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近几年,石英晶体微天平(QCM)作为一种简易、灵敏的实时监测手段,广泛地应用于研究生物活性分子之间的相互作用,其中包括蛋白质吸附动力学、抗原/抗体相互作用、DNA杂交、适配体-蛋白相互作用等领域.但是QCM作为商业化的生物传感器一直发展不顺利.主要因为QCM在液态环境中的非理想行为导致了对QCM数据分析困难.我们利用阻抗分析法对QCM的数据进行分析,分离出质量和粘弹性两种因素引起的频率改变,解决粘弹性的困扰问题.同时,我们提出了“固化水层”模型,合理地处理了溶剂的影响.在该模型的基础上发展了一种基于QCM的分子尺技术,该技术能够简便、有效地测量出固定在固-液界面的生物大分子的纳米尺寸.我们的主要工作是将“固化水层”模型拓展到三维结构的高分子基质中.我们联合QCM和表面等离子共振(SPR)技术研究基于高分子基质的蛋白质的固定,抗原/抗体识别的过程,进一步采用“固化水层”模型解释高分子的溶胀行为、羧基活化、抗体固定、抗原、抗体识别等过程.理论分析表明,结合生物分子势必排出相同体积的溶剂,由于溶剂的密度接近于蛋白质溶液的密度.从而导致“固化水层”质量增加不明显.实验上也证实了石英晶体微天平的响应主要取决于“固化水层”的厚度变化(T2-T1),而并非固定的生物分子的质量.我们利用QCM实时监测在高分子基质中IgG的固定以及IgG与anti-IgG识别的过程,并将石英晶体微天平监测的频率变化与相应的厚度变化直接关联.这一方法的建立在一定的应用范围内简化了QCM的定量分析模型,有望实现QCM作为传感器在界面物理与化学等相关领域研究中的应用.
In recent years, quartz crystal microbalance (QCM) is a simple and sensitive real-time monitoring method widely used to study the interaction between bioactive molecules, including protein adsorption kinetics, antigen / antibody interaction, DNA Hybridization, aptamer-protein interaction, etc. However, the commercialization of QCM as a biosensor has not been successful, mainly because of the unanticipated behavior of QCM in liquid environment, which makes it difficult to analyze QCM data.We use the impedance analysis QCM, the separation of the frequency changes caused by the two factors of mass and viscoelasticity to solve the problem of viscoelasticity.At the same time, we propose a “solidified water layer” model, which reasonably deals with the influence of the solvent. Based on this model, a QCM-based molecular ruler technique was developed that can easily and effectively measure the nanometer size of biological macromolecules immobilized at the solid-liquid interface. Our main task is to “ ”The model is extended to a three-dimensional polymer matrix. We combined QCM with Surface Plasmon Resonance (SPR) to study the immobilization and resistance of polymer-based proteins In addition, the “solidified water layer” model is used to explain the process of swelling, carboxyl activation, antibody fixation, antigen, antibody recognition etc. The theoretical analysis shows that the binding of biological molecules will inevitably discharge the same volume of solvent , The density of the solvent is close to the density of the protein solution, resulting in no obvious increase in the mass of the “solidified water layer.” Experiments also confirm that the response of the quartz crystal microbalance mainly depends on the thickness of the “solidified water layer” (T2-T1), but not the fixed biomolecule quality.We used QCM to monitor the immobilization of IgG and the identification of IgG and anti-IgG in the macromolecule matrix in real time, and the change of frequency monitored by the quartz crystal microbalance and the corresponding Which is directly related to the change of thickness.This method simplifies the QCM quantitative analysis model in a certain range of applications and is expected to realize the application of QCM as a sensor in the field of interface physics and chemistry.