemie International Edition, 2013. 52 (14): p. 3953-3957. Tao, S., et al., The polymeric characteristics and photoluminescence mechanism in polymer carbon dots: A review. Materials today chemistry, 2017. 6 : p. 13-25. Song, Y., et al., Investigation into the fluorescence quenching behaviors and applications of carbon dots. Nanoscale, 2014. 6 (9): p. 4676-4682. Jaiswal, A., S.S. Ghosh, and A. Chattopadhyay, One step synthesis of C-dots by microwave mediated caramelization of poly (ethylene glycol). Chemical communications, 2012. 48 (3): p. 407-409. Fan, R.-J., et al., Photoluminescent carbon dots directly derived from polyethylene glycol and their application for cellular imaging. Carbon, 2014. 71 : p. 87-93. Wang, C., et al., Bi-functional fluorescent polymer dots: a one-step synthesis via controlled hydrothermal treatment and application as probes for the detection of temperature and Fe 3+. Journal of Materials Chemistry C, 2017. 5 (2): p. 434-443. Li, H., et al., One-step ultrasonic synthesis of water-soluble carbon nanoparticles with excellent photoluminescent properties. Carbon, 2011. 49 (2): p. 605-609. Wang, C., et al., A hydrothermal route to water-stable luminescent carbon dots as nanosensors for pH and temperature. Carbon, 2015. 82 : p. 87-95. Zhu, S., et al., The crosslink enhanced emission (CEE) in non-conjugated polymer dots: from the photoluminescence mechanism to the cellular uptake mechanism and internalization. Chemical communications, 2014. 50 (89): p. 13845-13848. Lai, T., et al., Hybrid carbon source for producing nitrogen-doped polymer nanodots: one-pot hydrothermal synthesis, fluorescence enhancement and highly selective detection of Fe (III). Nanoscale, 2013. 5 (17): p. 8015-8021. Zhang, H., et al., Fluorescence emission of polyethylenimine-derived polymer dots and its application to detect copper and hypochlorite ions. ACS applied materials & interfaces, 2019. 11 (35): p. 32489-32499. Xia, J., et al., Highly fluorescent carbon polymer dots prepared at room temperature, and their application as a fluorescent probe for determination and intracellular imaging of ferric ion. Microchimica Acta, 2017. 184 : p. 1109-1116. Arsalani, N. and S.Z. Mousavi, Synthesis and characterization of water-soluble and carboxy-functional polyester and polyamide based on ethylenediamine-tetraacetic acid and their metal complexes. 2003. Dong, Y., et al., Polyamine-functionalized carbon quantum dots for chemical sensing. Carbon, 2012. 50 (8): p. 2810-2815. Liu, Y., et al., One-step synthesis of robust nitrogen-doped carbon dots: acid-evoked fluorescence enhancement and their application in Fe 3+ detection. Journal of Materials Chemistry A, 2015. 3 (34): p. 17747-17754. Moniruzzaman, M. and J. Kim, N-doped carbon dots with tunable emission for multifaceted application: solvatochromism, moisture sensing, pH sensing, and solid state multicolor lighting. Sensors and Actuators B: Chemical, 2019. 295 : p. 12-21. Reckmeier, C.J., et al., Influence of doping and temperature on solvatochromic shifts in optical spectra of carbon dots. The Journal of Physical Chemistry C, 2016. 120 (19): p. 10591-10604. Ling, Y., et al., Enhanced emission of polyethyleneimine-coated copper nanoclusters and their solvent effect. The Journal of Physical Chemistry C, 2015. 119 (48): p. 27173-27177. Mukherjee, S., E. Prasad, and A. Chadha, H-Bonding controls the emission properties of functionalized carbon nano-dots. Physical Chemistry Chemical Physics, 2017. 19 (10): p. 7288-7296. Lu, S., et al., Near‐infrared photoluminescent polymer–carbon nanodots with two‐photon fluorescence. Advanced materials, 2017. 29 (15): p. 1603443. Li, C., et al., Red fluorescent carbon dots with phenylboronic acid tags for quick detection of Fe (III) in PC12 cells. Journal of colloid and interface science, 2018. 526 : p. 487-496. Ji, C., et al., Facile and sensitive detection of nitrogen-containing organic bases with near infrared C-dots derived assays. Nanomaterials, 2021. 11 (10): p. 2607. Mintz, K., et al., Carbon dots and gold nanoparticle’s based immunoassay for detection of alpha-L-fucosidase. Analytica chimica acta, 2018. 1041 : p. 114-121. Forootan, A., et al., Methods to determine limit of detection and limit of quantification in quantitative real-time PCR (qPCR). Biomolecular detection and quantification, 2017. 12 : p. 1-6. Liu, Y., et al., Red emission B, N, S-co-doped carbon dots for colorimetric and fluorescent dual mode detection of Fe3+ ions in complex biological fluids and living cells. ACS applied materials & interfaces, 2017. 9 (14): p. 12663-12672. Li, G., et al., Nitrogen-doped carbon dots as a fluorescence probe suitable for sensing Fe 3+ under acidic conditions. New Journal of Chemistry, 2016. 40 (12): p. 10213-10218. Zulfajri, M., et al., Cranberry beans derived carbon dots as a potential fluorescence sensor for selective detection of Fe3+ ions in aqueous solution. ACS omega, 2019. 4 (13): p. 15382-15392. Chen, Y., et al., Fe3+-sensitive carbon dots for detection of Fe3+ in aqueous solution and intracellular imaging of Fe3+ inside fungal cells. Frontiers in Chemistry, 2020. 7 : p. 911. Edison, T.N.J.I., et al., Turn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging. Journal of Photochemistry and Photobiology B: Biology, 2016. 158 : p. 235-242. Tang, Y., et al., One-pot synthesis of fluorescent non-conjugated polymer dots for Fe3+ detection and temperature sensing. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020. 240 : p. 118626. Sailaja Prasannakumaran Nair, S., N. Kottam, and P.K. SG, Green synthesized luminescent carbon nanodots for the sensing application of Fe 3+ ions. Journal of Fluorescence, 2020. 30 : p. 357-363. Xiang, Z., et al., Sensitive, Selective and Reliable Detection of Fe3+ in Lake Water via Carbon Dots-Based Fluorescence Assay. Molecules, 2022. 