Tetramethylbenzidine loaded PVA nanofibers strip for visual detection of hydrogen peroxide via Cu2+ catalysis and its applications

Advancements in sensor technology have facilitated the development of cost-effective and highly sensitive sensors which have significantly improved the detection of biological analytes in various fields. This study presents a novel approach for the detection of hydrogen peroxide (H₂O₂), a critical analyte in both biological and environmental systems. A simple and sensitive colorimetric sensing platform was developed based on polyvinyl alcohol (PVA) nanofibers loaded with tetramethylbenzidine (TMB). The nanofibers were characterized using scanning electron microscopy, confirming the formation of smooth, spindle-shaped fibers with diameters from 324 to 551 nm. The colorimetric detection method utilized TMB, which undergoes oxidation in the presence of H2O2 catalyzed by Cu2 + resulting in the formation of a characteristic blue color. It revealed a linear increase in absorbance corresponding to H2O2 concentrations from 3.125 to 100 µM, with a low detection limit of 2.60 µM. The system exhibited excellent specificity and selectivity for H₂O₂ with a visual color gradient scale over common biological interferents such as glutathione, L-cysteine, urea, ascorbic acid, or various ions at a concentration of 100 µM. The new colorimetric sensor was successfully used to determine the H2O2 level in human urine from healthy subjects demonstrated excellent recovery rates (96–103%). This work introduces a simple, cost-effective, and highly selective colorimetric sensor, which is capable of rapid, on-site H₂O₂ detection without reliance on complex instrumentation. Also, the electrospun PVA/TMB exhibits strong potential of nanofibers to be used as a valuable tool for medical diagnostics, environmental monitoring and other biosensing applications.