Abstract
In this context, we report an electrochemical penicillin sensor utilizing dendrimer-encapsulated Pt nanoparticles (Pt DENs) as electrocatalysts for the sensitive detection of penicillin. The electrochemical penicillin sensor was prepared using a screen-printed carbon electrode (SPCE), on which both Pt DEN and penicillinase were immobilized. Upon the addition of penicillin, the immobilized penicillinase catalyzes the hydrolysis of penicillin to penicilloic acid, resulting in the production of H⁺ ions which are electrochemically detected by means of the catalyzed electrochemical reduction of the generated H⁺ ions on the Pt DEN-modified SPCE surface. Specifically, we synthesized Pt DENs containing an average of 147 atoms using amine-terminated sixth-generation polyamidoamine dendrimers, which we denote as G6-NH₂(Pt147), and immobilized the Pt DENs with penicillinase enzymes onto SPCE surfaces. The resulting SPCE exhibited highly enhanced electrocatalytic activity for the electrochemical reduction of H⁺ ions, leading to significantly increased cathodic current of H⁺. Especially, the Pt DEN-modified SPCE resulted in the electrochemical detection of penicillin as low as 0.1 μM, which allowed sensitive analysis of penicillin even in human blood serum.