Applications of microstructured porous silicon as a biocatalytic surface

The use of porous silicon (FS) as an efficient surface enlarging carrier ma trix fur immobilised enzymes is demonstrated. An optimal porous matrix in p -type silicon (10-20 Omega cm) with respect to enzymatic substrate turn-ove r was obtained when anodising the sample at 100 mA/cm(2) for 5 min. An incr ease in glucose turn-over of approximate to 220 times as compared to an enz yme activated polished surface was recorded. The hight st increase in turn- over was found to be 350 times for an n-epilayer on n(+) substrate. The app lication of glucose monitoring is demonstrated showing a linear range to 15 mM glucose with a satisfactory storage and operational stability. The use of ascorbate oxidase activated porous silicon for the elimination of ascorb ate tan electrochemical interferent) in glutamate monitoring is reported. A n upper elimination level of I mM ascorbate was found. PS is also reported as an efficient protein cleavage surface when activated with proteases. Cle avage times normally ranging between 6 and 24 h were found to be 60 s in th e microreactor. Myoglobin cleaved on a trypsin microreactor is shown with t he corresponding mass spectra having a sequence coverage of 79%.