Molecularly imprinted nanocomposites-based synthetic antibodies for uric acid-specific non-invasive electrochemical gout sensors.

A disposable electrochemical sensor is introduced for the selective recognition of uric acid (UA), a crucial biomarker for gout arthritis. The sensor employs synthetic antibodies composed of molecularly imprinted polythiophene (MIP) laden graphitic carbon nitride (GCN) nanocomposites for the selective recognition of UA. Microscopic analysis demonstrates an increase in surface roughness and kurtosis after removing the template, indicating the fabrication and functionalization of the MIP/GCN sensors. These sensors exhibit excellent electrochemical properties, characterized by electrochemical impedance spectroscopy (EIS) and voltammetric (CV, DPV) methods. The sensor displays a wide linear detection range (1-500 µM), encompassing the normal UA levels in human saliva, high sensitivity (5.47 µA/cm2.µM), a low limit of detection (0.21 µM), and limit of quantification (0.64 µM). The sensor also exhibits low cross-sensitivity to common salivary interferences, including urea, creatinine, ascorbic acid, glucose, and glutamine. The MIP/GCN sensor accurately identifies UA in human saliva, resulting in a recovery of 93.25 ± 0.33%. Electrochemical studies, utilizing [Fe(CN)6]4-/3- as a redox probe, also provide insights into the mechanisms of interfacial redox reactions and selective UA recognition. This work demonstrates a significant improvement in POC testing, providing a reliable and non-invasive tool for gout diagnosis.