Protein-assisted biomimetic synthesis of nanoscale gadolinium-integrated polypyrrole for synergetic and ultrasensitive electrochemical assays of nicardipine in biological samples

Electrically conductive polymer nanomaterials signify a promising class of sensing platforms in the field of electrochemistry, but their applications as electrocatalysts are commonly limited by their poor colloidal stability in aqueous media and large particle sizes. Inspired by biomineralization approaches for integrating nanoscale materials, herein, a gadolinium (Gd)-integrated polypyrrole (PPy) electrocatalyst (namely, BSA@PPy-Gd) was successfully prepared by choosing bovine serum albumin (BSA) as a stabilizer for biomimetic mineralization and polymerization in a "one-step" manner. BSA@PPy-Gd possesses outstanding water dispersibility, nanoscale morphology, and improved electrical conductivity. The electrocatalytic competency of the electrochemical (EC) sensing platform fabricated for the sensitive detection of nicardipine (NCD) was assessed. The synergy of remarkable conductivity, superior active surface area, and electrostatic interactions stimulated by the combination of BSA with the NH group of PPy on BSA@PPy-Gd and Gd increases the fast electron transfer at the analyte-electrode junction. The fabricated EC sensor, BSA@PPy-Gd/glassy carbon electrode (GCE), exhibits a current intensity greater than that of PPy/GCE, BSA/GCE, and bare GCE in terms of peak height at a pH of 7.0 in phosphate buffer solution. The newly fabricated EC sensing platform shows excellent electrocatalytic activities for the electroreduction of NCD in terms of a low detection limit (2 nM), good sensitivity, linear dynamic detection ranges (0.01-575 μM), operational stability, and repeatability and was also tested on rat and human serum specimens.