Redundant Multimode Chemo-optical Transducers
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CBET - 1403002Implantable sensors hold promise to improve quality of life, but their application has been limited due to inadequate accuracy. Sensor arrays (redundant sensors) offer potential to help manage operational problems and provide intrinsic error-checking. This group proposes to apply their experience in developing optical chemical sensors to pursue "multimode" sensors that enable this by combining signal generation tools - two different sensing elements, that use different interactions with the target biochemical to convert concentration into an optical signal. In addition we will develop strategies to have sensors responding to a molecular signal over a wide range of concentrations. Proposed technologies will make implantable sensors for reliable and will help develop tools for continuous monitoring of patients'' health status.Technical summary:Biosensing technology has benefited tremendously from the rapid advancement in nanotechnology, both in new nanocomposite materials as well as exploitation of unique nanoscale phenomena. However, devices for long-term monitoring have not been realized, primarily due to inadequate performance of current implantable chemical sensor technology. The barriers to advancement in this field include (1) Unreliable sensor response that varies with tissue environment and requires frequent calibration; (2) Lack of redundancy and multimodal analyses to provide intrinsic error-checking; and (3) Limited options for quantum advances using current technology. Tiny implants to generate and amplify the small optical signals hold promise for long-term success. However, each approach to convert the concentration of an analyte into an optical signal (the "chemo-optical" transducer element) has drawbacks that challenge its use. We propose that these limitations may be addressed through a combination of modalities, enabling both improved accuracy as well as error-checking capability. By using micro/nanoscale sensing components, the creation of implants with redundant sensing regions is also possible. Therefore, it is proposed to design sensors to simultaneously produce fluorescence and surface-enhanced Raman (SERS) signals that vary directly and inversely with analyte concentration, respectively. The responses are complementary and provide a means of error-checking. Using glucose as a model analyte, sensors with regions that rely on different transduction schemes (affinity binding vs. enzymatic), yielding different sensitivities, will be developed. All signals may be multiplexed to enable interrogation of the same implant region; spatially discrete regions provide redundancy.