For diabetes patients glucose monitoring means an important improvement of their life quality and additionally it is a $3-billion-a-year business. Continuous glucose monitoring provides gapless glucose level control, an early warning of hypoglycemia, and is intended to control insulin pumps. An upgrading to multi-parameter monitoring would not only benefit patients with severe metabolism defects but also the metabolism of diabetes patient could be better controlled by monitoring an additional parameter like lactate.
Multi-parameter monitoring devices are not commercially available, one of the complications in the integration of different biosensors using the same detecting molecule for all analytes is chemical cross talk between adjacent amperometric biosensors. Recently some integrated biosensors were published but either they were not mass producible or they were realized in an expensive silicon based technology. In addition to it most of them were not tested under monitoring conditions but their integration principles will be discussed.
As an example a low cost multi- parameter microsystem and some applications of it in clinical diagnosis will be presented. Also an overlook of non-invasive methods and (minimal) invasive methods will be given with a focus on microdialysis.
A miniaturized microanalytical device for the simultaneous monitoring of different metabolites was realized by assembling of a biosensor array produced by thin film technology with a flow-through cell produced by printed circuit board technology. The biosensor array comprises four working electrodes which can be individually configured. Glucose and lactate devices were made for whole blood monitoring. Ex vivo experiments, performed on animals, where the device was continuously operated in an extracorporeal undiluted heparinized blood stream without loss in sensitivity for 48 hours, gave close tracing to routinely used clinical analyzers by using one point in vitro calibration.