Responsive Carbonized Polymer Dots for Optical Super-resolution and Fluorescence Lifetime Imaging of Nucleic Acids in Living Cells

• Published in: ACS applied materials & interfaces 2021-11, Vol.13 (43), p.50733-50743
• Main Authors: Liu, Yanfeng, Song, Yiwan, Zhang, Jia, Yang, Zhigang, Peng, Xiao, Yan, Wei, Qu, Junle
• Format: Article
• Language: English
• Subjects: Biological and Medical Applications of Materials and Interfaces; Carbon - chemistry; Cell Line, Tumor; DNA - analysis; Humans; Molecular Structure; Optical Imaging; Polymers - chemical synthesis; Polymers - chemistry; Quantum Dots - chemistry; RNA - analysis
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c13943

The rapid development of advanced optical imaging methods including stimulated emission depletion (STED) and fluorescence lifetime imaging microscopy (FLIM) has provided powerful tools for real-time observation of submicrometer biotargets to achieve unprecedented spatial and temporal resolutions. However, the practical imaging qualities are often limited by the performance of fluorescent probes, leading to unsatisfactory results. In particular, long-term imaging of nucleic acids in living cells with STED and FLIM remained desirable yet challenging due to the lack of competent probes combining targeting specificity, biocompatibility, low power requirement, and photostability. In this work, we rationally designed and synthesized a nanosized carbonized polymer dot (CPD) material, CPDs-3, with highly efficient and photostable emission for the super-resolution and fluorescence lifetime imaging of nucleic acids in living cells. The as-fabricated nanoprobe showed responsive emission properties upon binding with nucleic acids, providing an excellent signal-to-noise ratio in both spatial and temporal dimensions. Moreover, the characteristic saturation intensity value of CPDs-3 was as low as 0.68 mW (0.23 MW/cm2), allowing the direct observation of chromatin structures with subdiffraction resolution (90 nm) at very low excitation (