TiO2 nanowire arrays modified with a simultaneous “etching, doping and deposition” technique for ultrasensitive amperometric immunosensing

In this work, an ultrasensitive immunosensing scaffold was structured with TiO 2 nanowire (TiNW) arrays modified with molybdenum (Mo) and MoS 2 flakes by a triplex “etching, doping and deposition” technique. The triply modification of TiNW arrays improved their electron transfer , and the decoration of MoS 2 flakes on TiNW arrays increased both the conductivity and the specific surface area of TiNW. Accordingly, the triply modified TiNW arrays provided a biocompatible microenviroment for the biomolecules and high specific surface area to load big amount of biomolecules . The immunosensor was prepared by immobilizing capture antibody on the scaffold surface with double amino-reactive crosslinker , and the tracing labels were prepared by immobilizing signal antibody and horseradish peroxidase molecules on cylinder-shaped TiO 2 nanorods . After sandwich-type immunoreaction, the tracing labels were quantitatively captured on the immunosensor surface for the detection of carcinoembryonic antigen as a model analyte. This amperometric method showed a linear range of 0.001 and 150   ng   mL −1 with a detection limit of 0.5   pg   mL −1 . This work provided a promising platform for sensitive amperometric immunosensing of protein biomarkers.