27 (19): p. 6749. Additional Declarations No competing interests reported. Supplementary Files floatimage1.jpeg Graphical Abstract Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4459089","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":308538106,"identity":"fd9f6c8e-9820-48c6-95bc-7212b339217c","order_by":0,"name":"Forough Vahedi","email":"","orcid":"","institution":"University of Tabriz","correspondingAuthor":false,"prefix":"","firstName":"Forough","middleName":"","lastName":"Vahedi","suffix":""},{"id":308538107,"identity":"efa9ac09-189b-477b-9099-aab24ae0d9aa","order_by":1,"name":"Nasser Arsalani","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA60lEQVRIie3RsYoCMRCA4amyzUDaCHr3CrMsrHa+SoJw1RbXaSESELbUB/A9rCwWAmsTrC0OziBsZWElFsdhFuzEVTuL/OWQjxkIQCj0ru0AkAMwALpO5CPiH2Arf5UAlTV5Jr5Yu6Mc/7ST32m1H31PlI7MDtzqPhGbLBGyrDAtWTe2xJTGLwJZNayxCEIy4wmkLU2oNGT+1OK++LTR/iz/DSZ5dPJEKM0PzYQspELlBolhvYWUFg+2xBbTnpoZFGU2jDXJJBcVFU3kwx+2PZ5Mn0/XS6f/Jp05Hzh3biC31b/zEgiFQqHQbRfxh01xKz40nAAAAABJRU5ErkJggg==","orcid":"","institution":"University of Tabriz","correspondingAuthor":true,"prefix":"","firstName":"Nasser","middleName":"","lastName":"Arsalani","suffix":""},{"id":308538108,"identity":"71b78d30-b9f6-4d0b-a271-714115c78a0d","order_by":2,"name":"Mohammad Amjadi","email":"","orcid":"","institution":"University of Tabriz","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"","lastName":"Amjadi","suffix":""}],"badges":[],"createdAt":"2024-05-22 07:50:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4459089/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4459089/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":57792153,"identity":"6cb68dd4-eeb5-4ed9-817f-351745562935","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":816982,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) TEM image (150 nm scale) and histogram plot \u003cstrong\u003eb\u003c/strong\u003e) AFM image (5 μm scale) and 3D view of the AFM image (the same scale) \u003cstrong\u003ec\u003c/strong\u003e) SEM image (200 nm scale) \u003cstrong\u003ed\u003c/strong\u003e) DLS analysis\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/93c78e7ded967b8d343f24d8.png"},{"id":57792377,"identity":"1d6898f3-4fd0-462a-9565-69562946c28e","added_by":"auto","created_at":"2024-06-05 18:00:19","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":398883,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) FTIR spectra of DA-EDTA, polyester, and PDs; \u003cstrong\u003eb\u003c/strong\u003e) EDX micrograph of PDs and elemental mapping of PDs; \u003cstrong\u003ec\u003c/strong\u003e) carbon; \u003cstrong\u003ed\u003c/strong\u003e) nitrogen; \u003cstrong\u003ee\u003c/strong\u003e) oxygen; and \u003cstrong\u003ef\u003c/strong\u003e) total\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/6efbd28ef49cf7d2ff52230f.png"},{"id":57792154,"identity":"38b5d1a7-0c42-41ff-8186-6e07ad50ff3f","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":155240,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) UV– vis spectra of PDs, \u003cstrong\u003eb\u003c/strong\u003e) the emission intensities of PDs at different excitations\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/3476bd16bd6f0291da5a6dcb.png"},{"id":57792155,"identity":"de3b72b4-100e-418a-8c6d-5dd107ed2ba8","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":198234,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) Fluorescence intensity of PDs in acidic, basic and neutral environments, \u003cstrong\u003eb\u003c/strong\u003e) Effect of pH on the PL intensity of PDs\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/ed8779b1a4267816ccc03dcf.png"},{"id":57792157,"identity":"02619ea3-e3bc-400c-8c1c-4ed7ab0136d9","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":122988,"visible":true,"origin":"","legend":"\u003cp\u003eSolvent effect on the PL intensity of the PDs\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/84ab862fde5c6c6b2cf66eca.png"},{"id":57792158,"identity":"db471139-31a5-406c-8f88-104fc0fef388","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":175016,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) Fluorescence intensity of PDs at different temperatures (20℃ - 70℃), \u003cstrong\u003eb\u003c/strong\u003e) Linear relationship between PL intensity and temperature (20℃ - 70℃)\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/3d29d8586e71940ce127751f.png"},{"id":57792160,"identity":"47fd353c-5aa0-4fc8-8564-4f1c6959b762","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":208862,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) Fluorescence spectra of the PDs in different concentrations of Fe\u003csup\u003e3+\u003c/sup\u003e ions (2-1500 μM), \u003cstrong\u003eb\u003c/strong\u003e) Linear relationship graph (0-120 μM)\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/39800c08b4d08102073e93e7.png"},{"id":57792163,"identity":"7a8b5252-a11e-48bd-8c8e-44f542141ccc","added_by":"auto","created_at":"2024-06-05 17:52:20","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":59949,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) Fluorescence spectra of the PDs after adding a certain amount of Fe\u003csup\u003e3+\u003c/sup\u003e ions over time, \u003cstrong\u003eb\u003c/strong\u003e) quenching rate of PDs by Fe\u003csup\u003e3+\u003c/sup\u003e ions\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/5824577fb97b0d439498c0a3.png"},{"id":57792162,"identity":"e7962e67-89ed-4b76-b8cf-33a27c19b82e","added_by":"auto","created_at":"2024-06-05 17:52:19","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":65798,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ea\u003c/strong\u003e) Fluorescence spectra of the PDs upon addition of some substances \u003cstrong\u003eb\u003c/strong\u003e) Selectivity of PDs to Fe\u003csup\u003e3+\u003c/sup\u003e (Fe\u003csup\u003e3+\u003c/sup\u003e = 60 μM and other ions = 200 μM)\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/fa23ec2df1ae171314229886.png"},{"id":58963766,"identity":"fc159aac-5040-4ee6-9805-2b10fa72fd65","added_by":"auto","created_at":"2024-06-24 17:29:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2769238,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/b382f5d2-c996-45ae-b5f9-d4c5847513b6.pdf"},{"id":57792376,"identity":"1ea89ed1-6f9e-47e8-afc0-944bc919131d","added_by":"auto","created_at":"2024-06-05 18:00:19","extension":"jpeg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":153092,"visible":true,"origin":"","legend":"\u003cp\u003eGraphical