FRET Aptamer-Based Glucose Sensor for the Rotating Space BioReactor

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.