Ceramic Microsystem Incorporating a Microreactor with Immobilized Biocatalyst for Enzymatic Spectrophotometric Assays

摘要

Low-temperature cofired ceramics (LTCC) technology isna versatile fabrication technique used to construct microflownsystems. It permits the integration of several unitarynoperations (pretreatment, separation, (bio)chemical reaction,nand detection stage) of an analytical process in anmodular or monolithic way. Moreover, because of itsncompatibility with biological material, LTCC is adequatenfor analytical applications based on enzymatic reactions.nHere we present the design, construction, and evaluationnof a LTCC microfluidic system that integrates a microreactorn(internal volume, 24.28 μL) with an immobilizednu0001-galactosidase from Escherichia coli (0.479 activitynunits) and an optical flow cell to measure the product ofnthe enzymatic reaction. The enzyme was immobilized onna glyoxal-agarose support, maintaining its activity alongnthe time of the study. As a proof of concept, the LTCC-u0001-ngalactosidase system was tested by measuring the conversionnof ortho-nitrophenyl u0001-D-galactopyranoside, the substratenusually employed for activity determinations. Oncenpacked in a monolithically integrated microcolumn, thenminiaturized flow system was characterized, the operationalnconditions optimized (flow rate and injection volume),nand its performance successfully evaluated byndetermining the u0001-galactosidase substrate concentrationnat the millimolar level.