Specific biosensing using carbon nanotubes functionalized with gold nanoparticle–antibody conjugates

This study demonstrates the electrical detection of protein binding by the introduction of Au nanoparticle–antibody conjugates in a carbon nanotube field effect transistor (CNTFET), in which the nanoparticle-functionalized carbon nanotube serves as the electrical conducting channel. Antibody (anti-horseradish peroxidase) and antigen (horseradish peroxidase) binding events lead to the amplitude change in the drain current, which can be sensitively detected by FET measurements. The sensor shows negligible response to mismatched proteins such as Immunoglobulin G (IgG), confirming the specificity of the biosensor. The reported CNTFET-based biosensor could be adapted to detect a variety of proteins for in vitro diagnostics.