Building on previously successful rapid one step “bind and detect” or “lights on” DNA aptamer beacon assays for bone peptides and vitamin D (NASA Tech Briefs. MSC-24619-1/5091-1, September 2013, pg. 78), Nanohmics proposes to engineer optimized aptamer beacon assays for common components of bacterial and fungal cell walls based on 3D YASARA computer models of the aptamer-target complexes. In Phase I, Nanohmics will target N-acetylglucosamine (NAG) which is common to peptidoglycan in all bacterial cell walls and chitin in all fungal cell walls as well as the KDO antigen which is common to the lipopolysaccharides (LPS) of all Gram negative bacteria. High affinity DNA aptamer sequences for each of these targets already exist to facilitate the 3D modeling. Nanohmics will determine where to place the fluorophores and quenchers within the Förster distance to best quench fluorescence and lead to a strong “lights on” fluorescence response when targets enter the aptamer binding pockets. These optimized models will then be tested empirically at Texas State University and should enhance sensitivity of the beacon assays. Ultimately in Phase II, Nanohmics will lyophilize the aptamer beacon assays for long shelf life and integrate them into a customized handheld and/or compact fluorometer for use in spacecraft cabins to detect microbial contamination on surfaces via a manual and robotic wetted swab test. The automated compact sensor will also be able to assess the safety of recycled water to determine if the water is potable and impacted air samples to assess environmental air quality remotely before re-entering Gateway or Mars space vehicles left vacant for long periods.
NASA would use this technology as a highly portable means for astronauts to quickly (10-15 minutes) assess microbial contamination on spacecraft interior surfaces, in ambient air and the recycled water supply using lyophilized and rehydrated DNA aptamer beacon assays. Monitoring of other clinical analytes such as bone loss peptides or vitamin D by NASA in serum or urine would also be possible with the same general aptamer beacon assay technology in a handheld or compact sensor platform.
On Earth there would be numerous uses of such a rapid one step portable biosensor including detection and quantitation of pathogens on hospital fomites as well as foodborne, waterborne, and other pathogens, clinical analytes, agricultural and veterinary analytes, pesticides, toxins, pollutants, and chem/bio-threat agents for homeland security, etc.