Asiaei Sasan, Smith Brendan, Nieva Patricia
Department of Mechanical and Mechatronics Engineering, University of Waterloo , Waterloo, Ontario N2L 3G1, Canada.
Biomicrofluidics. 2015 Dec 15;9(6):064115. doi: 10.1063/1.4937929. eCollection 2015 Nov.
This research reports an improved conjugation process for immobilization of antibodies on carboxyl ended self-assembled monolayers (SAMs). The kinetics of antibody/SAM binding in microfluidic heterogeneous immunoassays has been studied through numerical simulation and experiments. Through numerical simulations, the mass transport of reacting species, namely, antibodies and crosslinking reagent, is related to the available surface concentration of carboxyl ended SAMs in a microchannel. In the bulk flow, the mass transport equation (diffusion and convection) is coupled to the surface reaction between the antibodies and SAM. The model developed is employed to study the effect of the flow rate, conjugating reagents concentration, and height of the microchannel. Dimensionless groups, such as the Damköhler number, are used to compare the reaction and fluidic phenomena present and justify the kinetic trends observed. Based on the model predictions, the conventional conjugation protocol is modified to increase the yield of conjugation reaction. A quartz crystal microbalance device is implemented to examine the resulting surface density of antibodies. As a result, an increase in surface density from 321 ng/cm(2), in the conventional protocol, to 617 ng/cm(2) in the modified protocol is observed, which is quite promising for (bio-) sensing applications.
本研究报告了一种用于将抗体固定在羧基末端自组装单分子层（SAMs）上的改进偶联方法。通过数值模拟和实验研究了微流控异质免疫分析中抗体/SAM结合的动力学。通过数值模拟，反应物种（即抗体和交联剂）的传质与微通道中羧基末端SAMs的可用表面浓度相关。在主流体流动中，传质方程（扩散和对流）与抗体和SAM之间的表面反应相耦合。所开发的模型用于研究流速、偶联试剂浓度和微通道高度的影响。无量纲组，如达姆科勒数，用于比较存在的反应和流体现象，并证明观察到的动力学趋势是合理的。基于模型预测，对传统偶联方案进行了修改，以提高偶联反应的产率。采用石英晶体微天平装置检测所得抗体的表面密度。结果表明，观察到表面密度从传统方案中的321 ng/cm²增加到改进方案中的617 ng/cm²，这对于（生物）传感应用非常有前景。
