Aptamer Beacon Sensor for Manual and Remote Automated Microbial Detection

Building on previously successful rapid one step ldquo;bind and detectrdquo; or ldquo;lights onrdquo; 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.nbsp; High affinity DNA aptamer sequences for each of these targets already exist to facilitate the 3D modeling.nbsp; Nanohmics will determine where to place the fluorophores and quenchers within the Fouml;rster distance to best quench fluorescence and lead to a strong ldquo;lights onrdquo; 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.nbsp;