This Small Business Innovation Research (SBIR) Phase I research project will develop a small, unobtrusive system for monitoring tissue blood lactate and oxygen during surgery. Blood lactate concentration is a highly sensitive measure of tissue oxygen deprivation. It is a reliable indicator of aerobic and anaerobic physical capability, monitoring the effect of surgery on different segments of the human body. The key novel component is a silicon microprobe, comparable in cross-section to a human hair, capable of being implanted into tissue during a surgical procedure. An electrochemical lactate biosensor and oxygen sensor integrated with the microprobe continuously measures lactate concentration and oxygen partial pressure so that the data could be transmitted via a battery power telemetry chip to a remote receiver. Integrating miniaturized biosensors into these unique silicon microprobes will permit continuous monitoring of lactate and oxygen using disposable low-cost patches which are painless and easy to use. Small, rugged biosensors that can be implanted into various types of tissue will have use not only in in vivo monitoring of tissue blood lactate, but also in blood gases, electrolytes, and other analytes of interest. Transmitting this data to medical personnel wirelessly would also provide a significant advance in the state of health care. Lactate-oxygen biosensors can also be widely used in military battlefield casualty care, civilian emergency response care, and athletes practice/peoples exercise monitoring. Similar biosensors for other analytes will be applicable to precise control of diabetes, control of blood levels of therapeutic drugs, and continuous physiological monitoring for point-of-care, clinical, and research purposes
