Ultrasensitive Specific Detection of Anti-influenza A H1N1 Hemagglutinin Monoclonal Antibody Using Silicon Nanowire Field Effect Biosensors.

Rapid and sensitive detection of virus-related antigens and antibodies is crucial for controlling sudden seasonal epidemics and monitoring neutralizing antibody levels after vaccination. However, conventional detection methods still face challenges related to compatibility with rapid, highly sensitive, and compact detection apparatus. In this work, we developed a Si nanowire (SiNW)-based field-effect biosensor by precisely controlling the process conditions to achieve the required electrical properties via complementary metal-oxide-semiconductor (CMOS)-compatible nanofabrication processes. The SiNW surface was chemically modified with 2-aminoethylphosphonic acid, followed by a dehydration condensation reaction with influenza A H1N1 hemagglutinin (HA1), to enable specific detection of anti-HA1 immunoglobulin G (IgG). We successfully detected the anti-influenza IgG with concentrations ranging from 1 aM to 100 nM, achieving a remarkable detection limit of 6.0 aM. To demonstrate specificity, a control experiment was conducted using normal mouse IgG with concentrations of 6 aM to 600 nM. The results showed a high specificity, with the signal being 6-fold greater for the target IgG compared to the control IgG. This work demonstrates the capability of SiNW biosensors to detect anti-influenza A H1N1 hemagglutinin monoclonal antibody with enhanced detection sensitivity and specificity. This work lays the groundwork for future applications in detecting antibodies after vaccination or immunotherapy, contributing to the effective management of infectious pandemics.