WITHDRAWN: Polycaprolactone Electrospun Nanofibers Embedded with Phosphorus-Doped g-Carbon Nitride for Rapid Detection of Xanthine

doi:10.21203/rs.3.rs-4932569/v1

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WITHDRAWN: Polycaprolactone Electrospun Nanofibers Embedded with Phosphorus-Doped g-Carbon Nitride for Rapid Detection of Xanthine

https://doi.org/10.21203/rs.3.rs-4932569/v1

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Precise monitoring of xanthine (Xn) is very crucial for preventing and managing a range of related diseases, including gout, Lesch-Nyhan syndrome, and renal failure. Despite the development of numerous electrochemical sensors for Xn monitoring, enhancing their stability, reproducibility, sensitivity, and selectivity for real-time applications remains challenging due to the need for specific binding sites and the requirement for a uniform ions flow and electrons over the exposed catalytic active sites of electrode surface. Thus, keeping in view these challenges herein we smartly constructed a novel phosphorus doped graphitic carbon nitride (P@g-C₃N₄) embedded polycaprolactone (PCL) electrospun nanofibers-based electrode for precise electrochemical monitoring of Xn. Interestingly, P@g-C₃N₄ not only provides abundant catalytic active sites but also offers binding sites such as phosphorus sites, nitrogen sites, vacancies, and functional groups, while PCL ensures a smooth and homogeneous flow of ions, resulting in sensitive, selective, and reliable monitoring of Xn. As a result, our designed system exhibits a vast linear range of 5–240 µM and higher sensitivity with detection limit of 3.9 µM. Moreover, the designed electrochemical sensor was employed to human urine samples for real-time analysis. The results revealed that the electrode exhibits excellent reusability, sensitivity, and long-term stability, making it a cost-effective and reliable tool for future applications.

Xanthine

Electrochemical sensor

Polycaprolactone

phosphorus modified g-C3N4

Electrospinning

Xanthinuria, a metabolic disorder caused by excessive excretion of xanthine (Xn) leading to the formation of stones within the urinary tract cause to renal failure [1, 2]. A worldwide issue related to health is chronic kidney disorder because the threat of last stage renal diseases and increase in cardiovascular level and premature death [3, 4]. In metabolism of human’s purine nucleotide, Xn is an intermediate in the oxidative metabolism of purines, leads to the production of uric acid which crystallize to form monosodium urate crystals, primarily in the joints and kidneys, which can cause conditions like gout and kidney stones [5, 6]. It plays a crucial role in maintaining the physiological homeostasis with normal urinary level ranging from 40–160 µM in human body [7]. Disruption in metabolic pathways of Xn have the potential to give rise to several illnesses, including metabolic syndrome, malignancies, gout, renal dysfunction, and xanthinuria [8]. Thus, early detection of xanthinuria is crucial for preventing these adverse outcomes and ensuring better patient health. Moreover, the fluctuation in concentration of xanthine typically leads to death. Therefore, the timely and precise monitoring of Xn is of utmost importance in fields of nutritional, biochemical, and clinical diagnostics [9].

Various techniques have been proposed for detection of Xn contents, including colorimetric [10], fluorometric mass spectrometry [11], High polymerization liquid chromatography [12], capillary column gas chromatography [13], and chemiluminescence [14] to ensure the precise monitoring of Xn. Majority of these methods either face the insufficient limits of detection or include complex sample preparation which makes real-time monitoring of Xn in clinical perspective [15]. On the contrary, electrochemical method has replaced the conventional methods due to its cost-effectiveness, fast and continuous monitoring with low limits of detection and high sensitivities for commercial applications [16]. However, many carbon-based nanomaterials, including carbon nanotubes [16, 17], carbon nanoparticles [18], graphene [19], and graphitic carbon nitride [20], have been extensively used due to their chemical inertness including their substantial surface-to-volume ratio, elevated conductivity, and electron mobility under ambient conditions [20]. Among these graphitic carbon nitrides (g-C₃N₄) have garnered significant interest and have been employed in diverse applications due to their ultra-thin two-dimensional structure and inherent-conjugated semiconducting properties [20]. These nitrides exhibit surface-active sites, prompt electron transfer, minimal toxicity, and excellent biocompatibility [21]. According to reported literature, modification of carbon-based materials with heteroatoms exhibits an increased proportion of electroactive sites and a larger contact area available for interactions [22]. To improve the surface property of carbon-based materials various types of heteroatoms such as S, N, P, O have been commonly used as dopants in carbon nanoparticles, significantly improve their efficiency in catalytic processes [23]. Compared with other heteroatoms, phosphorus-doped carbon materials exhibit a significantly small affinity for protons, which increases their binding properties and catalytic performance, making them effective in specific catalytic reactions [24].

