Facile preparation of Prussian blue/polypyrrole hybrid nanofibers as robust peroxidase mimics for colorimetric detection of l-cysteine

Abstract

A facile and sensitive detection of L-cysteine is essential for biosensors, environmental monitoring and medical diagnosis. In this study, a simple approach has been demonstrated to prepare Prussian blue (PB)/polypyrrole (PPy) hybrid nanofibers as efficient peroxidase-like mimics for the determination of L-cysteine. α-Fe₂O₃ nanofibers act as both templates and a source of Fe³⁺ to polymerize pyrrole in an acidic environment, resulting in the formation of PB/PPy hybrid nanofibers. The as-prepared PB/PPy hybrid nanofibers show a superior catalytic activity as peroxidase mimics over α-Fe₂O₃ nanofibers. Due to the high catalytic efficiency of the resultant PB/PPy hybrid nanofibers, we have developed a simple colorimetric approach for the rapid and sensitive determination of L-cysteine with a detection limit of about 16 nM over a wide linear range from 1 to 20 μM. In addition, the detection system displays a high selectivity toward L-cysteine over other amino acids, glucose, and common ions. This work provides a new strategy for the preparation of peroxidase-like nanomaterials with improved catalytic activity, which shows great promise for application in highly sensitive detection.