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

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 CaF2). 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.