Despite the potential electro-oxidation ability of these electrodes, there are still challenges that require attention in order to attain sensitive and fast monitoring of Xn with greater reliability. These challenges include the (i) inhomogeneous ions flow (ii) reliability of the fabricated material and (iii) the improper binding efficacy of analyte towards the surface of electrode. In order to address the aforementioned challenges, we have synthesized electrospun nanofibers using PCL incorporating phosphorus doped g-C₃N₄ (PCL-P@ g-C₃N₄) on the surface of nickel foam (NF). Electrospun nanofibers have garnered a significant attention in comparison with traditional fibers due to their adjustable porosity, smooth surface, efficient electron transportation and adjustable fiber diameters which increases the number of binding sites and interactions with analyte [25]. The interconnected pore structure of NF together with electrospun nanofibers facilitates efficient movement of electrons by providing sophisticated sites [26]. The P@ g-C₃N₄ exhibits a greater number of binding sites towards the analyte due to its ability to trap electrons during the oxidation of Xn. Compared to reported electrochemical sensor for detection of Xn, our designed sensor has shown (i) high sensitivity (0.716 µA/µM/ cm²) in wide range of concentration (5–240 µM) (ii) more selectivity due to strong interactions with analytes (iii) more reusable and reproducible in terms of real times applications. These findings have confirmed its potential for successful monitoring of Xn in clinical aspects.

2.1 Chemicals and Reagents:

All chemicals and solvents used in this work for synthesis and electrochemical application of electrodes were extra pure and of analytical grade. Urea (CH₄N₂O), diammonium hydrogen phosphate ((NH₄)₂HPO₄) and Xn (C₅H₄N₄O₂), Uric acid (C₅H₄N₄O₃), ascorbic acid (C₆H₈O₆) and NF were obtained from Duksan Reagents. Phosphate buffer saline (PBS) tablets (pH ~ 7.4), were purchased from Innovatiqa. Distilled water was used throughout the experiment for the preparation of solutions. The instrumental details have been provided in Supporting Information.

2.2 Preparation of g-C₃N₄

For preparation of g-C₃N₄, urea was directly pyrolyzed. In a general preparation, 10 g of urea was placed in a capped crucible then heated upto 550°C at a heating rate of 5°C/min for 3 h. Then obtained sample was cooled at room temperature. Finally, the yellowish g-C₃N₄ powder was obtained.

2.3 Preparation of P@g-C₃N₄

g- C₃N₄ was doped with phosphorus using thermal polymerization method [27]. Briefly, a 3:1 of melamine and diammonium hydrogen phosphate was weighed and grind into fine powder. Then, the mixture was placed in a furnace and calcined for 5 h at 550°C. Then the furnace was left to cool at room temperature after calcination. In order to remove any unreacted residue, the resultant sample was centrifuged and washed with ethanol and distilled water repeatedly. Finally, the subsequent product was dried at 70°C for 12 h and grind into fine powder uniformly for successive usage in an air tight container (Fig. 1).

