Sol-gel synthesized Re_xBi_1-x-O thin films for electrochemical creatinine sensing: A facile fabrication approach

The escalating predominance of renal diseases has obliged vigorous research on developing efficient and cost-effective biosensors for creatinine, an aspirant biomarker reflecting renal health. Herein, we fabricated a highly sensitive and selective Rhenium (Re)-doped Bismuth oxide (Bi₂O₃) (Re_xBi_1-x-O) based enzymatic electrochemical creatinine biosensor. Various concentrations of Re (5%, 10%, and 20%) were mixed with Bi₂O₃ solution via facile sol-gel synthesis and deposited on an Indium Tin oxide (ITO) substrate. The detailed physicochemical and electrochemical performance of the thin film was investigated and compared at different annealing temperatures (400 °C, 500 °C, and 600 °C). The optimized Re_xBi_1-x-O thin film (Re_0.10Bi_0.90-O at 500 °C annealing temperature) depicted a limit of detection (LOD) as low as 28 μM in a concentration range of 0.05 mM–2 mM with excellent selectivity. To ensure the feasibility of the proposed creatinine sensor, its sensing performance was verified in human serum contaminated with altered creatinine concentrations, which manifested a satisfactory recovery rate. Eventually, the outstanding performance of Re_xBi_1-x-O-based enzymatic creatinine sensor indorsed it as an accountable candidate for even more complex markers detection.