Electrochemical Biosensor Based on Hairy Core-Shell Particles: Effect of Core Conductivity

In this study, the effect of the core material in hairy core-shell carriers with grafted poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) polymer brushes containing immobilized laccase from Trametes versicolor (TvL) is investigated. Conductive silver, silver-Janus, carbon nanotubes, carbon black, and insulating silica particles were chosen as core materials. These carriers are easy to handle and store, enabling reproducible sensor fabrication with a well-defined and high number of immobilized enzymes. Hydroquinone (HQ) detection in an aqueous system was chosen as a model for biosensor characterization. All systems demonstrated high catalytic efficiency, significantly suppressing the oxidation of HQ at the electrode surface and thereby providing selectivity. The sensitivity of the prepared sensors did not differ significantly among the carriers. However, the limit of detection was highly dependent on the overall conductivity of the carrier and its active surface area. Our main observation is that using highly conductive, high-surface-area carriers does not necessarily enhance sensor performance and can in fact worsen the detection limit due to the dominance of capacitive currents over faradaic ones.