石英晶体微天平的新进展

石英晶体微天平（quartz crystal microbalance,QCM）是一种对界面变化敏感的仪器,它已经在物理、化学、生物学、药物学、临床医学、环境科学等学科的界面问题研究中得到了一定的应用.然而,QCM在液相下的应用和推广一直受限于QCM数据定量解释的困难.为此,科研工作者发展了多种高级的QCM,比如带阻抗分析功能的QCM（impedance QCM,i-QCM）或带能量耗散监测功能的QCM（QCM with dissipation,QCM-D）,同时还发展了许多相应的理论模型.但是,对于多数生物、化学工作者来说,这些理论过于复杂.这极大地限制了QCM的推广和潜力发挥.本文以我们小组在QCM方面的研究工作为线索,对已报道的分析方法、模型和方程按5类应用条件进行了整理,给出了明确的界定标准：它们是：1,固-气界面;2,牛顿流体;3,固-液界面的薄膜;4,固-液界面厚膜;5,固-液界面超厚膜.对于每一类情况,我们将用通俗易懂的语言描述如何对QCM数据进行简化却又保证研究精度需要的定量分析.对于液态环境下的QCM数据的分析,我们着重介绍了＂固化水层＂模型,该模型允许QCM在一定的条件下成为一把＂分子尺＂,工作范围从几个纳米到数百纳米.该分子尺在多个创新界面问题研究中得到很好的应用.最后,我们从理论上分析了QCM作为生物传感器的先天缺陷--因基于面均质量检测的原理,QCM技术对溶液中蛋白的检测下限仅在1μg mL-1数量级.进一步,我们探索了QCM的发展方向和潜在应用领域,希望籍此能进一步推广QCM在各个学科界面问题中的研究应用.

The development of quartz crystal microbalance

Quartz crystal microbalance（QCM）,which is a sensitive and practical tool for measurement of the changes of interface,has got certain applications in the study of interface problems in physical,chemical,biological,pharmaceutical,clinical medicine and environmental science.However,the application and promotion of QCM in liquid phase has been limited by the difficulties of quantitative interpretation of QCM data.To solve this problem,researchers have developed a variety of advanced QCM,such as the QCM with the impedance analysis（impedance QCM,i-QCM） or the QCM that can monitor the energy dissipation（QCM with dissipation,QCM-D）.At the same time,many corresponding theoretical models also have been developed.However,for most biological and chemical researchers,these theories are too complicated,which greatly limits the potential of QCM study.This review classified the reported methods,models and equations of QCM into five categories by application conditions with a clue of our group＇s research work in the QCM and provided a clear definition of criteria：i） solid-gas interface;ii） Newtonian fluid;iii） solid-liquid interface of thin film studies;iv） solid-liquid interface of thick film studies;v） solid-liquid interface of ultra-thick film studies.For each type of situation,we will describe how to simplify the QCM data and ensure the accuracy of quantitative analysis in simple language that chemists and biologist can understand.For QCM data analysis in liquid environment,we emphatically introduce the ＂solidified liquid＂ model,which allows QCM become a molecular ruler under certain conditions with the working range from nanometers to micrometers.The molecular ruler has a good application in some innovative interface researches.Finally,we theoretically analyze the defects of QCM as a biosensor-the sensitivity of protein concentration detection is limited by the ＂detection of surface average mass＂ at only 1 μg mL^-1.Furthermore,we propose the development direction and potential applications of QCM,and hope that QCM can be extended in various problems of the interface application.