液体环境单分子免疫球蛋白G的原子力显微镜高分辨成像

原子力显微镜技术( AFM)具有纳米级高分辨成像能力，是研究生物大分子结构和功能的重要工具之一。制备合适的样品是获取高分辨成像的关键要素。本研究结合DNA折纸技术，将抗原分子修饰在DNA折纸上，通过分子识别作用，抗体分子与抗原分子特异性结合，形成由DNA折纸和抗原抗体复合物构成的纳米结构。利用DNA折纸在云母表面上的吸附特点，使得抗体分子选择性地吸附在衬底表面上，由此获得了液体环境中的单个地高辛抗体免疫球蛋白G( IgG)分子的“Y”超微结构形貌。本方法简单、方便，为AFM在单分子水平上检测和表征生物分子结构和功能提供帮助。

High-Resolution Imaging of Single-Molecule Immunoglobulin G Antibodies with Atomic Force Microscopy in Liquid

Atomic force microscopy ( AFM) is one of important tools for studying the structure and function of biomolecules due to its nanoscale capability. A well prepared sample was the primary key issue for high-resolution imaging macromolecules. Here, by using self-assembly technology of DNA origami, antigens were modified on DNA origami. Afterward, antibodies reacted specifically with antigens by a molecular recognition way. Then, a nanostructure formed from DNA origami and antigen-antibody complexes. By the aid of adsorption character of DNA origami, individual antibodies could selectively adsorb on mica surface. As a result, the ultrastructural morphology image of a single IgG molecule, the characteristic“Y-shaped” domains, was resolved in liquid. The way for adsorbing biomolecules on the mica surface in a liquid environment was simple and convenient, and it may be useful to detect and measure biomoleculers at the singe-molecule level with AFM.