Ferrocene-Branched Polymers via a Ugi Multicomponent Reaction for an Integrated and Reagentless Amperometric Glucose Biosensor

A Ugi multicomponent reaction was employed to synthesize a ferrocene (Fc)-branched polyethyleneimine derivative. This polymer was evaluated as a redox-active matrix for the fabrication of an electroanalytical disposable glucose biosensor based on a carbon PE-printed electrode functionalized with glucose oxidase as a biorecognition element. The resulting biosensor displayed a linear response up to 35 mM glucose at pH 6.5, with a limit of detection of 33 µM. The enzyme biosensor reached 95% of the steady-state current within approximately 50 s and showed a sensitivity of 0.92 µA/mM. In addition, this analytical device exhibited high selectivity, good reproducibility, and excellent storage stability, retaining strong analytical performance after 45 days at 4 °C. The proposed electrochemical biosensor was successfully applied to glucose determination in red and white wine samples.