Simulation and Experiment of Quartz Crystal Microbalance for Affinity Analysis of Antibody-Antigen Interactions
Date Issued
2007
Date
2007
Author(s)
Chang, Hung-Chi
DOI
zh-TW
Abstract
This work starts with the experiment measuring the frequency shift of the lowest transwave shear mode by additional mass of NaCl on the electrode in the gas phase by QCM (Quartz Crystal Microbalance). In addition, the experimental data are compared to the preditions by Sauerbrey's equation and finite element simulation using Comsol Multiphysics. The comparisons are consistent for the adding mass of NaCl from 200ng to 2000ng.
The Human IgG1 and Anti-Human IgG1 interactions are measured in liquid phase and their affinities (the association constant ka and dissociation constant kd) are calculated to give ka=1.212×104M-1s-1 and kd=3.501×10-3s-1 because of the effect of mass transport. It is readily known that the experimenta1 ka and kd is lower than real ka and kd. So, in order to obtain the consistent transient response with the experiments, bigger ka and kd must be used in the finite element simulations. It is found that ka=3.48×104M-1s-1 and kd=1.29×10-4s-1 are adequate such that the curves of simulation is close to the curves of experiment.
Because of the effect of mass transport, real ka can't be obtained correctly from the experimental curves. Some improvements are made. We change channel volume, electrode diameter and fluid velocity respectively. Then we can learn that the new model scales are electrode diameter=1.7×10-4m, channel diameter=7×10-4m, channel highness=0.6×10-4m, inlet and outlet diameter=1×10-4m and fluid velocity= 2.12×10-2m/s respectively. As a result, new model is adopted and make the ka of simulation similar to real ka.
Subjects
石英晶體微天平
親和力
有限元素分析
Human IgG1
Anti-Human IgG1
壓電
Comsol Multiphysics
QCM (Quartz Crystal Microbalance)
Affinity
FEM (Finite Element Method)
Piezoelectric
Type
thesis
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