Nanoliter electron paramagnetic resonance sensor based on diamond nanophotonics: a new tool for biomarker monitoring

DESCRIPTION provided by applicant ODMR Technologies Inc together with Victor Acostaandapos s group at University of New Mexico is developing a nanophotonic platform capable of uniquely detecting minute quantities of biomolecules The specific detection of biomolecules plays a central role in modern life science including cell systems biology high throughput drug screening and clinical oncology In addition to fluorescence microscopy nuclear magnetic resonance and radiation techniques electron paramagnetic resonance EPR has emerged as a nearly background free molecular sensing modality Proteins and other large biomolecules typically do not exhibit magnetic signatures but if tiny
molecular sized magnets are attached to them it is possible to use EPR to determine their structure and dynamics with exquisite contrast Intrinsic EPR contrast is also present in some cases For example hemozoin crystals a byproduct of malarial parasites are paramagnetic and thus their EPR detection may enable early diagnosis of malaria infection However a major obstacle in practical EPR applications is poor sensitivity Current stte of the art portable devices have detection thresholds of spins L M This translates to a malarial detection threshold of parasites L which is orders of magnitude worse than techniques based on optical microscopy In contrast our platform can detect EPR signals from biomarkers in ambient conditions with a detection threshold of better than spins nL M a orders of magnitude improvement over traditional portable threshold of better than EPR This dramatic improvement is enabled by the following innovations Traditional EPR systems detect the small net magnetization of electron spins We instead detect the nanoscale variations in their magnetization which produce orders of magnitude larger signals at ambient temperature Traditional EPR systems use microwave coils for detection We use a magneto optical diamond film to transduce the EPR signal into the optical domain ensuring higher detection efficiency We nanofabricate gratings on the diamond surface to enhance sensor analyte contact by andgt x Another advantage of the proposed sensor is its small size mm and microfluidic integration which will facilitate parallel multi channel operation This will allow for larger scale studies as well as delaying th need to clean the sensor During the proposed research program we will pursue the following research goals Develop nanofabrication process for the diamond EPR sensor Build a benchtop prototype and validate the detection limit on an EPR standard

PUBLIC HEALTH RELEVANCE The goal of the proposed research is to develop a new type of sensor to detect the type and behavior of biomolecules such as proteins with times better sensitivity than current devices The benchtop system is anticipated to be used for high throughput analysis of proteins in cell systems biology In the longer term the technology may be used in a miniature ultra sensitive sensor for malaria diagnosis