Metal Nanoparticle-Loaded Mesoporous Carbon Nanoparticles: Electrical Contacting of Redox Proteins and Electrochemical Sensing Applications

A new method to incorporate metal nanoparticles, NPs, into pores of mesoporous carbon nanoparticles, MPC NPs, is presented. MPC NPs loaded with metal ion solutions are capped with protein units. The electrochemical reduction of the pore-entrapped ions, followed by digestion of the protein caps, yields metal NPs-loaded MPC NPs electrodes. Pt NPs/MPC NPs electrodes are used for the electrocatalyzed reduction of O₂ or H₂O₂. Furthermore, the metal NPs electrically contact enzymes with the bulk electrodes, as demonstrated for glucose oxidase-capped Pt NPs/MPC NPs electrodes that electrocatalyze glucose oxidation, and for horseradish peroxidase-capped Au NPs/MPC NPs electrodes, which electrocatalyze H₂O₂ reduction.