Selectivity and Long-Term Reliability of Resonant Explosive-Vapor-Trace Detection based on Antigen-Antibody Binding

This paper reports experimental results on the selectivity and long-term reliability of the explosive-vapor-trace detection based on antigen-antibody binding on a film bulk acoustic resonator (FBAR). An FBAR coated with specific antibody was shown to be able to detect vapor trace of TNT (Trinitrotoluene) or RDX (Cyclotrimethylenetrinitramine) without any pre-concentrator [1], but its false alarm rate and long-term reliability have never been experimentally investigated. This paper confirms that the anti-TNT coated FBAR sensor indeed responds to TNT vapor very selectively with permanent resonant frequency shift, as expected since an antigen binds only to its specific antibody. Also experimentally obtained is a surprisingly long lifetime (up to a month) of the anti-TNT at room temperature.