Selenium-Bearing Conducting Polymer/Graphene Quantum Dot Hybrid for Enzyme Based Electrochemical Biosensor Targeting...

In this present study, an enzyme-based amperometric nanobiosensor was designed and fabricated through the immobilization of tyrosinase onto a selenium-bearing conducting polymer (poly[BDT-alt-(TP;BSe)]), in combination with NH₂-functionalized graphene quantum dots incorporating benzoselenadiazole, thienopyrroledione, and benzodithiophene moieties. The innovative nanobiosensor was developed by crosslinking the tyrosinase enzyme with the help of glutaraldehyde in a novel selenium-bearing conducting polymer and NH₂ functionalized quantum dots matrices. Various factors influencing the biosensor's performance were optimized, including the amount of NH₂-functionalized quantum dots, poly[BDT-alt-(TP;BSe)], tyrosinase, and glutaraldehyde. Under optimized experimental parameters, catechol detection was achieved across 0.1-88 µM with a detection limit of 0.023 µM. Subsequently, the designed biosensor is used to follow tyrosinase inhibition via rosmarinic acid-containing plant materials, specifically Rosmarinus officinalis. After optimization of the inhibition conditions, I₅₀ values were determined as 21 µM for Rosmarinus officinalis. This represents the first literature report utilizing electrochemical methodology with a novel conducting polymer coupled with NH₂-functionalized graphene quantum dots for tyrosinase biosensing to evaluate rosmarinic acid inhibitory effects.