Abstract\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4459089/v1/6848cd4dc24eef0dfaf7e360.jpeg"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIron(Ⅲ) has important functions in the body, including cellular metabolism, enzymatic catalysis, DNA and RNA synthesis, and electron transport [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. So, as expected, the defect or excess of this ion in the body will definitely cause diseases such as anemia and Parkinson\u0026rsquo;s syndrome [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Therefore, to prevent such diseases, significant levels must be maintained in the body. There are several methods for the quantitative detection of Fe\u003csup\u003e3+\u003c/sup\u003e, such as atomic absorption spectrometry [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], voltammetry [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] and colorimetric method [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. These methods require expensive equipment and are not easy to implement. Recently, among these methods, relatively new fluorescent-based methods have received attention because of their advantages, such as high sensitivity and ease of use. Carbon dots (CDs) are nanomaterials with high photoluminescence properties and high solubility in water and are almost non-toxic [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Therefore, CDs are favorable agents for sensing various ions using fluorescent techniques [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Polymer dots (PDs) are a type of carbon dots that also have the performance of polymers [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Recently, non-conjugated linear polymers such as PEG, PEI, and PVA, unlike conjugated polymers, have received more attention because of the presence of easy dehydration groups [\u003cspan additionalcitationids=\"CR17 CR18 CR19 CR20 CR21 CR22 CR23\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. PDs have features such as a single emission center, more stability, and high quantum yield (QY), which lead to their efficiency in fields such as sensing of metal ions, temperature, and pH. For example, Lai et al. prepared PDs from glucose and glycine by hydrothermal treatment, which can be used as a fluorescent probe to detect iron ions in aqueous solutions with suitable selectivity and sensitivity [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. Zhang et al. prepared PDs with PEI and citric acid to detect Cu\u003csup\u003e2+\u003c/sup\u003e and ClO\u003csup\u003e\u0026minus;\u003c/sup\u003e with good sensitivity [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The next example is Xia et al. who synthesized PDs from ascorbic acid and diethylenetriamine, which were used to assay Fe\u003csup\u003e3+\u003c/sup\u003e with low LOD [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Wang et al. prepared PDs modified with glutathione, which can be used as a dual-functional sensor of Fe\u003csup\u003e3+\u003c/sup\u003e and temperature [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In general, PDs with high quantum yield and high sensitivity are desirable for Fe\u003csup\u003e3+\u003c/sup\u003e ion quantitative detection.\u003c/p\u003e \u003cp\u003eHere, we report a hydrothermal method for the synthesis of non-conjugated PDs using water-soluble polyester based on PEG and di-anhydride EDTA (DA-EDTA or BA-EDTA). The as-synthesized PDs can be used for selective and sensitive detection of Fe\u003csup\u003e3+\u003c/sup\u003e as well as for temperature sensing. The LOD of this method is within the acceptable limit (1.28 \u0026micro;M) and the linear range of detection is 0-120 \u0026micro;M, which indicates that it can be used for the quantitative measurement of Fe\u003csup\u003e3+\u003c/sup\u003e in drinking water. To evaluate the practicality of this method, PDs were also tested in tap water and successfully confirmed.\u003c/p\u003e"},{"header":"Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1. Materials\u003c/h2\u003e \u003cp\u003eFeCl\u003csub\u003e3\u003c/sub\u003e.6H\u003csub\u003e2\u003c/sub\u003eO, 99%, EDTA, PEG (M\u003csub\u003eW\u003c/sub\u003e=2000), acetic anhydride, pyridine, toluene, ethanol, N, N-dimethyl formamide, acetone, dimethyl sulfoxide, diethyl ether, tetrahydrofuran, KCl, MgSO\u003csub\u003e4\u003c/sub\u003e, CuCl, CaCl\u003csub\u003e2\u003c/sub\u003e, CoCl\u003csub\u003e2\u003c/sub\u003e, CuSO\u003csub\u003e4\u003c/sub\u003e, MnCl\u003csub\u003e2\u003c/sub\u003e, Ni (NO\u003csub\u003e3\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e, NaOH, NaCl, and ZnCl2 were obtained from Merck (Germany).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2. Characterization\u003c/h2\u003e \u003cp\u003eA Bruker Optics TENSOR 27 spectrometer was used to obtain the FT-IR spectra. Field emission scanning electron microscopy (MIRA3 Tescan, Czech Republic, FE-SEM) and TEM Philips EM 208S were used to investigate the morphology and mean size of the PDs. UV\u0026ndash;vis spectra of the PDs were recorded using a Shimadzu UV-256 F.W spectrophotometer. All fluorescence spectra were measured using a FP-8300 spectrofluorimeter (Josco, Japan). Energy-dispersive X-ray (EDX) spectroscopy of the samples was performed using a Zeiss Sigma 300. Dynamic light scattering (DLS) measurements and the zeta potential of the PDs were performed using Microtrac\u0026rsquo;s Nanotrac Wave. An atomic force microscope (AFM, Swiss) was employed for morphological investigation and 3D imaging.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3. EDTA Dianhydride Synthesis (DA-EDTA)\u003c/h2\u003e \u003cp\u003eIn a flask, EDTA (5.00 g, 17 mmol), acetic anhydride (7 mL), and pyridine (8 mL) were poured, and the reaction mixture was vigorously stirred at 70\u0026deg;C for 12 hours. The solid product (anhydride) was filtered off and washed thoroughly with dry diethyl ether and acetic anhydride. Then, it was dried under vacuum at 40\u0026deg;C. EDTA dianhydride was obtained as a pea-colored powder (yield 90%) [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4. Preparation of the Polyester\u003c/h2\u003e \u003cp\u003eDuring 15 minutes, 0.256 g (1 mmol) of DA-EDTA powder was very slowly added into the molten PEG 2000 (2.0 g, 1 mmol) at 85\u0026deg;C and stirred under inert gas for 12 hours. Polyester was obtained in a soft solid state-(yield 63%).