Near-Field Nanoscopic Terahertz Imaging of Single Proteins.

Zhongbo Yang, Dongyun Tang, Jiao Hu, Mingjie Tang, Mingkun Zhang, Hong-Liang Cui, Lihua Wang, Chao Chang, Chunhai Fan, Jiang Li, Huabin Wang

Small (Weinheim an der Bergstrasse, Germany) 2021 Jan

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Terahertz (THz) biological imaging has attracted intense attention due to its capability of acquiring physicochemical information in a label-free, noninvasive, and nonionizing manner. However, extending THz imaging to the single-molecule level remains a challenge, partly due to the weak THz reflectivity of biomolecules with low dielectric constants. Here, the development of graphene-mediated THz scattering-type scanning near-field optical microscope for direct imaging of single proteins is reported. Importantly, it is found that a graphene substrate with high THz reflectivity and atomic flatness can provide high THz contrast against the protein molecules. In addition, a platinum probe with an optimized shaft length is found enabling the enhancement of the amplitude of the scattered THz near-field signals. By coupling these effects, the topographical and THz scattering images of individual immunoglobulin G (IgG) and ferritin molecules with the size of a few nanometers are obtained, simultaneously. The demonstrated strategy thus opens new routes to imaging single biomolecules with THz. © 2020 Wiley-VCH GmbH.

Citation

Zhongbo Yang, Dongyun Tang, Jiao Hu, Mingjie Tang, Mingkun Zhang, Hong-Liang Cui, Lihua Wang, Chao Chang, Chunhai Fan, Jiang Li, Huabin Wang. Near-Field Nanoscopic Terahertz Imaging of Single Proteins. Small (Weinheim an der Bergstrasse, Germany). 2021 Jan;17(3):e2005814