Department of Chemistry, Virginia Commonwealth University, Richmond, VA, USA.
Biosens Bioelectron. 2010 Feb 15;25(6):1539-43. doi: 10.1016/j.bios.2009.11.002. Epub 2009 Nov 10.
A proof-of-concept study is presented illustrating the real-time monitoring of lysozyme (Ly) adsorption on the surface of microchannels made with cyclic olefin copolymer (COC). The signal arises from changes in the surface charge upon adsorption of Ly which is monitored by pulsed streaming potentials. Because streaming potentials are electrochemical potentials resulting from the pressure-driven flow of the liquid and the surface charge of the microchannel, this approach is ideal for microfluidics. Initial adsorption rates showed a linear correlation with the bulk concentration of [Ly] in the range between 7.0 and 350 nM. Fitting of the adsorption isotherms allowed the estimation of equilibrium and rate constants of adsorption. The influence of phosphate ions on the adsorption kinetics of Ly was also investigated. Unlike the steady flow used in conventional streaming potential measurements, the present approach incorporates pulsed flow and the ability to inject finite samples into the microfluidic stream. The pulsed flow allows the use of non-reference electrodes which removes the need for special electrolytes to stabilize the electrode potentials. Likewise, the injection permits monitoring of adsorption and desorption events in real time. The label-free monitoring of these events and the high sensitivity of the adsorption kinetics of Ly to solution species found in this work indicates that this method could be applicable to study protein-protein interactions.
本文展示了一项概念验证研究，用于实时监测环烯烃共聚物（COC）微通道表面上溶菌酶（Ly）的吸附。该信号源于 Ly 吸附导致的表面电荷变化，通过脉冲流动电势进行监测。由于流动电势是由液体的压力驱动流动和微通道表面电荷产生的电化学势，因此这种方法非常适合微流控。初始吸附速率与 [Ly] 的体相浓度在 7.0 到 350 nM 之间呈线性相关。吸附等温线的拟合允许估算吸附的平衡和速率常数。还研究了磷酸盐离子对 Ly 吸附动力学的影响。与传统流动电势测量中使用的稳态流动不同，本方法结合了脉冲流动和将有限样品注入微流的能力。脉冲流动允许使用非参比电极，从而无需特殊电解质来稳定电极电势。同样，注射允许实时监测吸附和解吸事件。在这项工作中，对这些事件的无标记监测以及 Ly 吸附动力学对溶液中物质的高灵敏度表明，该方法可用于研究蛋白质-蛋白质相互作用。
