A-412 Brain hemorrhage detection with a blood test based on a quantum fluorescence sensor

Background Brain hemorrhage (BH) is one of the leading causes of stroke related deaths worldwide. Early and accurate detection of brain hemorrhage is necessary for medical intervention and to lower the mortality risk. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are current gold standard techniques for BH detection but are often unable to detect early-stage hemorrhage and are with centralized settings and with limited accessibility. To address this urgent clinical need for an accessible and sensitive method of detecting BH, we propose to develop a point of care (POC) blood test for the rapid and ultrasensitive detection of BH. Methods We propose to detect BH by sensitively monitoring changes of the level of Glial Fibrillary Acidic Protein (GFAP), a key protein biomarker for BH, in blood. GFAP level in blood increases rapidly during central nervous system injury. To meet the clinical need of ultrasensitive and rapid quantitation of BH, we developed a quantum fluorescence sensor leveraging the unique quantum manipulability of nitrogen-vacancy fluorescent nanodiamonds (NV-FNDs), which offers background-free fluorescence imaging, making them ideal for ultrahigh-sensitivity detection. Microwave modulation at 2.87 GHz was used to enhance optically detected magnetic resonance (ODMR) shifts. This approach achieved background-free fluorescence detections by selectively manipulating NV? fluorescence without altering the background autofluorescence. The quantum sensor was further integrated into an automated microfluidic device for rapid and user friendly BH detections. Moreover, for real time data analysis, a deep learning algorism was applied to increase the accuracy and speed of data analysis. Results The present method demonstrated high sensitivity and specificity compared to conventional immunoassays, achieving rapid quantitation with single NV-FND label resolution. Conclusion This NV-FNP based GFAP sensor paved the way for early detections of BH at the POC settings. Future efforts will focus on the clinical validation and system optimizations, especially in resource limited environments.