Stimulated-emission depletion (STED) microscopy has profoundly extended our horizons to the subcellular level1,2,3. However, it remains challenging to perform hours-long, autofluorescence-free super-resolution imaging in near-infrared (NIR) optical windows under facile continuous-wave laser depletion at low power4,5. Here we report downshifting lanthanide nanoparticles that enable background-suppressed STED imaging in all-NIR spectral bands (λexcitation = 808 nm, λdepletion = 1,064 nm and λemission = 850–900 nm), with a lateral resolution of below 20 nm and zero photobleaching. With a quasi-four-level configuration and long-lived (τ > 100 μs) metastable states, these nanoparticles support near-unity (98.8%) luminescence suppression under 19 kW cm−2 saturation intensity. The all-NIR regime enables high-contrast deep-tissue (~50 μm) imaging with approximately 70 nm spatial resolution. These lanthanide nanoprobes promise to expand the application realm of STED microscopy and pave the way towards high-resolution time-lapse investigations of cellular processes at superior spatial and temporal dimensions.
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This work is supported by the National Key R&D Program of China (no. 2018YFA0902600 and no. 2018YFB1107200), the National Natural Science Foundation of China (21635002, 21771135, 21871071 and 61975123), the Ministry of Education, Singapore (MOE2017-T2-2-110), the Agency for Science, Technology and Research (A*STAR) (grant no. A1883c0011 and no. A1983c0038), National Research Foundation, the Prime Minister’s Office of Singapore under its NRF Investigatorship Programme (award no. NRF-NRFI05-2019-0003), the National Basic Research Program of China (973 Program, grant no. 2015CB932200), Zhangjiang National Innovation Demonstration Zone (ZJ-2019-ZD-005) and the Guangdong Provincial Innovation and Entrepreneurship Project (grant no. 2016ZT06D081). We thank X. Zhao, J. Chen and Z. Mu for technical assistance with the TEM imaging and NIR spectral measurements. We also thank J. Hong for absorption spectra measurements.
The authors declare no competing interests.
Peer review information Nature Nanotechnology thanks the anonymous reviewers for their contribution to the peer review of this work.
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Liang, L., Feng, Z., Zhang, Q. et al. Continuous-wave near-infrared stimulated-emission depletion microscopy using downshifting lanthanide nanoparticles. Nat. Nanotechnol. 16, 975–980 (2021). https://doi.org/10.1038/s41565-021-00927-y