2.4 Fabrication of PCL- P@g-C₃N₄@ NF

To prepare the electrospinning solution of PCL, dimethyl acetamide (DMAc) and acetone were used as solvents. Herein, 20% PCL solution was prepared by dissolving it in DMAc and acetone in ratio of 2:1. Then, the prepared solution was subjected to stirring at room temperature until the transparent and homogeneous solution was achieved. Then P@g-C₃N₄ was mixed with PCL solution and kept it on stirring, until a uniform mixture formation is obtained. It is important to note that the ratio 4:1 between PCL and P@g-C₃N₄ was consistently maintained throughout the process. The resultant solution mixture was then transferred into a 30 mL plastic syringe with a 20-gauge needle of stainless steel for electrospinning process. The needle tip and the collector drum were separated by a distance of 12 cm. The potential difference was set to 20 kV at flow rate of 0.5 mL/h. Then NF was wrapped over the collector drum to collect the nanofibers on the surface of NF. A compound microscope was used for the visual confirmation of electrospun nanofibers (Fig. 2).

3.1 Morphological and Compositional Analysis of Synthesized Material

The roadmap for fabricating PCL-P@g-C₃N₄ based electrospun nanofibers on the NF surface is shown in Fig. 2. Scanning electron microscopy (SEM) analysis was performed to evaluate the surface morphology of P@g-C₃N₄ and PCL-P@g-C₃N₄. SEM image of P@g-C₃N₄ shows the cavity and pore size structure with a dispersion of phosphorus on graphitic carbon nitride nanoparticles. These cavities and pores provide active sites and will act as host for the guest molecules. While PCL-P@g-C₃N₄ shows proper incorporation of P@g-C₃N₄ powder material into fibers. Additionally, integrated electrospun nanofibers over the surface of NF is clearly visible in Fig. 2. This attribute that the integration of phosphorus into g-C₃N₄ resulting in a rough surface texture, which subsequently increased its surface area and improved the morphology of fabricated fibres. Phosphorus doping not only stabilize intermediates during the reaction but also increases the surface area in addition with PCL nanofibers by providing additional active sites and smooth pathway which further improves the mobilization of electron transfer thereby, increasing the electronic conductivity of g-C₃N₄, hence, PCL-P@g-C₃N₄ serves as an active centre to promote efficient attachment of Xn.

X-ray diffraction (XRD) analysis was performed to evaluate the phase purity and crystallinity of the fabricated electrodes, g-C₃N₄, P@g-C₃N₄ and PCL-P@g-C₃N₄ (Fig. 3A). Two distinct diffraction peaks are observed around at 13.1° and 27.5°, corresponding to the (100) and (002) planes of g-C₃N₄, respectively (JCPDS card no. 50-1512). Two prominent peaks can be seen in XRD pattern of P g-C₃N₄, one at 13.3° due to the (001) plane that has an in-plane spacing of 0.675 nm and another at 27.1° due to the (002) plane with an interlayer distance of 0.315 nm JCPDS card no. 00-087-1526. The XRD peaks align well with characteristic peaks of P@g-C₃N₄ with a slight shift in the (002) peak from 27.3 to 27.1 due to more interaction with phosphorus. The doped phosphorus is very definitely not linked to the nitrogen, but to the carbon instead due to the electronegativity of Sulfur and nitrogen. This results in a partial shift in hybridization from SP² to SP³, indicating an improvement in crystallinity following with sulfur doping. The main diffraction peaks in pure PCL are located at angles 2 = 21.3 and 23.7, respectively, which correspond to crystalline phase (110) and (200) of the material [28]. The lack of g-C₃N₄ diffraction peaks for the studied samples shows that the addition of graphitic carbon nitride has no discernible impact on the PCL matrix's crystal structure and has no discernible effect on the XRD patterns, with the exception of a slight increase in crystallinity of the PCL/g-C₃N₄ blend.

