Micromixers and their applications in kinetic analysis of biochemical reactions

Investigating the kinetics of biochemical reactions plays vital roles in understanding the reaction mechanism. However, many biochemical reactions occur in the time scale of millisecond or even microsecond, which is out of the time-resolution limit of traditional methods. Microfluidic mixers, also referred to micromixers, have been widely developed to resolve the kinetics of biochemical reactions, due to their short mixing time (down to microsecond scale), low sample consumption (as low as several microliters), capability of mixing high-viscosity fluids (up to 35.25 mPa s) and ease of integration with different detection techniques. In this review, we briefly introduced mixing mechanism in micromixers, and discussed the mixing principle of four main types of micromixers: hydrodynamic focusing micromixer, chaotic convection micromixer, droplet micromixer and acoustic micromixer. We then presented how these micromixers applied in investigating enzymatic constant, resolving the kinetics of biomolecule folding or studying biomolecular interactions. At last we summarized the detection technologies used in micromixers for measuring the kinetics and predicted the potential future development on micromixers. We anticipated that micromixers would attract more attentions and would advance the field of kinetics study of biochemical reactions in future.