MINSTED nanoscopy enters the Ångstrom localization range

Super-resolution techniques have achieved localization precisions in the nanometer regime. Here we report all-optical, room temperature localization of fluorophores with precision in the angstrom ngstrom range. We built on the concept of MINSTED nanoscopy where precision is increased by encircling the fluorophore with the low-intensity central region of a stimulated emission depletion (STED) donut beam while constantly increasing the absolute donut power. By blue-shifting the STED beam and separating fluorophores by on/off switching, individual fluorophores bound to a DNA strand are localized with sigma = 4.7 angstrom, corresponding to a fraction of the fluorophore size, with only 2,000 detected photons. MINSTED fluorescence nanoscopy with single-digit nanometer resolution is exemplified by imaging nuclear pore complexes and the distribution of nuclear lamin in mammalian cells labeled by transient DNA hybridization. Because our experiments yield a localization precision sigma = 2.3 angstrom, estimated for 10,000 detected photons, we anticipate that MINSTED will open up new areas of application in the study of macromolecular complexes in cells. Sub-nanometer localization precision is achieved with all-optical microscopy.

Automated summary

This study demonstrates all-optical, room temperature localization of fluorophores with sub-angstrom precision. By utilizing the concept of MINSTED nanoscopy, the researchers successfully localized individual fluorophores bound to DNA strands by increasing the power of a STED donut beam and using on/off switching. This research opens up new areas of application in studying macromolecular complexes in cells.