Structural characteristics including stretching, bending, vibrations, and rotations in synthesized materials (gC₃N₄, p@gC₃N₄ and PCL- p@gC₃N₄) have been confirmed by using FT-IR spectroscopy (Fig. 3B). The main amines (N-H bonds) peak exists at 1630 cm^− 1 indicate the stretching vibration modes of repeating units designed from triazine along with the peak at 1550 cm^− 1. The range 1250–1450 cm^− 1 has confirmed the presence of aromatic C–N stretching while C-H interaction in aromatic rings show the peak at 890 cm^− 1 (Fig. 3B (Black line)). Bands in region of 1233–1637 cm^− 1 were observed due to presence of C = N heterocycles stretching vibrations, while C–N bonds stretching mode of vibrations are appeared at 1533 cm^− 1. Similarly, the heptazine rings bending mode which is out-of-plane shows a peak at 810 cm^− 1 [29]. N-H peak between 3100–3300 was due to stretching mode of vibrations of the uncondensed primary (–NH–) amines and secondary (–NH₂) amines present on CN heterocycles edges of amino group residues. Moreover, the phosphorus peaks were not visible in spectra of P@g- C₃N₄ due to its insignificant existence (Fig. 3B (Red line)). The PCL characteristic peaks were observed around 1734 and 732 cm^− 1 has confirmed the strong vibrational signal of -CH₂ and stretching mode of carbonyl group, respectively. The peak of absorption at 3440 cm^− 1 might attributes to stretching vibrational mode of the N-H and O-H bonds of the amine and hydroxyl groups, respectively. On the contrary, the symmetric and asymmetric stretching modes of carboxyl groups are visible at around 1390 cm^− 1 while peaks at 1730, 1190cm^− 1 indicate the existence of C-O and C = O bonds of PCL (Fig. 3B (Blue line)).

3.2 Electrochemical Behaviour of Developed Electrodes

The electrochemical study of the developed electrodes was done through cyclic voltammetry (CV) as a redox probe, which is an appropriate technique to probe the modified electrodes’ electrochemical applications [30]. The electrochemical behaviour was elucidated by comparing the anodic peak current values of all the fabricated electrodes (g-C₃N₄, P@g-C₃N₄, PCL-P@g-C₃N₄) in a PBS solution of 0.1 M containing 5 mM [Fe (CN)₆]^3−/4− within the potential range of − 0.1V to 0.4V (Fig. 4A). CV results have confirmed that the PCL-P@g-C₃N₄@NF electrode exhibits a higher peak current value (11.2 µA) compared to P @g-C₃N₄@NF (7.09 µA) and g- C₃N₄@NF (4.82 µA). Similarly, the PCL-P@g-C₃N₄@NF electrode shows a lower peak potential difference (0.27 V) as compared to P@g-C₃N₄@NF @NF (1.49 V), g- C₃N₄@NF (1.60 V). This significantly increase in current response of PCL-P@g-C₃N₄@NF electrode could be attributed to the synergistic effect of P@g- C₃N₄ nanoparticles along with the PCL nanofibers, which successfully enhances electrocatalytic efficiency of PCL- P@g- C₃N₄@NF electrode by providing a large number of electroactive sites, smooth pathways for the transfer of electrons, a large and exposed surface area, and interactions due to π − π stacking between electrolyte and composite. Electrochemical impedance spectroscopy (EIS) was performed to study the charge transfer resistance and the diffusion characteristics of PCL- P@g- C₃N₄@NF, P@g- C₃N₄, and g- C₃N₄ electrodes in 0.1 M [Fe (CN)₆] ^3−/4− (Fig. 4B). In EIS measurements, the Nyquist plots for these electrodes have two exclusive zones, the semicircle and the line, indicating the charge transfer resistance (Rct) of electrode and diffusion of the electroactive species, respectively. The small semicircle of the PCL-P@g- C₃N₄@NF electrode specifies a lower Rct value (97 Ω) than the S@g- C₃N₄ (136 Ω) and g- C₃N₄ (165 Ω) electrodes, which confirms that the PCL-P@g-C₃N₄@NF electrode shows enhanced conductivity and catalytic activity for the instant transportation of charge/ion between the electrode and electrolyte interface.

