Convective flow reversal in self-powered enzyme micropumps.

ABSTRACT: Surface-bound enzymes can act as pumps that drive large-scale fluid flows in the presence of their substrates or promoters. Thus, enzymatic catalysis can be harnessed for “on demand” pumping in nano- and microfluidic devices powered by an intrinsic energy source. The mechanisms controlling the pumping have not, however, been completely elucidated. Herein, we combine theory and experiments to demonstrate a previously unreported spatiotemporal variation in pumping behavior in urease-based pumps and uncover the mechanisms behind these dynamics. We developed a theoretical model for the transduction of chemical energy into mechanical fluid flow in these systems, capturing buoyancy effects due to the solution containing nonuniform concentrations of substrate and product. We find that the qualitative features of the flow depend on the ratios of diffusivities ?=D(P)/D(S) and expansion coefficients ?=?(P)/?(S) of the reaction substrate (S) and product (P). If ?>1 and ?>? (or if ?<1 and ?

SUBMITTER: Ortiz-Rivera I 

PROVIDER: S-EPMC4791027 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature