Capacitive immunoaffinity biosensor by using diamond-like carbon (DLC) electrode

A new capacitive biosensor based on chronoamperometry was developed by using diamond-like carbon (DLC) film as an electric isolating layer. The electrochemical properties of the DLC layered electrode were analyzed by using a cyclic voltammetry. The immunoaffinity layer was prepared by physically adsorbing the anti-horseradish peroxidase (HRP) antibodies on the DLC electrode, and the feasibility of this capacitive biosensor was tested by using HRP as a model analyte. The limit of detection (LOD) was measured to be 0.01 pg/mL, and the detection range was determined to range from less than 0.1 pg/mL to more than 1 ng/mL. The applicability of the new capacitive biosensor was demonstrated by detecting C-reactive protein(CRP) which is known as a biomarker for the inflammatory diseases.