Theoretical study and analytical performance of a lysozyme impedimetric microsensor based on a molecularly imprinted chitosan film

Abstract In this study, chitosan based molecularly imprinted polymer (MIP) combined with polypyrrole (PPy) conductive film was applied to develop a novel impedimetric microsensor for the sensitive detection of lysozyme (LYS). MIP-chitosan was electrodeposited with LYS as a template on a PPy film electropolymerized on a gold microlectrode. Cyclic voltammetry measurement (CV), electrochemical impedance spectrometry (EIS), FT-IR analysis and scanning electron microscopy (SEM) were carried out to characterize the resulting microsensors and to confirm the different stages in the manufacturing process. Electrochemical Impedance Spectroscopy (EIS) was used for the determination of LYS in a linear range from 2.17 × 10−11M to 3.5 × 10-6M with a low detection limit of 5 × 10-12M. EIS responses of the different micro-sensors were modeled by using mathematical model that described the phenomena at the electrode/electrolyte interface, while showing the effect of each parameter on the response signal, highlighting how LYS concentration can affect EIS parameters. Meanwhile, the microsensor showed a high sensitivity, a good selectivity, a good reproducibility, good reusability. The construction process was relatively simple and provided a rapid and economical method. The microsensor was successfully applied to detect LYS in fresh chicken-egg white sample.