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<p>Accurate and sensitive detection of uric acid (UA) is critically important for early diagnosis and monitoring of metabolic disorders such as gout, hyperuricemia, kidney dysfunction, and cardiovascular diseases. In this context, the development of a cost-effective, highly sensitive, and selective electrochemical sensing platform is urgently needed. Herein, we report the fabrication of a novel Nd<sub>2</sub>O<sub>3</sub>/PANI/CQD ternary composite electrode for ultrasensitive electrochemical detection of uric acid. The Nd<sub>2</sub>O<sub>3</sub> nanoparticles were first synthesized using a hydrothermal method. These nanoparticles were then combined with polyaniline (PANI) and rice husk–derived carbon quantum dots (CQDs) through ultrasonication to form the ternary composite. XRD validated the crystalline structure of Nd<sub>2</sub>O<sub>3</sub>. FTIR and XPS confirmed the successful integration of PANI and CQDs, evidenced by the presence of Nd–O, C–N, and oxygen-containing functional groups. SEM and TEM images demonstrated that Nd<sub>2</sub>O<sub>3</sub> nanoparticles were uniformly distributed within the conductive polymer matrix. BET study indicated a porosity structure that facilitates enhanced electrolyte diffusion and accessibility of active areas. Electrochemical investigations revealed a distinct oxidation peak for UA at around 0.63&#xa0;V (vs. Ag/AgCl). Under DPV, the sensor exhibited an extensive linear range from 10 nM to 100 µM, a high sensitivity of 5100 µA mM⁻¹ cm⁻², and a low detection limit of 3.2 nM. Scan-rate studies revealed a mixed adsorption–diffusion-controlled process, while simultaneous DPV measurements demonstrated excellent selectivity towards UA in the presence of ascorbic acid and dopamine with well-resolved oxidation peaks. The practical applicability of the sensor was further confirmed through successful determination of UA in human serum samples with satisfactory recovery. The electrode maintained over 96% of its current response despite the presence of ascorbic acid and dopamine, demonstrating excellent selectivity. The results demonstrated exceptional repeatability (%RSD = 0.46%), reproducibility (%RSD = 0.59%), and robust stability, with 95.4% signal retention after 30 days. The enhanced sensing performance is derived from the synergistic integration of catalytic Nd<sub>2</sub>O<sub>3</sub> nanoparticles with the conductive PANI network and surface-functionalized CQDs. Nd<sub>2</sub>O<sub>3</sub> offers several catalytic Nd³⁺ active sites, surface hydroxyl groups, and adsorption sites related to oxygen vacancies that promote uric acid oxidation, and PANI and CQDs provide effective electron-transfer pathways and improve charge transport.</p>

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Synergistic Nd2O3/PANI/CQD Hybrid Electrode for Selective and Ultrasensitive Detection of Uric acid

  • 期刊论文

  • 发表日期：

    2026年8月3日

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  • B. Mahalakshmi,
  • P. Venkatesh,
  • K. Sudhakar,
  • Absara Fdo S

摘要

Accurate and sensitive detection of uric acid (UA) is critically important for early diagnosis and monitoring of metabolic disorders such as gout, hyperuricemia, kidney dysfunction, and cardiovascular diseases. In this context, the development of a cost-effective, highly sensitive, and selective electrochemical sensing platform is urgently needed. Herein, we report the fabrication of a novel Nd2O3/PANI/CQD ternary composite electrode for ultrasensitive electrochemical detection of uric acid. The Nd2O3 nanoparticles were first synthesized using a hydrothermal method. These nanoparticles were then combined with polyaniline (PANI) and rice husk–derived carbon quantum dots (CQDs) through ultrasonication to form the ternary composite. XRD validated the crystalline structure of Nd2O3. FTIR and XPS confirmed the successful integration of PANI and CQDs, evidenced by the presence of Nd–O, C–N, and oxygen-containing functional groups. SEM and TEM images demonstrated that Nd2O3 nanoparticles were uniformly distributed within the conductive polymer matrix. BET study indicated a porosity structure that facilitates enhanced electrolyte diffusion and accessibility of active areas. Electrochemical investigations revealed a distinct oxidation peak for UA at around 0.63 V (vs. Ag/AgCl). Under DPV, the sensor exhibited an extensive linear range from 10 nM to 100 µM, a high sensitivity of 5100 µA mM⁻¹ cm⁻², and a low detection limit of 3.2 nM. Scan-rate studies revealed a mixed adsorption–diffusion-controlled process, while simultaneous DPV measurements demonstrated excellent selectivity towards UA in the presence of ascorbic acid and dopamine with well-resolved oxidation peaks. The practical applicability of the sensor was further confirmed through successful determination of UA in human serum samples with satisfactory recovery. The electrode maintained over 96% of its current response despite the presence of ascorbic acid and dopamine, demonstrating excellent selectivity. The results demonstrated exceptional repeatability (%RSD = 0.46%), reproducibility (%RSD = 0.59%), and robust stability, with 95.4% signal retention after 30 days. The enhanced sensing performance is derived from the synergistic integration of catalytic Nd2O3 nanoparticles with the conductive PANI network and surface-functionalized CQDs. Nd2O3 offers several catalytic Nd³⁺ active sites, surface hydroxyl groups, and adsorption sites related to oxygen vacancies that promote uric acid oxidation, and PANI and CQDs provide effective electron-transfer pathways and improve charge transport.