Nucleic Acid Probes for Single-Molecule Localization Imaging of Cellular Biomolecules

Abstract

Endogenous biomolecules in cells are the basis of all life activities. Directly visualizing the structural characteristics and dynamic behaviors of cellular biomolecules is significant for understanding the molecular mechanisms in various biological processes. Single-molecule localization microscopy (SMLM) can circumvent the optical diffraction limit, achieving analysis of the fine structures and biological processes in living cells with nanoscale resolution. However, the large size of traditional imaging probes prevents SMLM from accurately locating fine structures and densely distributed biomolecules within cells. In recent years, nucleic acid probes have emerged as potential tools to replace conventional SMLM probes by virtue of their small size and high specificity. In addition, due to their programmability, nucleic acid probes with different conformations can be constructed via sequence design, further extending the application of SMLM in bioanalysis. Here, we discuss the design concepts of different conformational nucleic acid probes for SMLM and summarize the application of SMLM based on nucleic acid probes in the field of biomolecules. Furthermore, we provide a summary and future perspectives of the nucleic acid probe-based SMLM technology, aiming to provide guidance for the acquisition of nanoscale information about cellular biological processes.

Chemical Modification and Delivery System of Small Interfering RNA Drugs★

“…通过智能设计和精准调控, 可以开发出具有靶向性、示 踪性和与其他药物共递送性的多功能 siRNA 纳米药物, 以实现协同增效. 这也是未来 siRNA 药物发展的重要方 向之一 [132,[134][135] . 通过持续的研究和创新, 我们可以期 待看到更多智能设计的 siRNA 纳米药物的问世, 为疾病 治疗带来新的突破.…”

Light and endogenous enzyme triggered plasmonic antennas for accurate subcellular molecular imaging with enhanced spatial resolution

“…1,2 In situ imaging of disease-related biomolecules at the subcellular level can provide more effective information such as positioning guidance for accurate and early clinical diagnosis. [3][4][5] In view of this prominent prospect, accurate sensing and imaging of disease-related biomolecules including RNA, 6 ions, 7,8 small molecules 9 and proteins, 10 at the subcellular level has recently attracted considerable attention. Despite these signicant advances achieved, accurate molecular imaging at the subcellular level still severely suffered from two non-negligible shortcomings: (1) most disease-related biomolecules are not only highly expressed in tumor cells, but also have non-negligible expression levels in normal cells, 11,12 and the use of conventional molecular imaging strategies for biomolecule detection in tumor cells at the subcellular level still suffered from low signal-to-background ratios because of the signal responses in normal cells resulting from the "always-active" mode, 13 resulting in "off-tumor" signal leakage and thus reducing the spatial resolution.…”

Enhanced β-Amyloid Aggregation in Living Cells Imaged with Quinolinium-Based Spontaneous Blinking Fluorophores

“…However, due to the small size of Aβ aggregates and the limited spatial resolution of epifluorescence microscopy, determining the early assembly states of Aβ aggregates in living cells remains a great challenge. Single-molecule localization microscopy (SMLM) can obtain nanoscopic images by stochastic and sparse activation of individual fluorophores in successive acquisitions. − It provides a solution to get improved spatial resolution on the dynamic aggregation process. − Organic fluorophores have been widely applied in SMLM due to their small sizes, high photon output, and adjustable blinking properties. − Generally, the blinking behavior of single fluorophore can be modulated by adding additives to the solution, such as redox modulators and exogenous nucleophiles. , However, these additives are potentially toxic to biological system and may disturb cellular metabolism. , Therefore, it is important to develop fluorophores with spontaneous blinking properties for the nanoscopic imaging of intracellular Aβ aggregates.…”