Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
Soft Matter. 2017 Apr 12;13(15):2800-2807. doi: 10.1039/c7sm00022g.
Immobilized enzymes generate net fluid flow when exposed to specific reagents in solution. Thus, they function as self-powered platforms that combine sensing and on-demand fluid pumping. To uncover the mechanism of pumping, we examine the effects of solutal and thermal buoyancy on the behavior of phosphatase-based micropumps, using a series of reactants with known thermodynamic and kinetic parameters. By combining modeling and experiments, we perform the first quantitative comparison of thermal and solutal effects in an enzyme micropump system. Despite the significant exothermicity of the catalyzed reactions, we find that thermal effects play a minimal role in the observed fluid flow. Instead, fluid transport in phosphatase micropumps is governed by the density difference between the reactants and the products of the reaction. This surprising conclusion suggests new design principles for catalytic pumps.
固定化酶在溶液中遇到特定试剂时会产生净流体流动。因此，它们作为自供电平台，将传感和按需泵送结合在一起。为了揭示泵送的机制，我们使用一系列具有已知热力学和动力学参数的反应物来检查溶质和热浮力对基于磷酸酶的微泵行为的影响。通过结合建模和实验，我们对酶微泵系统中的热和溶质效应进行了首次定量比较。尽管催化反应具有显著的放热性，但我们发现热效应在观察到的流体流动中作用很小。相反，磷酸酶微泵中的流体输送受反应物和反应产物之间的密度差控制。这一惊人的结论为催化泵提出了新的设计原则。