3.3 Electro-catalytic Efficacy of the Designed Electrodes Toward Xn Sensing

The electrocatalytic performance of the PCL- P@g-C₃N₄@NF, P@g-C₃N₄@NF and g- C₃N₄@NF towards Xn were further examined through CV measurements in 20 µM of Xn within the potential range of -0.1 to 0.8V. All electrodes have shown significant oxidation peak, suggesting their electrocatalytic efficacy. However, electrocatalytic efficacy at the surface of PCL-P@gC₃N₄ modified electrode is much higher in terms of peak current density in comparison to P@g-C₃N₄ and g-C₃N₄ (Fig. 4C). This indicate that our fabricated electrode PCL-P@gC₃N₄ have more sensing capability of Xn than other materials. Moreover, to monitor the concentration effects of Xn towards the designed electrode, CV was performed at varying concentration of Xn (20 µM to 80 µM) in 0.1M PBS. Results revealed that the oxidation of Xn by the working electrode in the electrochemical system has shown the significant increase with increasing concentration of Xn (Fig. 4D). The binding mechanism of PCL-P@g-C₃N₄ towards Xn is illustrated in Scheme 1 where, oxidation of Xn is initiated from amine (NH₂) group. It’s a 2electron system in which 2 electrons and protons are released and oxygen is added into xanthine from the modified electrode. Basically, nitrogen atom of Xn rich in electron density, interact with phosphorus sites on PCL-P@g-C₃N₄ via non-covalent forces such as π-π interactions, hydrogen bonding, and electrostatic attractions. These interactions induce electron transfer from Xn to the P@g-C₃N₄, leading to radical cation formation on nitrogen atom which subsequently generate the reactive intermediate. The catalytic surface of PCL-P@g-C₃N₄ facilitates this intermediate’s transformation into uric acid. Two factors responsible for the observed slight variation in peak potential: (i) the significant interaction between Xn and electrode, (ii) the disruption in diffusion processes at a higher concentration, and mass transportation, leading to shift in peak potential. The curve derived from Fig. 4D has confirmed the linear relationship in current response with increasing concentration of Xn (Inset Fig. 4D).

3.4 Sensing and Selective Efficacy of Developed (PCL-P@g-C₃N₄) of Xanthine

Developing an electrochemical sensor with high sensitivity and selectivity is consistently a significant challenge. Sensing efficacy of the designed PCL-P@gC₃N₄ electrode was studied by performing amperometric measurements with increasing concentration of Xn (5µM to 240 µM) in 0.1 M PBS solution (Fig. 5A). Amperometric current response of the modified PCL-P@gC₃N₄ electrode was measured towards the continuous addition of Xn. Findings revealed that the current response of fabricated electrode increase with increase in concentration of Xn. In order to determine the linear range, sensitivity, and the limits of detection of the modified electrode, a calibration curve derived from Fig. 5A was drawn between amperometric current vs concentration (Fig. 5B). The calibration curve shows a linear relationship with the regression equation [Ip (µA) = 0.8648 Xn + 11.43, (R² = 0.99)]. Moreover, the modified electrode has shown limits of detection of 3.9 µM and a sensitivity value of 0.716 µA/µM/ cm² within the linear range of 5–240 µM Xn (inset Fig. 5B).

3.5 Reproducibility and Reusability of Designed Electrode

While designing a reliable sensor, reusability and reproducibility are the major key factors to be considered. Therefore, to evaluate reusability and reproducibility of the modified electrode, amperometric measures have been performed electrode at applied potential of 0.57 V under the optimized parameters. Reusability of PCL-P@g-C₃N₄ electrode has been studied in 0.1 M PBS (pH = 7.5) for 10 days continuously (Fig. 6A). Results exhibit that even after 10 days, more than 91% of current response of the fabricated electrode was retained for the detection of Xn. The reusability of PCL-P@g-C₃N₄ electrodes has been confirmed by the 3.96% of relative standard deviation (RSD). The reproducibility of PCL-P@g-C₃N₄ electrode was assessed by evaluating current sensitivity of 10 different electrodes (Fig. 6B). Results depict that, the fabricated electrode has shown excellent reproducibility with RSD value of 90%. A fundamental challenge in the development of nonenzymatic electrochemical sensors is the selective monitoring of the targeted analyte in presence of other interfering species. Here In this work, the selective efficacy of the PCL-P@gC₃N₄ electrode for Xn detection was evaluated in 0.1 M PBS at an applied potential of 0.57 V, in presence of interfering species including uric acid and ascorbic acid. Notably, the results demonstrated that the designed electrochemical sensor has shown insignificant current response in presence of higher concentrations (15 µM) of ascorbic acid and uric acid, while shown a significant current response even in low concentration of Xn (5 µM) (Fig. 6C). These findings confirm that the designed electrode has shown more selective efficacy towards Xn monitoring.

