Immunosensor design based on Chitosan-QDs, a nanocomposite-modified electrode for selective procalcitonin sensing in clinic analyses

A simple free labeled electrochemical immunosensor based on chitosan (CHI) and quantum dots (QDs) was developed for the determination of procalcitonin (ProCT) antigen (Ag) which can act as a target biomarker of infectious diseases. The antibodies of the ProCT biomarker were successfully incubated on the CHI-QDs platform. Electrochemical impedance spectroscopy and cyclic voltammetry were used for the evaluation and characterization of various layers coated onto the electrode. Under the optimum conditions, the electron transfer resistance (Rct) of the immunosensor was altered linearly by the ProCT concentration. The proposed immunosensor was proportional to the ProCT biomarker concentration from 0.005 to 0.35ng/mL with a calculated detection limit of 0.015 pg/mL. The proposed biosensing device also exhibited high stability and reproducibility, which can be used for the quantitative assay of the ProCT biomarker in clinic analyses.