Ti3C2Tx MXene and polyoxometalate nanohybrid embedded with polypyrrole: Ultra-sensitive platform for the detection of osteopontin

A nanohybrid of Ti3C2Tx MXene and phosphomolybdic acid (PMo12) embedded with polypyrrole (denoted as PPy@Ti3C2Tx/PMo12) was synthesized and used as the boost platform for strongly anchoring the osteopontin (OPN) aptamer to construct an impedimetric aptamer biosensor for the detection of OPN. The PPy@ Ti3C2Tx/PMo12 hybrid not only demonstrated rich-chemical functionality, relatively high crystallinity degree, and homogeneous surface morphology but also displayed desirable electrochemical activity. These features endowed the PPy@Ti3C2Tx/PMo12 hybrid with good stability, excellent biocompatibility, and strong binding force toward OPN aptamer strands. Thus, the PPy@Ti3C2Tx/PMo12 hybrid illustrated a superior electrochemical sensing to other developed bicomponent aptasensors, such as PPy@PMo12, Ti3C2Tx@PMo12, and PPy@Ti3C2Tx hybrids. The PPy@Ti3C2Tx/PMo12-based aptasensor exhibited an extremely low detection limit of 0.98 fg mL(-1), as well as high selectivity and stability, good reproducibility, acceptable regenerability, and applicability in human serum samples. This study provided a feasible, sensitive, and reliable tool for OPN detection in clinical diagnostics.