Fabrication of a biomimetic membrane with biomaterials-attached conducting polymer: application to a NADH sensor

A electrochemical sensor for ß-nicotinamide adenine dinucleotide (NADH) has been developed. To fabricate a stable sensor probe, we modified the probe surface with a conjugated polymer (5,2´:5´,2´´-terthiophene-3´-carboxylic acid, TTCA), which serves as a base substrate to construct the artificial biomembrane. The AuNPs were electrodeposited onto a carbon electrode (CE) to enhance its electrocatalytic activity, sensitivity, and stability. Cytochrome c (cyt c) and lipid (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine, DOPE) were simultaneously immobilized on the poly-TTCA/AuNPs/CE. DOPE and cyt c immobilized onto the poly-TTCA layers were 2.8 × 10^-9 and 1.8 × 10^-10 mole/cm², respectively. To improve the specific biomimetic properties, ubiquinone (UQ₁₀) was immobilized onto the modified electrode together. The characteristics of modified electrode were investigated by cyclic voltammetry, impedance spectrometry, differential pulse voltammetry, and QCM.