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<p>Uric acid (UA) is an important biomarker for metabolic disorders such as gout. While non-enzymatic electrochemical sensors offer superior stability and cost-effectiveness compared to enzymatic, their sensing performance is fundamentally governed by the structure and chemistry of the electrode interface. Electrodeposited reduced graphene oxide (RGO) as a structure-tailored electrochemical interface for non-enzymatic UA detection, in which the interfacial properties are systematically tuned by controlling the pH of the graphene oxide solution during electrodeposition. RGO films deposited at pH 8–10 was characterised using FESEM, EDS, AFM, XRD, Raman, and XPS to elucidate the relationships between structure and properties. The RGO interface formed at pH 9 exhibited a dense and homogeneous morphology with an optimal C:O ratio and enhanced graphitic ordering, resulting in improved conductivity and enlarged electroactive surface area. This RGO/SPGE interface with an optimised structure enabled sensitive UA detection over a concentration of 0.1–1.1&#xa0;mM, achieving a sensitivity of 315.11 µA mM⁻<sup>1</sup>&#xa0;cm⁻<sup>2</sup> and a detection limit of 7.87&#xa0;µM, with a limit of quantification (LOQ) of 26.22&#xa0;µM. The sensor was very selective against common interfering species, stable in operation (93.8% signal retention after 7&#xa0;days), and very repeatable and reproducible. All electrochemical measurements were conducted in PBS, and further validation in complex biological matrices such as serum or urine will be investigated in future studies. Electrochemical analysis revealed that UA oxidation at the tailored RGO interface proceeds via diffusion-controlled kinetics, with urate anion adsorption onto the RGO surface via π–π interactions and hydrogen bonding facilitating efficient charge transfer.</p>

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Electrodeposited Reduced Graphene Oxide as a Structure-Tailored Interface for Non-enzymatic Uric Acid Detection

  • 期刊论文

  • 发表日期：

    2026年7月22日

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  • Muhammad Haziq Ilias,
  • Zainiharyati Mohd Zain,
  • Maizatul Zolkapli,
  • Norhazlin Khairudin,
  • Muhammad Zamharir Ahmad,
  • Rozina Abdul Rani,
  • Noor Fitrah Abu Bakar,
  • Ahmad Sabirin Zoolfakar

摘要

Uric acid (UA) is an important biomarker for metabolic disorders such as gout. While non-enzymatic electrochemical sensors offer superior stability and cost-effectiveness compared to enzymatic, their sensing performance is fundamentally governed by the structure and chemistry of the electrode interface. Electrodeposited reduced graphene oxide (RGO) as a structure-tailored electrochemical interface for non-enzymatic UA detection, in which the interfacial properties are systematically tuned by controlling the pH of the graphene oxide solution during electrodeposition. RGO films deposited at pH 8–10 was characterised using FESEM, EDS, AFM, XRD, Raman, and XPS to elucidate the relationships between structure and properties. The RGO interface formed at pH 9 exhibited a dense and homogeneous morphology with an optimal C:O ratio and enhanced graphitic ordering, resulting in improved conductivity and enlarged electroactive surface area. This RGO/SPGE interface with an optimised structure enabled sensitive UA detection over a concentration of 0.1–1.1 mM, achieving a sensitivity of 315.11 µA mM⁻1 cm⁻2 and a detection limit of 7.87 µM, with a limit of quantification (LOQ) of 26.22 µM. The sensor was very selective against common interfering species, stable in operation (93.8% signal retention after 7 days), and very repeatable and reproducible. All electrochemical measurements were conducted in PBS, and further validation in complex biological matrices such as serum or urine will be investigated in future studies. Electrochemical analysis revealed that UA oxidation at the tailored RGO interface proceeds via diffusion-controlled kinetics, with urate anion adsorption onto the RGO surface via π–π interactions and hydrogen bonding facilitating efficient charge transfer.