Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
J Phys Chem A. 2011 Apr 28;115(16):3657-64. doi: 10.1021/jp1031493. Epub 2010 Aug 26.
Aptamer and antibody mediated adhesion is central to biological function and is valuable in the engineering of "lab on a chip" devices. Single molecule force spectroscopy using optical tweezers enables direct nonequilibrium measurement of these noncovalent interactions for three peptide aptamers selected for glass, polystyrene, and carbon nanotubes. A comprehensive examination of the strong attachment between antifluorescein 4-4-20 and fluorescein was also carried out using the same assay. Bond lifetime, barrier width, and free energy of activation are extracted from unbinding histogram data using three single molecule pulling models. The evaluated aptamers appear to adhere stronger than the fluorescein antibody under no- and low-load conditions, yet weaker than antibodies at loads above ∼25 pN. Comparison to force spectroscopy data of other biological linkages shows the diversity of load dependent binding and provides insight into linkages used in biological processes and those designed for engineered systems.
适体和抗体介导的黏附是生物功能的核心，在“片上实验室”设备的工程中具有重要价值。使用光学镊子的单分子力谱学可直接对为玻璃、聚苯乙烯和碳纳米管选择的三个肽适体进行非平衡测量。同样的检测方法也对荧光素标记的抗荧光素 4-4-20 与荧光素之间的强附着进行了全面检查。通过三个单分子拉伸模型，从解附列线图数据中提取键寿命、势垒宽度和活化自由能。在无负载和低负载条件下，评估的适体似乎比荧光素抗体具有更强的黏附力，但在负载超过约 25 pN 时比抗体弱。与其他生物键的力谱数据进行比较表明，负载依赖性结合具有多样性，并为生物过程中使用的键以及为工程系统设计的键提供了深入的了解。