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.5. Synthesis of the PDs\u003c/h2\u003e \u003cp\u003eThe polyester obtained from the previous step was dissolved in distilled water and centrifuged, and the supernatant solution containing polyester was autoclaved at 180\u0026deg;C for 12 hours. PDs were obtained as a brown solution. They were centrifuged, and the supernatant was freeze-dried and stored in a dark and cool place.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.6. Detection of Fe\u003csup\u003e3+\u003c/sup\u003e\u003c/h2\u003e \u003cp\u003e50 mL of pure water was used to dissolve 50 mg of freeze-dried PDs, which were then sonicated for 20 minutes. Then, 2 mL of Fe\u003csup\u003e3+\u003c/sup\u003e solution with different concentrations was added to 2 mL of PD solution. The final concentrations of Fe\u003csup\u003e3+\u003c/sup\u003e in the mixed dispersions were 2, 10, 20, 30, 40, 50, 60, 70, 100, 120, 150, 300, 600, 1000 and 1500 \u0026micro;M. After approximately 10 minutes of sonication, the fluorescence intensity of the solutions was measured.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results and discussion","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Characterization of the PDs\u003c/h2\u003e \u003cp\u003eTo investigate the characteristics of the PDs, TEM, SEM, EDX, UV-Vis, fluorescence, DLS, and AFM were used to characterize them. TEM, AFM, and SEM analyses were performed to study the morphology and size of the PDs. As seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea, the PDs are hemispherical in shape and tend to aggregate. The TEM image of the PDs (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea) shows that the average particle size is approximately 34 nm, which is confirmed by both SEM (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec) and AFM (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb) images. In addition, DLS analysis was used to provide sufficient evidence for the polymer particle size, and this analysis showed (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed) that the average particle size was 44.3 nm, which is certainly larger than the size detected in SEM, TEM, and AFM images because DLS analysis shows the hydrodynamic radius.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eZeta potential measurement confirmed that PDs have a negative charge of -27.0 mV, which indicates the presence of negatively charged functional groups on the surface of PDs and their hydrophilic nature, which makes them highly soluble in water. FTIR analysis was performed for BA-EDTA, polyester, and PDs (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). The main peaks of BA-EDTA are clearly visible at 1762 and 1810 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e which are related to C\u0026thinsp;=\u0026thinsp;O stretching vibrations. In the spectrum related to polyester, as expected, the dianhydride peaks disappear and the polyester peaks in the regions of 3442, 1741, 1350 and 1105 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e correspond to the O-H, C\u0026thinsp;=\u0026thinsp;O, C-N and C-O groups, respectively. In the PDs spectrum a broadband at 3427 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e is related to the O-H group. Also, the sharp peaks located in the areas of 1346 and 1112 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e are related to C-N and C-O bands, respectively. The high solubility of PDs in water is most likely due to the existence of these polar functional groups on the surface of PDs. The elemental composition of the PDs in the EDX spectrum can be seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, and the distribution of carbon, nitrogen, and oxygen is shown on the maps (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec-f). The atomic and weight percentages of carbon (C), nitrogen (N), and oxygen (O)are 65.74, 1.60 ,32.67 and 59.16, 1.68, and 39.16, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Optical properties of the PD\u003c/h2\u003e \u003cp\u003eThe color of the PDs is light brown under ambient light and changes to blue under UV light. Two peaks were observed in the UV\u0026ndash;vis absorption spectrum of the PDs at approximately 250 and 350 nm (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea). These peaks are probably related to the n\u0026ndash;σ* transition of -NH2 and the n\u0026ndash;π* transition of C\u0026thinsp;=\u0026thinsp;O [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The QY of PDs was found to be approximately 45% with reference to quinine sulfate. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb, unlike most carbon dots, the fluorescence emission of the prepared PDs does not depend on the excitation wavelength. At 414 and 330 nm, the optimum emission and excitation wavelengths were found.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAnother factor that was investigated, was pH. The influence of pH on the fluorescence intensity of the PDs was studied at room temperature for a range from pH\u0026thinsp;=\u0026thinsp;2 to 13 (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). The pH of the PDs solution affects its fluorescence intensity so that the pH values of 4 and 13 showed the highest and lowest fluorescence intensities, respectively. In general, the fluorescence intensity is higher in an acidic environment than in an alkaline solution, and in highly alkaline environments, the fluorescence intensity is greatly reduced. This property of PDs is due to the protonation of amino groups with a decrease in pH on their surfaces [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. By making the environment more acidic (pH\u0026thinsp;\u0026lt;\u0026thinsp;3), the fluorescence intensity decreases. The reason for this phenomenon is that excess acid has started to damage the dispersion of protonated PDs [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIt was also investigated how the solvent affected the PDs\u0026rsquo; fluorescence (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Although the PDs are efficiently dispersed in aqueous solutions, their polymeric structure and abundance of hydrophilic groups allow them to disperse in a variety of solvents. PDs in water, ethanol, dimethyl sulfoxide, N, N-dimethyl formamide, tetrahydrofuran, acetone, and toluene are associated with the emission peaks located at 414, 412.5, 411.5, 411, 410, and 407.5 nm, respectively.