Institute of Semiconductor Physics SB RAS, Novosibirsk, Russia.
Anal Chim Acta. 2011 Feb 14;687(1):75-81. doi: 10.1016/j.aca.2010.11.055. Epub 2010 Dec 8.
A new method based on the use of quartz crystal microbalance (QCM) as an active sensing element is developed, optimized and tested in a model system to measure the rupture force and deduce size distribution of nanoparticles. As suggested by model predictions, the QCM is shaped as a strip. The ratio of rupture signals at the second and the third harmonics versus the geometric position of a body on QCM surface is investigated theoretically. Recommendations concerning the use of the method for measuring the nanoparticle size distribution are presented. It is shown experimentally for an ensemble of test particles with a characteristic size within 20-30 nm that the proposed method allows one to determine particle size distribution. On the basis of the position and value of the measured rupture signal, a histogram of particle size distribution and percentage of each size fraction were determined. The main merits of the bond-rupture method are its rapid response, simplicity and the ability to discriminate between specific and non-specific interactions. The method is highly sensitive with respect to mass (the sensitivity is generally dependent on the chemical nature of receptor and analyte and may reach 8×10(-14) g mm(-2)) and applicable to measuring rupture forces either for weak bonds, for example hydrogen bonds, or for strong covalent bonds (10(-11)-10(-9) N). This procedure may become a good alternative for the existing methods, such as AFM or optical methods of determining biological objects, and win a broad range of applications both in laboratory research and in biosensing for various purposes. Possible applications include medicine, diagnostics, environmental or agricultural monitoring.
一种基于石英晶体微天平（QCM）作为活性传感元件的新方法被开发、优化并在模型系统中进行了测试，以测量纳米颗粒的断裂力并推断其尺寸分布。正如模型预测的那样，QCM 被设计成条状。理论上研究了第二和第三谐波的断裂信号与 QCM 表面上物体的几何位置之间的比值。提出了关于该方法用于测量纳米颗粒尺寸分布的建议。实验表明，对于具有 20-30nm 特征尺寸的一组测试粒子，所提出的方法允许确定粒子尺寸分布。基于测量的断裂信号的位置和值，可以确定粒子尺寸分布的直方图和每个尺寸分数的百分比。键断裂方法的主要优点是其快速响应、简单性和区分特异性和非特异性相互作用的能力。该方法对质量非常敏感（灵敏度通常取决于受体和分析物的化学性质，并且可以达到 8×10(-14) g mm(-2)），并且适用于测量弱键（例如氢键）或强共价键（10(-11)-10(-9) N）的断裂力。该方法可能成为现有方法（如 AFM 或光学方法确定生物对象）的良好替代品，并在实验室研究和各种目的的生物传感中获得广泛的应用。可能的应用包括医学、诊断、环境或农业监测。
