Biodesign Center for Bioelectronics and Biosensors , Arizona State University , Tempe , Arizona 85287 , United States.
School of Molecular Sciences , Arizona State University , Tempe , Arizona 85287 , United States.
Anal Chem. 2019 Nov 5;91(21):14149-14156. doi: 10.1021/acs.analchem.9b04195. Epub 2019 Oct 17.
Measuring ligand-protein interactions is critical for unveiling molecular-scale biological processes in living systems and for screening drugs. Various detection technologies have been developed, but quantifying the binding kinetics of small molecules to the proteins remains challenging because the sensitivities of the mainstream technologies decrease with the size of the ligand. Here, we report a method to measure and quantify the binding kinetics of both large and small molecules with self-assembled nano-oscillators, each consisting of a nanoparticle tethered to a surface via long polymer molecules. By applying an oscillating electric field normal to the surface, the nanoparticle oscillates, and the oscillation amplitude is proportional to the number of charges on the nano-oscillator. Upon the binding of ligands onto the nano-oscillator, the oscillation amplitude will change. Using a plasmonic imaging approach, the oscillation amplitude is measured with subnanometer precision, allowing us to accurately quantify the binding kinetics of ligands, including small molecules, to their protein receptors. This work demonstrates the capability of nano-oscillators as an useful tool for measuring the binding kinetics of both large and small molecules.
测量配体-蛋白相互作用对于揭示活系统中的分子尺度生物过程以及筛选药物至关重要。已经开发了各种检测技术，但定量小分子与蛋白质的结合动力学仍然具有挑战性，因为主流技术的灵敏度随配体的大小而降低。在这里，我们报告了一种使用自组装纳米振荡器测量和定量大分子和小分子结合动力学的方法，每个纳米振荡器由通过长聚合物分子与表面连接的纳米颗粒组成。通过施加垂直于表面的振荡电场，纳米颗粒会振荡，并且振荡幅度与纳米振荡器上的电荷量成正比。在配体结合到纳米振荡器上之后，振荡幅度将会发生变化。使用等离子体成像方法，可以以亚纳米的精度测量振荡幅度，从而能够准确地定量配体（包括小分子）与其蛋白质受体的结合动力学。这项工作证明了纳米振荡器作为测量大分子和小分子结合动力学的有用工具的能力。
