A sandwich-type phenolic biosensor based on tyrosinase embedding into single-wall carbon nanotubes and polyaniline nanocomposites

A sensitive biosensor for the determination of phenolic compounds was fabricated based on tyrosinase (Tyr), single-wall carbon nanotubes (SWCNTs) and polyaniline (PANI). The surface morphologies of complex films were characterized by the scanning electron microscopy (SEM) technique. Electrochemical investigation of the biosensor showed that it gave a linear response range of 2.5 × 10−7–9.2 × 10−5 and 2.5 × 10−7–4.7 × 10−4 M and detection limit of 8.0 × 10−8 and 6.0 × 10−8 M for catechol, caffeic acid, respectively. The biosensor also exhibits good sensitivity, repeatability and stability, and presents suitability to the quantification of catechol or caffeic acid in the tested samples.