OmniSite BioDiagnostics Inc. (OmniSite) proposes to develop a novel DNA aptamer against glucose for the purpose of monitoring glucose levels in the rotating space bioreactor and eventually in astronauts or other human subjects. Aptamers are short (40-60 base) DNA or RNA chains selected from a randomized library for their affinity to a given immobilized target molecule (e.g., glucose). After several iterations of affinity selection followed by PCR amplification, rare high affinity oligonucleotides from the original random library emerge and dominate the nucleic acid population. If DNA aptamers are raised against glucose and then cloned and sequenced, they can be engineered with an intrachain fluorophore and quencher pair to fluoresce upon binding of glucose, because the fluorophore would be released from its quenched state (released from fluorescence resonance energy transfer; FRET). The fluorescence intensity would be proportional to the amount of glucose bound to the aptamers, thus enabling construction of a quantitative glucose sensor. Because DNA can be heated to release any bound target molecules, the sensor could be heat and flushed to make it reusable (a desirable feature for the space bioreactor to obviate frequent sensor maintenance). The entire sensor could eventually be constructed at the end of a fiber optic cable making it miniature and implantable in the bioreactor or in human subjects. POTENTIAL COMMERCIAL APPLICATIONS Clearly, if successful, this project would hold great commercial viability for the food and pharmaceutical industries for continuous or reusable (long-term) on-line sugar and metabolite monitoring in such processes as fermentations or other large-scale cell culture processes. In addition, the technology might be extremely useful as an implantable glucose sensor for humans that could be used for patients in hospitals or for in home diabetic monitoring. Other biochemically relevant targets, other than glucose, would be possible as well, making FRET-aptamers a very lucrative technology.