3.6 Real Sample Analysis

The applicability of the designed PCL-P@g-C₃N₄ electrode in real-time application was evaluated by quantifying the Xn levels in human urine sample using amperometric analysis at applied potential (0.8 V). Initially, the amperometric analysis of the PCL-P@g-C₃N₄ electrode was observed by introducing standard solution of 5 µM Xn (two individual additions) into PBS solution (0.1 M) of 10 mL, and the current response was measured subsequently. In the next step, the amperometric analysis of the PCL-P@g-C₃N₄ electrode was measured at same conditions (Fig. 6D). Prior to conducting the analysis, the urine sample underwent a tenfold dilution using a 0.1 M PBS solution. Then, 30 µL of diluted sample of urine was added to a 10 mL PBS solution along with the addition of 5 µM Xn. The amperometric results indicates that the observed current responses for urine spike is 5.9 µA which is is comparatively higher than standard solution of 5 µM Xn (4.3 µA). This increase in current response attributes to strong interaction of the designed electrode with Xn. These results clearly show that the modified sensor offers more reliability in future perspectives.

An electrochemical sensor based on phosphorus-doped graphitic carbon nitride (P@g-C₃N₄) has been developed for the early diagnosis of xanthinuria by detecting excess Xn levels. The synthesize of P@g-C₃N₄ was done using simple thermal polymerization method and subsequently integrated into PCL nanofibers. While doping with phosphorus has shown a significant increase in electroactive surface area, and incorporation of PCL nanofibers enhanced the electrode ion mobility and electrocatalytic activity. This study demonstrated that the engineered electrochemical sensor exhibited excellent electrocatalytic behavior, facilitate to steady flow of electrons at electrode-electrolyte interface. The sensor showed remarkable electrocatalytic performance, stability, reproducibility, and high selectivity towards Xn. Sensitivity of the designed sensor 0.716 µA/µM/ cm^− 2 has confirmed the high conductivity, and robust electrocatalytic behavior of the PCL-P@g-C₃N₄ towards Xn. Moreover, the simple configuration of the sensor, ease of fabrication without using binding agents, and outstanding electrochemical performance make this sensor a promising candidate for electrochemical analysis of Xn in urine sample. The rapid, simple approach and enhanced sensitivity suggest that this sensor holds significant potential in clinical applications for the future.

Ethical Approval
The ethical approval has been taken with details Publi/01/22 (IRB/IRC, Ibn e Sina Research Institute, Multan Medical and Dental College, Multan, Pakistan).

Funding

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through Small Groups Project under Grant number (RGP.1/41/43).

Author Contribution

Hafsah Akhtar: Writing – original draft, Software, Methodology. Sehrish Hanif: Writing – review & editing, Validation. Fahad Hussain Alhamoudi: Investigation, Funding acquisition. Anam Zulfiqar: Writing review & editing, Software. Ather Farooq Khan: Writing – review & editing, Validation, Software. Naeem Akhtar: Writing – review & editing, Writing – original draft, Conceptualization. Hamad Khalid: Writing – review & editing, Conceptualization. Nosherwan Adil: Writing review & editing, Software. Cong Yu: Conceptualization, Supervision, Validation, Visualization, Writing – review & editing.

Acknowledgement

The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through Small Groups Project under Grant number (RGP.1/41/43).Pakistan Science Foundation (PSF) is acknowledged for joint funding with TUBITAK (PSF/TUBITAK III/Bimedics/P/COMSATS (21)) awarded to Dr. Hamad Khalid.

