IMAGING OF CHEMILUMINESCENT REACTIONS IN MESOSCALE SILICON-GLASS MICROSTRUCTURES

Chemiluminescent reactions in mesoscale analytical structures (chips) containing micrometre-sized interconnecting channels and chambers (pL-nL total volume) were imaged. The chips were fabricated by bonding Pyrex glass to etched pieces of silicon using a high-temperature diffusive bonding technique. In initial experiments light emission from an enhanced chemiluminescent horseradish peroxidase reaction and from a peroxyoxalate reaction contained in straight channels (300 mu m wide x 20 mu deep; volume 70.2 nL) and open chambers (812 mu m wide, 400 mu m deep, 5.2 mm long) linked by channels (100 mu m wide, 20 mu m deep) to an exit and entry port were studied using a specially modified microplate holder and an Amerlite microplate luminometer. Light emission from more complex structures (two chambers interconnected by a branching channel 100 mu m wide, 20 mu m deep) filled with a solution containing alkaline phosphatase, Emerald, and CSPDTM was imaged using a Photometrics Star 1 CCD camera. Detailed investigation of the detection and spatial resolution of the signal was performed on a Berthold Luminograph LB 980 using both the enhanced chemiluminescent horseradish peroxidase reaction and a peroxyoxalate reaction. We successfully resolved light emission from silicon structures with dimensions 100 mu m wide and 20 mu m deep. These simple silicon structures served as models for more complex designs that will be used for simultaneous multi-analyte assays in which an imaging system resolves and quantitates light emission from different locations on a silicon-glass analytical device.