Direct electronic detection of prostate-specific antigen in serum

A stable carbon nanotube (CNT) network device is produced, which can electronically detect the presence of human prostate specific antigen (PSA)added to calf serum. The use of a CNT network in a capacitor configuration is a simple two-terminal device rather than a more complicated three-terminal- transistor configuration. The CNT network capacitor was functionalized with Ab using a method analogous to coating an ELISA plate. Abs were adsorbed onto the surface of the CNT capacitor by two techniques, namely, ELISA and Western blot analysis. A dose-dependent measurement of PSA added to calf serum is demonstrated with a dynamic range of 1-100 ng mL-1. A CNT-based sensor can directly measure a protein in serum.