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eGenerally speaking, as the polarity of the solvent increases, the emission wavelength redshifts because the PDs dispersed in different solvents possess both different refractive indexes and different dielectric constants [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan additionalcitationids=\"CR32 CR33 CR34\" citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Moreover, the QYs of PDs dispersed in ethanol, dimethyl sulfoxide, N, N-dimethyl formamide, and acetone are more than the QY of PDs in water, and the highest QY belongs to PDs in dimethyl sulfoxide. Because PDs do not disperse well in toluene solvent, the quantum yield of PDs in this solvent is very low (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Thermo-responsive properties of the PDs\u003c/h2\u003e \u003cp\u003eThe effect of temperature on the PL intensity of the PDs is also examined. In Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea, it can be observed that when the solution temperature increases from 20 to 70\u0026deg;C, the PL intensity gradually decreases. Interestingly, a linear relationship between fluorescence intensity and temperature is achieved with a correlation coefficient of 0.9965 (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Selective detection of Fe\u003csup\u003e+\u0026thinsp;3\u003c/sup\u003e\u003c/h2\u003e \u003cp\u003eAccording to previous studies, Fe\u003csup\u003e3+\u003c/sup\u003e ion has a strong affinity for functional groups containing nitrogen and oxygen [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. As a result, the interaction of Fe\u003csup\u003e3+\u003c/sup\u003e ions with prepared PDs containing nitrogen and oxygen functional groups changes the fluorescence intensity of PDs. In other words, Fe\u003csup\u003e3+\u003c/sup\u003e ion can quench the PL of PDs. The relationship between the degree of quenching and Fe\u003csup\u003e3+\u003c/sup\u003e concentration was investigated. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea, with increasing Fe\u003csup\u003e3+\u003c/sup\u003e concentration, the fluorescence intensity decreased, and by fitting the PL (F/F\u003csub\u003e0\u003c/sub\u003e) ratio versus the Fe\u003csup\u003e3+\u003c/sup\u003e concentration in the range of 0 to 120 \u0026micro;M, a significant linear correlation with R\u0026sup2; =0.9943 was obtained (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb). The limit of detection calculated by the 3σ/k is 1.28 \u0026micro;M. In this formula, \"σ\" represents the standard deviation of blank and \"k\" represents the slope of the linear region [\u003cspan additionalcitationids=\"CR38\" citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn the table below, different carbon dots or polymer dots, which were prepared from different sources, are compared in terms of quantum yield, detection limit, and linear range of response to Fe\u003csup\u003e3+\u003c/sup\u003e with synthetic polymer dots. As can be seen, the quantum yield of PDs is high and favorable in terms of low detection limit and wide linear range.\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\u003eComparison of the salient features of PDs prepared in this work with other CDs or PDs prepared for the detection of Fe\u003csup\u003e3+\u003c/sup\u003e ions\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRow materials\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQY\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLinear range (\u0026micro;M)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLOD (\u0026micro;M)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2,5-DABS and 4-aminophenylboronic acid hydrochloride\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.44%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3 _ 546\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDopamine and ethanediamine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9.4%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50 _ 300\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCranberry beans\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10.85%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30 _ 600\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9.55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eglutamic acid and ethylenediamine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.45%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 _ 80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrunus avium fruit extract\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 _ 100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epolyethyleneimine and 5-aminosalicylic acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 _ 60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThiourea and citric acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.3 _ 5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSnake gourd peel extract\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.6%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 _ 100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCitric acid and ethylenediamine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40.87%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 _ 1200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeg 2000 and A-EDTA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e45%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0 _ 120\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eThis work\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAn interesting point is that the rate of quenching of polymers by iron is very high; therefore, after 1 min of interaction, no noticeable difference in the rate of quenching of polymers is observed. (Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e). So, the detection process of Fe\u003csup\u003e3+\u003c/sup\u003e can be ended within a few minutes.