Detection of influenza virus hemagglutinin with randomly immobilized anti-hemagglutinin antibody on a carbon nanotube sensor.

Carbon nanotube sensors were capable of detecting hemagglutinin binding to anti-hemagglutinin antibody immobilized on the sensor. The carbon nanotube sensors were fabricated by chemical vapor deposition method and it showed field effect transistor property. Anti-hemagglutinin antibody was immobilized by cross-linking on the reverse surface of the carbon nanotube sensor. The current between the source and the drain was measured after incubation of various concentration of hemagglutinin antigen with immobilized anti-hemagglutinin antibody. I-Vgate curve was obtained by plotting the current as a function of the potential applied to the back gate. The I-Vgate curve showed a positive shift in a manner dependent on the hemagglutinin antigen concentration after immobilization of anti-hemagglutinin while no shift was observed without immobilization of anti-hemagglutinin antibody on the surface. The sensitivity of the CNT sensor was higher than that of the QCM method even without controlling the orientation of the anti-hemagglutinin antibody. This method constitutes a new tool to analyze interactions among biomolecules on a substrate.