Applications of Protein-Based Capacitive Biosensors for the Detection of Heavy-Metal Ions

Three different methods of using protein-based capacitive biosensors for the detection of heavy-metal ions are presented. The metal-binding proteins SmtA, S100A12, MerP and four modified MerPs were immobilised as the bio-recognition element on self-assembled monolayer-modified gold electrodes. Capacitance was measured using potential square step or electrical impedance spectroscopy. The protein-metal interaction generated changes in capacitance mainly due to a protein conformational change.