Availability of data and materials

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Zennaro C et al (2017) The renal phenotype of allopurinol-treated HPRT-deficient mouse. PLoS ONE 12(3):e0173512
Hayat K et al (2020) CuO hollow cubic caves wrapped with biogenic N-rich graphitic C for simultaneous monitoring of uric acid and xanthine. ACS Appl Mater Interfaces 12(42):47320–47329
Gansevoort RT et al (2013) Chronic kidney disease and cardiovascular risk: epidemiology, mechanisms, and prevention. Lancet 382(9889):339–352
Al-Sulami AI et al (2024) C-entrapped Cu nanoparticles-infused polyaniline-modified cellulose nanofibers for the precise monitoring of xanthine in urine samples. New J Chem 48(6):2817–2824
Yang Q et al (2019) Anti-hyperuricemic and anti-gouty arthritis activities of polysaccharide purified from Lonicera japonica in model rats. Int J Biol Macromol 123:801–809
Hayat K et al (2020) H2O2 Screening from Saliva of Gum Diseased-patient through CN‐dot Wrapped Cu2O Nano‐frogspawns Ionic Liquid Nanocomposite. Electroanalysis 32(8):1664–1670
Andersson K-E, Arner A (2004) Urinary bladder contraction and relaxation: physiology and pathophysiology. Physiol Rev 84(3):935–986
Soory M (2009) Relevance of nutritional antioxidants in metabolic syndrome, ageing and cancer: potential for therapeutic targeting. Infectious Disorders-Drug Targets (Formerly Current Drug Targets-Infectious Disorders). 9(4):400–414
Asif M et al (2018) A review on electrochemical biosensing platform based on layered double hydroxides for small molecule biomarkers determination. Adv Colloid Interface Sci 262:21–38
Li D, Zhao J, Li S (2014) High-performance liquid chromatography coupled with post-column dual-bioactivity assay for simultaneous screening of xanthine oxidase inhibitors and free radical scavengers from complex mixture. J Chromatogr A 1345:50–56
Sen S, Sarkar P (2020) A simple electrochemical approach to fabricate functionalized MWCNT-nanogold decorated PEDOT nanohybrid for simultaneous quantification of uric acid, xanthine and hypoxanthine. Anal Chim Acta 1114:15–28
Glöckner G (1987) Polymer characterization by liquid chromatography. Elsevier
Barwick VJ (1999) Sources of uncertainty in gas chromatography and high-performance liquid chromatography. J Chromatogr A 849(1):13–33
Liu M et al (2016) Proximity hybridization-regulated chemiluminescence resonance energy transfer for homogeneous immunoassay. Talanta 154:455–460
Rogers MJ et al (2021) Membrane technology for rapid point-of-care diagnostics for parasitic neglected tropical diseases. Clin Microbiol Rev 34(4):e00329–e00320
Kalambate P et al (2022) Progress, challenges, and opportunities of two-dimensional layered materials based electrochemical sensors and biosensors. Mater Today Chem 26:101235
Pumera M (2007) Electrochemical properties of double wall carbon nanotube electrodes. Nanoscale Res Lett, 2
Baptista FR et al (2015) Recent developments in carbon nanomaterial sensors. Chem Soc Rev 44(13):4433–4453
Baig N, Sajid M, Saleh TA (2019) Recent trends in nanomaterial-modified electrodes for electroanalytical applications. TRAC Trends Anal Chem 111:47–61
Zhang L et al (2020) Electrochemical sensor based on an electrode modified with porous graphitic carbon nitride nanosheets (C 3 N 4) embedded in graphene oxide for simultaneous determination of ascorbic acid, dopamine and uric acid. Microchim Acta 187:1–10
Kumar P et al (2023) Multifunctional carbon nitride nanoarchitectures for catalysis. Chem Soc Rev 52(21):7602–7664
Jia Y, Yao X (2023) Defects in carbon-based materials for electrocatalysis: synthesis, recognition, and advances. Acc Chem Res 56(8):948–958
Yuan Y et al (2020) Heteroatom-doped carbon-based materials for lithium and sodium ion batteries. Energy Storage Mater 32:65–90
Quílez-Bermejo J, Morallón E, Cazorla-Amorós D (2020) Metal-free heteroatom-doped carbon-based catalysts for ORR: A critical assessment about the role of heteroatoms. Carbon 165:434–454
Liu R et al (2022) Progress of fabrication and applications of electrospun hierarchically porous nanofibers. Adv Fiber Mater 4(4):604–630
Lei Y et al (2020) Electrospun inorganic nanofibers for oxygen electrocatalysis: design, fabrication, and progress. Adv Energy Mater 10(45):1902115
Sammaljärvi J et al (2012) Free radical polymerisation of MMA with thermal initiator in brick and Grimsel granodiorite. Eng Geol 135:52–59
Gupta B, Geeta, Ray AR (2012) Preparation of poly (ε-caprolactone)/poly (ε‐caprolactone‐co‐lactide)(PCL/PLCL) blend filament by melt spinning. J Appl Polym Sci 123(4):1944–1950
Yang X et al (2016) Facile fabrication of acidified g-C3N4/g-C3N4 hybrids with enhanced photocatalysis performance under visible light irradiation. Appl Catal B 193:22–35
Fatima M et al (2024) Design and fabrication of machine learning trained silver nanoparticles-infused multi-walled carbon nanotube-based sensor for antiviral drug monitoring. Microchem J 203:110921

