Disposable Immunosensor Based on Electrochemiluminescence for Ultrasensitive Detection of Ketamine in Human Hair

Abstract

An ultrasensitive disposable immunosensor based on a gold nanoparticles (AuNPs)/indium tin oxide (ITO) substrate has been constructed to detect ketamine (KET) conveniently. In this study, we obtained a AuNPs/ITO basic electrode by only a two-step ecofriendly drip-coating procedure. The self-assembled monolayers of AuNPs were used as a hetero-bifunctional cross-linker and activator, respectively. Ketamine antibody was used as a biorecognition determinant and immobilized onto the AuNPs/ITO through electrostatic interaction or Au–S or Au–N bonds. The architectures of AuNPs/ITO were characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy mainly. Electrochemiluminescence (ECL) was used to monitor the specific immune response between the antigen and antibody by measuring changes of intensity in the process of ECL. When the immune complex was incubated on the electrode, it blocked the electron communication and mass transfer,...