CAREER: LUCO: A Noninvasive Miniaturized Blood Gas Sensor for Respiration Monitoring

Among the vital signs of human health, respiratory parameters are key indicators of the physiological status of the human body. The accurate diagnosis of respiratory diseases mandates a measure of blood gases. The determination of blood gases requires an arterial blood sample, an invasive and painful process. This procedure, however, provides only a discrete measurement of respiratory efficacy during a rapidly changing situation. Transcutaneous monitoring is a noninvasive method of continuously measuring oxygen and carbon dioxide diffused through the skin, and any changes they undergo correlate closely with changes in blood gases. The contemporary methodology for measuring transcutaneous oxygen and carbon dioxide requires a heated sensor (that may burn the skin and require frequent alteration of the sensing spot) and a costly non-portable, bulky, corded sensing unit. This project will address a critical unmet need for a cost-effective noninvasive miniaturized wearable device capable of sensing multiple blood gas parameters that provide a comprehensive picture of one’s respiratory status from a home setting. The continuous and remote tracking of vital respiratory parameters will provide relevant and accurate data that alert a caregiver and influence the course of treatment. As the proposed system enables massive longitudinal blood gas data collected in non-clinical settings, clinicians and researchers can remotely assess and measure pulmonary outcomes objectively, and clinicians can further improve the home care management of patients with a fragile respiratory status. The educational program complementing this award will support STEM engagement in schools, provide research opportunities for underrepresented groups - particularly women, train students in state-of-the-art circuits and systems, biomedical, and optics, and support the future engineering workforce.This project will create a first-of-its-kind wearable blood gas monitor for managing the home care of individuals. More specifically, the core scientific contributions will include 1) the creation of a novel miniaturized custom-designed wearable sensor that measures two modalities of blood gases; 2) identification of factors affecting sensor readings such as temperature and drift for the self-calibration of blood gas sensors; 3) the exploration of innovative electronic interfaces for a specialized analog front-end for the proposed unique sensor with heterogeneous decay time, including one with an ultra-fast response; 4) determination of the feasibility and usability of the system during real-life activities in home settings by capturing the dynamic respiratory physiological status of individuals with longitudinal data. Having the ability to sense two vital respiratory parameters (namely, transcutaneous partial pressures of oxygen and carbon dioxide) with one wearable device is unique and superior to the current practice of measuring only oxygen saturation, and fills an important gap in the miniaturization of the transcutaneous blood gas sensor for noninvasive wearable device applications. In addition, the longitudinal new data will enable new biomedical research opportunities to assess therapies and further investigate medical conditions in which oxygen and carbon dioxide play a critical role, including novel respiratory diseases that are not yet fully understood (e.g., COVID-19). Progress on enabling the affordable and scalable remote monitoring of oxygenation and ventilation at home is transformative for prospective medical and scientific research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.