Integration of microfluidics and FT-IR microscopy for label-free study of enzyme kinetics

Abstract In this article we report on the integration of microfluidics with FT-IR microscopy for the label-free study of enzyme kinetics. The IR compatible microfluidic chip was fabricated by standard photolithography processes using a photopatternable PDMS and infrared transparent materials (Si and CaF 2 ). Chip characterization was performed with an imaging focal plane array (FPA) detector. The enzymatic oxidation of glucose catalyzed by glucose oxidase, which served as a model system, was monitored on-chip in real time in a label-free manner using FT-IR microscopy. The reference FT-IR measurements were carried out using the attenuated total reflection (ATR) accessory. Michaelis–Menten parameters for glucose-oxidase were estimated from the spectral measurements both on-chip and off-chip. The proposed microfluidic approach for enzyme reaction monitoring serves as a novel strategy for FT-IR microscopy allowing for minimal reaction volumes, measurement automation and flexibility in terms of spatial, spectral and temporal data acquisition and offers new opportunities in kinetics studies of various bio(chemical) reactions.