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 TiO2 nanowire (TiNW) arrays modified with molybdenum (Mo) and MoS2 flakes by a triplex “etching, doping and deposition” technique. The triply modification of TiNW arrays improved their electron transfer, and the decoration of MoS2 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 TiO2 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.