Department of Chemistry, Sogang University, Seoul, 04107, South Korea.
School of Advanced Materials Science and Engineering, Department of MetaBioHealth Sungkyunkwan University (SKKU), Suwon, 16419, South Korea.
Adv Sci (Weinh). 2024 Jul;11(28):e2309702. doi: 10.1002/advs.202309702. Epub 2024 May 5.
This paper presents the first scanning electron microscopy (SEM)-based DNA imaging in biological samples. This novel approach incorporates a metal-free electro-stain reagent, formulated by combining DNA-binding proteins and synthetic polymers to enhance the visibility of 2-nm-thick DNA under SEM. Notably, DNA molecules stain with proteins and polymers appear as dark lines under SEM. The resulting DNA images exhibit a thickness of 15.0±4.0 nm. As SEM is the primary platform, it integrates seamlessly with various chemically functionalized large surfaces with the aid of microfluidic devices. The approach allows high-resolution imaging of various DNA structures including linear, circular, single-stranded DNA and RNA, originating from nuclear and mitochondrial genomes. Furthermore, quantum dots are successfully visualized as bright labels that are sequence-specifically incorporated into DNA molecules, which highlights the potential for SEM-based optical DNA mapping. In conclusion, DNA imaging using SEM with the novel electro-stain offers electron microscopic resolution with the ease of optical microscopy.
本文提出了基于扫描电子显微镜（SEM）的生物样本中 DNA 成像的首例研究。该新方法采用了一种无金属的电染色试剂，由结合 DNA 结合蛋白和合成聚合物的组合而成，可增强 SEM 下 2nm 厚 DNA 的可见度。值得注意的是，带有蛋白和聚合物的 DNA 分子在 SEM 下呈现为暗线。得到的 DNA 图像显示厚度为 15.0±4.0nm。由于 SEM 是主要平台，借助微流控装置，它可与各种经过化学功能化的大型表面无缝集成。该方法可以高分辨率成像各种 DNA 结构，包括来自核和线粒体基因组的线性、圆形、单链 DNA 和 RNA。此外，量子点可作为明亮标记成功可视化，这些标记被特异性地整合到 DNA 分子中，这突显了基于 SEM 的光学 DNA 图谱的潜力。总之，使用新型电染色剂的 SEM 进行 DNA 成像提供了具有光学显微镜易用性的电子显微镜分辨率。