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo study the selectivity of PDs, different ions were tested instead of Fe\u003csup\u003e3+\u003c/sup\u003e under completely similar conditions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e, none of the ions significantly reduced the fluorescence intensity of the PDs. Only Fe\u003csup\u003e3+\u003c/sup\u003e ions successfully quenched the PL intensity of the PDs.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe reliability of this assay was confirmed by the quantitative detection of Fe\u003csup\u003e3+\u003c/sup\u003e in local tap water. We prepared three spiked samples with diverse quantities of Fe\u003csup\u003e3+\u003c/sup\u003e. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the outcomes were very satisfactory, and the recoveries ranged from 94.05 to 106.4%, which proves the practicality and applicability of the assay.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMeasurement of Fe\u003csup\u003e3+\u003c/sup\u003e ions in tap water samples\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=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSamples\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSpiked (\u0026micro;M)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFound (\u0026micro;M)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRecovery (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e28.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e56.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e94.05\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e95.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e106.4\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"},{"header":"Conclusions","content":"\u003cp\u003eIn summary, the brown fluorescent polymer dots with excitation-independent emission, high quantum yield (45%), and excellent water dispersibility were synthesized by a simple hydrothermal process. The prepared PDs were applied as a fluorescence probe that can selectively and quantitatively detect Fe\u003csup\u003e3+\u003c/sup\u003e ions with high sensitivity in the range of 0-120 \u0026micro;M with the appropriate LOD of 1.28 \u0026micro;M. In addition, the PDs display good temperature response performance in the range of 20\u0026ndash;70\u0026deg;C. Therefore, the fluorescent PDs can be applied for precise quantitative measurement of both temperature and Fe\u003csup\u003e3+\u003c/sup\u003e ions.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge the University of Tabriz.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eConflicts of interest or competing 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\u0026nbsp;\u003cstrong\u003eData and code availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eSupplementary information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eEthical approval\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot Applicable\u003cstrong\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eTuelue M, Geckeler KE. \u003cem\u003eSynthesis and properties of hydrophilic polymers. Part 7. Preparation, characterization and metal complexation of carboxy‐functional polyesters based on poly (ethylene glycol).\u003c/em\u003e Polymer international, 1999. \u003cstrong\u003e48\u003c/strong\u003e(9): p. 909-914.\u003c/li\u003e\n\u003cli\u003eHentze, M.W., et al., \u003cem\u003eTwo to tango: regulation of Mammalian iron metabolism.\u003c/em\u003e Cell, 2010. \u003cstrong\u003e142\u003c/strong\u003e(1): p. 24-38.\u003c/li\u003e\n\u003cli\u003eQin, C., et al., \u003cem\u003eSurface catalyzed oxidative oligomerization of 17\u0026beta;-estradiol by Fe3+-saturated montmorillonite.\u003c/em\u003e Environmental science \u0026amp; technology, 2015. \u003cstrong\u003e49\u003c/strong\u003e(2): p. 956-964.\u003c/li\u003e\n\u003cli\u003eAltamura, S. and M.U. Muckenthaler, \u003cem\u003eIron toxicity in diseases of aging: Alzheimer\u0026apos;s disease, Parkinson\u0026apos;s disease and atherosclerosis.\u003c/em\u003e Journal of Alzheimer\u0026apos;s Disease, 2009. \u003cstrong\u003e16\u003c/strong\u003e(4): p. 879-895.\u003c/li\u003e\n\u003cli\u003eWang, R., et al., \u003cem\u003eA turn-on fluorescent probe based on hydroxylamine oxidation for detecting ferric ion selectively in living cells.\u003c/em\u003e Chemical Communications, 2012. \u003cstrong\u003e48\u003c/strong\u003e(43): p. 5310-5312.\u003c/li\u003e\n\u003cli\u003eBobrowski, A., K. Nowak, and J. Zarębski, \u003cem\u003eApplication of a bismuth film electrode to the voltammetric determination of trace iron using a Fe (III)\u0026ndash;TEA\u0026ndash;BrO 3\u0026minus; catalytic system.\u003c/em\u003e Analytical and bioanalytical chemistry, 2005. \u003cstrong\u003e382\u003c/strong\u003e: p. 1691-1697.\u003c/li\u003e\n\u003cli\u003eLiu, B., J. Zhuang, and G. Wei, \u003cem\u003eRecent advances in the design of colorimetric sensors for environmental monitoring.\u003c/em\u003e Environmental Science: Nano, 2020. \u003cstrong\u003e7\u003c/strong\u003e(8): p. 2195-2213.\u003c/li\u003e\n\u003cli\u003eShen, P., et al., \u003cem\u003eSynthesis of cellulose‐based carbon dots for bioimaging.\u003c/em\u003e ChemistrySelect, 2016. \u003cstrong\u003e1\u003c/strong\u003e(7): p. 1314-1317.\u003c/li\u003e\n\u003cli\u003eLu, W., et al., \u003cem\u003eEconomical, green synthesis of fluorescent carbon nanoparticles and their use as probes for sensitive and selective detection of mercury (II) ions.\u003c/em\u003e Analytical chemistry, 2012. \u003cstrong\u003e84\u003c/strong\u003e(12): p. 5351-5357.\u003c/li\u003e\n\u003cli\u003eda Silva Souza, D.R., et al., \u003cem\u003eLuminescent carbon dots obtained from cellulose.\u003c/em\u003e Materials Chemistry and Physics, 2018. \u003cstrong\u003e203\u003c/strong\u003e: p. 148-155.\u003c/li\u003e\n\u003cli\u003eDemir, B., et al., \u003cem\u003eTracking hyaluronan: molecularly imprinted polymer coated carbon dots for cancer cell targeting and imaging.