MCM-based microlaboratory for simultaneous measurement of several biochemical parameters by spectrophotometry

This paper reports on the concept, fabrication and characterization of a multi-chip module microlaboratory. The application is in the spectrophotometric analysis of human physiological fluids in a clinical setting. The system is composed of three stacked parts: (1) a central microfluidic system die containing the microchannels, which is fabricated by applying MEMS techniques to an SU-8 layer, (2) an optical filtering system on the top side, fabricated using a dielectric thin-films multilayer and (3) a detection and readout system on the bottom side, which is fabricated in a CMOS microelectronic process. The system modularity and emphasis on microfabrication provides potential for low unit cost. The application is the simultaneous and quantitative measurement of the concentration of four biochemical parameters in human physiological fluids by spectrally selective optical absorption. The intensity of the light transmitted through the physiological fluid results in an electrical output signal in the form of bit streams, which allows simple computer interfacing. A simple white light source is used for illumination, due to the optical filtering system, which makes the microlaboratory portable. The quantitative measurement of chloride, creatinine, total protein and uric acid in urine is successfully demonstrated.