Multiwalled Carbon Nanotube-CaCO3 Nanoparticle Composites for the Construction of a Tyrosinase-Based Amperometric Dopamine Biosensor

We report the fabrication of a highly sensitive dopamine biosensor based on the entrapment of tyrosinase into CaCO3 nanoparticles at Multiwalled Carbon Nanotube (MWCNT) electrodes. CaCO3 acts as host matrix for tyrosinase and MWCNT provides a highly porous conductive network enhancing the enzyme immobilization and the electrochemical transduction of the enzyme reaction by boosting the amplification phenomenon involved in the biosensing of catechol and dopamine. The comparison of the performance of CaCO3‐tyrosinase electrodes with and without MWCNT film clearly indicates the improvement in sensitivity and maximum current brought by the combination of MWCNTs and inorganic nanomaterials. These nanostructured hybrid bioelectrodes exhibit a high sensitivity for the detection of catechol and dopamine, namely 35.7 A mol−1 L cm−2, the detection limit for dopamine being 15 nmol L−1 with no influence of the presence of interferents, i.e. uric acid and ascorbic acid.