\u003c/em\u003e ACS applied materials \u0026amp; interfaces, 2018. \u003cstrong\u003e10\u003c/strong\u003e(4): p. 3305-3313.\u003c/li\u003e\n\u003cli\u003eBai, Z., et al., \u003cem\u003eDual-channel fluorescence detection of mercuric (II) and glutathione by down-and up-conversion fluorescence carbon dots.\u003c/em\u003e Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2018. \u003cstrong\u003e205\u003c/strong\u003e: p. 29-39.\u003c/li\u003e\n\u003cli\u003eZhu, S., et al., \u003cem\u003eThe photoluminescence mechanism in carbon dots (graphene quantum dots, carbon nanodots, and polymer dots): current state and future perspective.\u003c/em\u003e Nano research, 2015. \u003cstrong\u003e8\u003c/strong\u003e: p. 355-381.\u003c/li\u003e\n\u003cli\u003eXia, C., et al., \u003cem\u003eEvolution and synthesis of carbon dots: from carbon dots to carbonized polymer dots.\u003c/em\u003e Advanced Science, 2019. \u003cstrong\u003e6\u003c/strong\u003e(23): p. 1901316.\u003c/li\u003e\n\u003cli\u003eSheng, Y., et al., \u003cem\u003eA label-free ratiometric fluorescence nanoprobe for ascorbic acid based on redox-modulated dual-emission signals.\u003c/em\u003e Analyst, 2019. \u003cstrong\u003e144\u003c/strong\u003e(11): p. 3511-3517.\u003c/li\u003e\n\u003cli\u003eZhu, S., et al., \u003cem\u003eHighly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging.\u003c/em\u003e Angewandte Chemie International Edition, 2013. \u003cstrong\u003e52\u003c/strong\u003e(14): p. 3953-3957.\u003c/li\u003e\n\u003cli\u003eTao, S., et al., \u003cem\u003eThe polymeric characteristics and photoluminescence mechanism in polymer carbon dots: A review.\u003c/em\u003e Materials today chemistry, 2017. \u003cstrong\u003e6\u003c/strong\u003e: p. 13-25.\u003c/li\u003e\n\u003cli\u003eSong, Y., et al., \u003cem\u003eInvestigation into the fluorescence quenching behaviors and applications of carbon dots.\u003c/em\u003e Nanoscale, 2014. \u003cstrong\u003e6\u003c/strong\u003e(9): p. 4676-4682.\u003c/li\u003e\n\u003cli\u003eJaiswal, A., S.S. Ghosh, and A. Chattopadhyay, \u003cem\u003eOne step synthesis of C-dots by microwave mediated caramelization of poly (ethylene glycol).\u003c/em\u003e Chemical communications, 2012. \u003cstrong\u003e48\u003c/strong\u003e(3): p. 407-409.\u003c/li\u003e\n\u003cli\u003eFan, R.-J., et al., \u003cem\u003ePhotoluminescent carbon dots directly derived from polyethylene glycol and their application for cellular imaging.\u003c/em\u003e Carbon, 2014. \u003cstrong\u003e71\u003c/strong\u003e: p. 87-93.\u003c/li\u003e\n\u003cli\u003eWang, C., et al., \u003cem\u003eBi-functional fluorescent polymer dots: a one-step synthesis via controlled hydrothermal treatment and application as probes for the detection of temperature and Fe 3+.\u003c/em\u003e Journal of Materials Chemistry C, 2017. \u003cstrong\u003e5\u003c/strong\u003e(2): p. 434-443.\u003c/li\u003e\n\u003cli\u003eLi, H., et al., \u003cem\u003eOne-step ultrasonic synthesis of water-soluble carbon nanoparticles with excellent photoluminescent properties.\u003c/em\u003e Carbon, 2011. \u003cstrong\u003e49\u003c/strong\u003e(2): p. 605-609.\u003c/li\u003e\n\u003cli\u003eWang, C., et al., \u003cem\u003eA hydrothermal route to water-stable luminescent carbon dots as nanosensors for pH and temperature.\u003c/em\u003e Carbon, 2015. \u003cstrong\u003e82\u003c/strong\u003e: p. 87-95.\u003c/li\u003e\n\u003cli\u003eZhu, S., et al., \u003cem\u003eThe crosslink enhanced emission (CEE) in non-conjugated polymer dots: from the photoluminescence mechanism to the cellular uptake mechanism and internalization.\u003c/em\u003e Chemical communications, 2014. \u003cstrong\u003e50\u003c/strong\u003e(89): p. 13845-13848.\u003c/li\u003e\n\u003cli\u003eLai, T., et al., \u003cem\u003eHybrid carbon source for producing nitrogen-doped polymer nanodots: one-pot hydrothermal synthesis, fluorescence enhancement and highly selective detection of Fe (III).\u003c/em\u003e Nanoscale, 2013. \u003cstrong\u003e5\u003c/strong\u003e(17): p. 8015-8021.\u003c/li\u003e\n\u003cli\u003eZhang, H., et al., \u003cem\u003eFluorescence emission of polyethylenimine-derived polymer dots and its application to detect copper and hypochlorite ions.\u003c/em\u003e ACS applied materials \u0026amp; interfaces, 2019. \u003cstrong\u003e11\u003c/strong\u003e(35): p. 32489-32499.\u003c/li\u003e\n\u003cli\u003eXia, J., et al., \u003cem\u003eHighly fluorescent carbon polymer dots prepared at room temperature, and their application as a fluorescent probe for determination and intracellular imaging of ferric ion.\u003c/em\u003e Microchimica Acta, 2017. \u003cstrong\u003e184\u003c/strong\u003e: p. 1109-1116.\u003c/li\u003e\n\u003cli\u003eArsalani, N. and S.Z. Mousavi, \u003cem\u003eSynthesis and characterization of water-soluble and carboxy-functional polyester and polyamide based on ethylenediamine-tetraacetic acid and their metal complexes.\u003c/em\u003e 2003.\u003c/li\u003e\n\u003cli\u003eDong, Y., et al., \u003cem\u003ePolyamine-functionalized carbon quantum dots for chemical sensing.\u003c/em\u003e Carbon, 2012. \u003cstrong\u003e50\u003c/strong\u003e(8): p. 2810-2815.\u003c/li\u003e\n\u003cli\u003eLiu, Y., et al., \u003cem\u003eOne-step synthesis of robust nitrogen-doped carbon dots: acid-evoked fluorescence enhancement and their application in Fe 3+ detection.\u003c/em\u003e Journal of Materials Chemistry A, 2015. \u003cstrong\u003e3\u003c/strong\u003e(34): p. 17747-17754.\u003c/li\u003e\n\u003cli\u003eMoniruzzaman, M. and J. Kim, \u003cem\u003eN-doped carbon dots with tunable emission for multifaceted application: solvatochromism, moisture sensing, pH sensing, and solid state multicolor lighting.\u003c/em\u003e Sensors and Actuators B: Chemical, 2019. \u003cstrong\u003e295\u003c/strong\u003e: p. 12-21.\u003c/li\u003e\n\u003cli\u003eReckmeier, C.J., et al., \u003cem\u003eInfluence of doping and temperature on solvatochromic shifts in optical spectra of carbon dots.\u003c/em\u003e The Journal of Physical Chemistry C, 2016. \u003cstrong\u003e120\u003c/strong\u003e(19): p. 10591-10604.