Developing enzyme microreactor based on immobilization of enzyme on silicon surface inside of microreactor

By exploiting the inherent specificity of an enzyme, it is possible to develop very specific analytical systems. For this purpose immobilized enzymes are to be preferred rather than solubilized enzymes since the immobilization generally offers increased stability of the enzyme in addition to the advantage of being able to reuse the enzyme [Nielsen et al., 1990; Nielsen, 1992].
In this study, glucose oxidase is immobilized on silicon surface inside of microreactor. The enzyme microreactor where GOD is immobilized has been employed in Flow Injection Analysis (FIA) system, and used for measurement of glucose. The glucose analysis method is based on an enzymatic reaction using glucose oxidase, which converts glucose to glucono-lactone with formation of hydrogen peroxide. Finally H2O2 is detected by a chemiluminescence reaction where luminol is oxidized by H2O2, and light with maximum intensity at 430 nm is emitted. The light is followed by PMP detector, and recorded by PC. The optimum of concentration of chemicals, flow rate of sample and reagents, and the control voltage of PMP are obtained. The sensitivity and stability of enzyme microreactor have been tested.
Comparison the traditional enzyme reactors, which are rather 1). Packed-bed reactor (PBR), with the enzyme immobilized on controlled pore glass, or 2). Wall-coated tubular reactor (WCTR) with the enzyme immobilized on the inside of a nylon tube, the great advantages of enzyme microreactor over the traditional enzyme reactor are high conversion, low dispersion and small sample volume. Therefore, the enzyme microreactor is a good method for measurement of bio/chemical sample with a very small volume.
References:
Nielsen, J.; Nikolajsen, K.; Benthin, S. and Villadsen, J. (1990)
Anal. Chim Acta, 237(1990)165-175.
Nielsen, J. (1992)
Process Control and Quality, 1992, 2(4)371-384.