DARPA is planning for an airborne COVID detector — Defense Systems https://defensesystems.com/articles/2020/11/11/darpa-sensars-covid-detection.aspx?s=ds_121120&oly_enc_id=&m=1. Once again DARPA has chosen to ignore or is totally unaware of what they already had in-house in the DoD. Trying to get antibody or other anti-ligands to interact in the air is extremely difficult unless one uses nanoparticles. The molecular interaction of ligand and anti-ligand (antigen and antibody) in air was attempted in the past at U.S. Army Edgewood Chemical Biological Center and AFRL; it failed but nanoparticles carrying a water coating had promise spiedigitallibrary.org/conference-pro…
“Dr Andy Ellington of the University of Texas, one of the co-inventors of SELEX, unbeknownst to us, had received substantially more support than we had, from DARPA, to develop aptamer sensors for biological warfare agents. DARPA was not under the constraint of “forced collaboration” suffered by the Service Labs and their contractors. He went on to receive more money for developing aptamer “beacons”, with a consortium of other institutions and contractors, that were supposed to interact with the agents on the fly in a biological “attack” cloud and cause them to “light up” by fluorescence (from interaction with laser light) that would reveal their presence remotely. This project was doomed from the beginning for two reasons: (1) the Army had tried the approach with antibody in the early 1990’ s at Aberdeen and failed; and (2) As Dr Eric Holwitt always said, “Most of the volume of air that we are looking in for agents is empty space; it is not that the interaction is not sensitive enough, but that there is no agent with which to interact.” This would later also be a problem with standoff detectors that depended on lasers only; the cross section of the microbes diluted in a cloud was just too small to give a decent return signal, much less any natural spectra that were specific for the agent. They were lucky to just tell the difference between a dust cloud or sand storm and a biological, which just as well have been pollen or fungal spores.—-The Black Dragon Trilogy.https://a.co/e38es8z.
Nano droplets for in air interactions:
Global Biosurveillance 