\u003c/li\u003e\n\u003cli\u003eLing, Y., et al., \u003cem\u003eEnhanced emission of polyethyleneimine-coated copper nanoclusters and their solvent effect.\u003c/em\u003e The Journal of Physical Chemistry C, 2015. \u003cstrong\u003e119\u003c/strong\u003e(48): p. 27173-27177.\u003c/li\u003e\n\u003cli\u003eMukherjee, S., E. Prasad, and A. Chadha, \u003cem\u003eH-Bonding controls the emission properties of functionalized carbon nano-dots.\u003c/em\u003e Physical Chemistry Chemical Physics, 2017. \u003cstrong\u003e19\u003c/strong\u003e(10): p. 7288-7296.\u003c/li\u003e\n\u003cli\u003eLu, S., et al., \u003cem\u003eNear‐infrared photoluminescent polymer\u0026ndash;carbon nanodots with two‐photon fluorescence.\u003c/em\u003e Advanced materials, 2017. \u003cstrong\u003e29\u003c/strong\u003e(15): p. 1603443.\u003c/li\u003e\n\u003cli\u003eLi, C., et al., \u003cem\u003eRed fluorescent carbon dots with phenylboronic acid tags for quick detection of Fe (III) in PC12 cells.\u003c/em\u003e Journal of colloid and interface science, 2018. \u003cstrong\u003e526\u003c/strong\u003e: p. 487-496.\u003c/li\u003e\n\u003cli\u003eJi, C., et al., \u003cem\u003eFacile and sensitive detection of nitrogen-containing organic bases with near infrared C-dots derived assays.\u003c/em\u003e Nanomaterials, 2021. \u003cstrong\u003e11\u003c/strong\u003e(10): p. 2607.\u003c/li\u003e\n\u003cli\u003eMintz, K., et al., \u003cem\u003eCarbon dots and gold nanoparticle\u0026rsquo;s based immunoassay for detection of alpha-L-fucosidase.\u003c/em\u003e Analytica chimica acta, 2018. \u003cstrong\u003e1041\u003c/strong\u003e: p. 114-121.\u003c/li\u003e\n\u003cli\u003eForootan, A., et al., \u003cem\u003eMethods to determine limit of detection and limit of quantification in quantitative real-time PCR (qPCR).\u003c/em\u003e Biomolecular detection and quantification, 2017. \u003cstrong\u003e12\u003c/strong\u003e: p. 1-6.\u003c/li\u003e\n\u003cli\u003eLiu, Y., et al., \u003cem\u003eRed emission B, N, S-co-doped carbon dots for colorimetric and fluorescent dual mode detection of Fe3+ ions in complex biological fluids and living cells.\u003c/em\u003e ACS applied materials \u0026amp; interfaces, 2017. \u003cstrong\u003e9\u003c/strong\u003e(14): p. 12663-12672.\u003c/li\u003e\n\u003cli\u003eLi, G., et al., \u003cem\u003eNitrogen-doped carbon dots as a fluorescence probe suitable for sensing Fe 3+ under acidic conditions.\u003c/em\u003e New Journal of Chemistry, 2016. \u003cstrong\u003e40\u003c/strong\u003e(12): p. 10213-10218.\u003c/li\u003e\n\u003cli\u003eZulfajri, M., et al., \u003cem\u003eCranberry beans derived carbon dots as a potential fluorescence sensor for selective detection of Fe3+ ions in aqueous solution.\u003c/em\u003e ACS omega, 2019. \u003cstrong\u003e4\u003c/strong\u003e(13): p. 15382-15392.\u003c/li\u003e\n\u003cli\u003eChen, Y., et al., \u003cem\u003eFe3+-sensitive carbon dots for detection of Fe3+ in aqueous solution and intracellular imaging of Fe3+ inside fungal cells.\u003c/em\u003e Frontiers in Chemistry, 2020. \u003cstrong\u003e7\u003c/strong\u003e: p. 911.\u003c/li\u003e\n\u003cli\u003eEdison, T.N.J.I., et al., \u003cem\u003eTurn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging.\u003c/em\u003e Journal of Photochemistry and Photobiology B: Biology, 2016. \u003cstrong\u003e158\u003c/strong\u003e: p. 235-242.\u003c/li\u003e\n\u003cli\u003eTang, Y., et al., \u003cem\u003eOne-pot synthesis of fluorescent non-conjugated polymer dots for Fe3+ detection and temperature sensing.\u003c/em\u003e Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2020. \u003cstrong\u003e240\u003c/strong\u003e: p. 118626.\u003c/li\u003e\n\u003cli\u003eSailaja Prasannakumaran Nair, S., N. Kottam, and P.K. SG, \u003cem\u003eGreen synthesized luminescent carbon nanodots for the sensing application of Fe 3+ ions.\u003c/em\u003e Journal of Fluorescence, 2020. \u003cstrong\u003e30\u003c/strong\u003e: p. 357-363.\u003c/li\u003e\n\u003cli\u003eXiang, Z., et al., \u003cem\u003eSensitive, Selective and Reliable Detection of Fe3+ in Lake Water via Carbon Dots-Based Fluorescence Assay.\u003c/em\u003e Molecules, 2022. \u003cstrong\u003e27\u003c/strong\u003e(19): p. 6749.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"polymer dot, temperature responsive, Fe3+ detection, polyester, tap water","lastPublishedDoi":"10.21203/rs.3.rs-4459089/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4459089/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eHighly fluorescent non-conjugated polymer dots (PDs) were synthesized by an aqueous synthetic route using a hydrothermal method from polyester prepared with PEG and di-anhydride EDTA (DA-EDTA). The synthesized PDs display strong blue fluorescence with a high quantum yield (QY) of 45% in water and more than 45% in ethanol, dimethyl sulfoxide, N, N-dimethyl formamid, and acetone. The optical and structural properties of the PDs were investigated by UV\u0026ndash;Vis, fluorescence spectrophotometry, EDX, FTIR, SEM, TEM, AFM, and DLS. The PDs were used as a sensitive fluorescence probe for Fe\u003csup\u003e3+\u003c/sup\u003e ions detection, with a low detection limit of 1.28 \u0026micro;M. The linear range in which fluorescent intensity decreases with increasing Fe\u003csup\u003e3+\u003c/sup\u003e is 0-120 \u0026micro;M. Besides, in the range of 20℃ to 70 ℃, fluorescent intensity declines with increasing temperature. Therefore, it can also be used as a thermometer. The spike recovery test confirmed the practicality of the method for the analysis of Fe\u003csup\u003e3+\u003c/sup\u003e ions in tap water samples.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e","manuscriptTitle":"Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-06-05 17:52:15","doi":"10.21203/rs.3.rs-4459089/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"13de9e0e-e7db-4242-9641-68b8b9db0332","owner":[],"postedDate":"June 5th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-06-24T17:21:37+00:00","versionOfRecord":[],"versionCreatedAt":"2024-06-05 17:52:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4459089","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4459089","identity":"rs-4459089","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}