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 Acosta'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 nearlybackgroundfree 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 1013 spins (40 µL, 0.3 µM). This translates to a malarial detection threshold of ~104 parasites/µL, 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 109 spins (1 nL, 1 µM), a 4 orders of magnitude improvement over traditional portable threshold of better than 10 EPR. This dramatic improvement is enabled by the following innovations: 1. 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. 2. 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. 3. We nanofabricate gratings on the diamond surface to enhance sensoranalyte contact by >10x. Another advantage of the proposed sensor is its small size (~1 mm) and microfluidic integration, which will facilitate parallel, multichannel 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: 1. Develop nanofabrication process for the diamond EPR sensor 2. Build a benchtop prototype and validate the detection limit on an EPR standard
