Biomimetic sensor based on copper-poly(cysteine) film for the determination of metronidazole

A copper-poly(cysteine) (Cu-poly(Cys)) film was successfully achieved via a simple electrochemical method and subsequently exploited as a nitroreductase mimetic for metronidazole detection. The electropolymerized film of cysteine provides a microenvironment for the enzymatic reaction while the metallic Cu acts as an active center with catalytic function. Electrochemical treatments lead to this mimetic enzyme with greatly enhanced catalytic performance, which make it suitable for the construction of biomimetic sensors. The electrocatalytic and sensing performances of the sensor based on the Cu-poly(Cys) film were evaluated in detail. Results revealed that the sensor exhibited linear response to metronidazole in the concentration range of 0.5-400 μM, with a detection limit of 0.37 μM. In addition, we applied the proposed method to detect metronidazole in an injection solution with satisfactory results, demonstrating that the Cu-poly(Cys) film is one of the promising biomimetic catalysts for electrocatalysis and relevant fields.