Novel instrumentation for real-time monitoring using miniaturized flow systems with integrated biosensors.
General Information : The ultimate goal is the development of a Total Chemical Analysis System (TAS) incorporating integrated biosensor arrays for detection for clinical and industrial purposes. The initial objective is to design a new instrumental approach by producing a functional model for TAS. This model will combine miniaturized in-vivo sample microdialysis, ex-vivo sample transport and preparation using flow injection analysis and measurement using integrated biosensor technology for real-time measurement of clinically important analyses (particularly lactate/glucose). Critical biochemical parameters requiring in-vivo monitoring are lactate and glucose. Glucose is important in diabetes care and lactate in a broad range of clinical conditions especially during and post surgery. The project concentrates on lactate but the measurement procedures to be developed will have far wider applicability. The concept of in-vivo sampling by microdialysis and transport to an ex-vivo site for assay, facilitates the calibration of sensors in clinical usage. Once developed, the microdialysis system in conjunction with sensors could also be used in biotechnology industrial process control and environmental fields. The functional model TAS, could form the basis for prototype production with the basis for commercialization. Practical benefits to be derived from development of a miniaturized TAS include the ability to analyze samples having small volumes, increased speed of analysis and reduction in consumption of reagents which may be expensive and harmful to the environment. Achievements : Although the prototype has not yet been tried out on human patients, tests on an-aesthetes dogs have been promising. Continuous measurements of glucose and lactate compared well with those made by intermittent blood sampling and measurement using conventional instruments. The system is sensitive to normal blood levels of the chemicals as well as the raised levels found during illness. Because of the low volume of fluid in the system, changes of glucose and lactate in the body can be detected and displayed within five minutes of their occurrence. However, there are a number of problems to be solved before the prototype can be transformed into a marketable instrument. Some of these are technical, such as further miniaturization, long-term stability, and the prevention of blood clotting in the mini-shunt. But the greatest problem, now that the research project has been completed, is the need for further funding. Medical devices have to meet strict European safety standards and the development work to ensure safety and quality assurance can be very expensive. The participants hope to find an industrial partner willing to provide the necessary backing to see the project through to completion. Further applications are possible wherever rapid and continuous chemical monitoring is required, such as in the biotechnology industry, industrial process control and environmental monitoring.