Scheme 1 is available in the Supplementary Files section.

No competing interests reported.

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Graphical Abstract
floatimage2.png
Scheme 1. The schematic representation of electrochemical detection of Xn from urine sample.
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WITHDRAWN: Polycaprolactone Electrospun Nanofibers Embedded with Phosphorus-Doped g-Carbon Nitride for Rapid Detection of Xanthine

Status:

Version 1

Editorial Note

Abstract

Figures

1. Introduction

2 Experimental Section

2.1 Chemicals and Reagents:

2.2 Preparation of g-C₃N₄

2.3 Preparation of P@g-C₃N₄

2.4 Fabrication of PCL- P@g-C₃N₄@ NF

3 Results and Discussion

3.1 Morphological and Compositional Analysis of Synthesized Material

3.2 Electrochemical Behaviour of Developed Electrodes

3.3 Electro-catalytic Efficacy of the Designed Electrodes Toward Xn Sensing

3.4 Sensing and Selective Efficacy of Developed (PCL-P@g-C₃N₄) of Xanthine

3.5 Reproducibility and Reusability of Designed Electrode

3.6 Real Sample Analysis

Conclusion

Declarations

Ethical Approval
The ethical approval has been taken with details Publi/01/22 (IRB/IRC, Ibn e Sina Research Institute, Multan Medical and Dental College, Multan, Pakistan).

Funding

Author Contribution

Acknowledgement

Availability of data and materials

References

Scheme

Additional Declarations

Supplementary Files

Status:

Version 1

WITHDRAWN: Polycaprolactone Electrospun Nanofibers Embedded with Phosphorus-Doped g-Carbon Nitride for Rapid Detection of Xanthine

Status:

Version 1

Editorial Note

Abstract

Figures

1. Introduction

2 Experimental Section

2.1 Chemicals and Reagents:

2.2 Preparation of g-C3N4

2.3 Preparation of P@g-C3N4

2.4 Fabrication of PCL- P@g-C3N4@ NF

3 Results and Discussion

3.1 Morphological and Compositional Analysis of Synthesized Material

3.2 Electrochemical Behaviour of Developed Electrodes

3.3 Electro-catalytic Efficacy of the Designed Electrodes Toward Xn Sensing

3.4 Sensing and Selective Efficacy of Developed (PCL-P@g-C3N4) of Xanthine

3.5 Reproducibility and Reusability of Designed Electrode

3.6 Real Sample Analysis

Conclusion

Declarations

Ethical Approval The ethical approval has been taken with details Publi/01/22 (IRB/IRC, Ibn e Sina Research Institute, Multan Medical and Dental College, Multan, Pakistan).

Funding

Author Contribution

Acknowledgement

Availability of data and materials

References

Scheme

Additional Declarations

Supplementary Files

Status:

Version 1

2.2 Preparation of g-C₃N₄

2.3 Preparation of P@g-C₃N₄

2.4 Fabrication of PCL- P@g-C₃N₄@ NF

3.4 Sensing and Selective Efficacy of Developed (PCL-P@g-C₃N₄) of Xanthine

Ethical Approval
The ethical approval has been taken with details Publi/01/22 (IRB/IRC, Ibn e Sina Research Institute, Multan Medical and Dental College, Multan, Pakistan).