2012 Volume 53 Issue 9 Pages 1633-1637
Electrical immunodetection of the avian influenza A (H5N1) hemagglutinin (HA) peptide, the IN peptide, with anti-HA antibody was demonstrated using a field-effect transistor (FET) with an n-type silicon (Si) channel and a nickel (Ni) self-aligned silicide source/drain that was fabricated by a conventional top-down process. The specific binding of the IN peptide with anti-HA antibody in phosphate buffered saline (PBS) occurs on the patterned SiO2 surface through covalent linkage. Positive ions in the buffer create majority carriers in the n-type Si channel, leading to a rapid increase in current across that channel. However, specific binding of the negatively charged antigens on the SiO2 surface overlaying the Si channel results in the reduction of electrons induced in the Si channel by the positive ions, causing a significant decrease in the channel current. The settling time for obtaining a stable signal change, driven by the negatively charged antigens bound to antibody, extrapolates to approximately 32 s.