An ultrasensitive electrochemical immunosensor for the detection of CD146 based on TiO2 colloidal sphere laden Au/Pd nanoparticles

Abstract

An ultrasensitive electrochemical immunosensor for the detection of cluster of differentiation 146 antigen (CD146) based on TiO₂ colloidal sphere laden Au/Pd nanoparticles (Au/Pd@TiO₂) was developed. In this work, reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) was applied as an electrode modifying material to modify the surface of a glassy carbon electrode (GCE). Au/Pd@TiO₂ was used as the secondary-antibody (Ab₂) label for the fabrication of the immunosensor. Amperometric response of the immunosensor for electrocatalytic reduction of hydrogen peroxide (H₂O₂) was recorded. Electrochemical impedance spectroscopy (EIS) proved that fabrication of the immunosensor was successful. The anti-CD146 primary antibody (Ab₁) was immobilized on the rGO-TEPA modified GCE by a cross-linking reagent of glutaraldehyde (GA). With Ab₁ immobilized onto the rGO-TEPA modified GCE and Ab₂ linked with Au/Pd@TiO₂, the immunosensor displayed a wide linear range (0.0050–20 ng mL⁻¹), a low detection limit (1.6 pg mL⁻¹), good reproducibility, good selectivity and acceptable stability. The designed sensing strategy may provide a potential application in the detection of other tumor markers.