Immobilisation of enzymes on poly(aniline)–poly(anion) composite films. Preparation of bioanodes for biofuel cell applications

Immobilisation of enzymes is important for applications such as biosensors or biofuel cells. A poly(histidine) tag had been introduced on the C terminus of a lactate dehydrogenase enzyme. This mutant enzyme was then immobilised onto poly(aniline) (PANi)–poly(anion) composite films, PANi–poly(vinylsulfonate) (PVS) or PANi–poly(acrylate) (PAA). The NADH produced by the immobilised enzyme in the presence of β-nicotinamide adenine dinucleotide (NAD+) and lactate is oxidised at the poly(aniline)-coated electrode at 0.05 to 0.1 V vs. saturated calomel electrode (SCE) at 35 °C.