Diffraction barrier broken: Superresolution microscopy with a single laser
A team from MIT and Harvard University has jointly developed a super-resolution imaging platform - Upconversion Random Optical Reconstruction Microscope (U-STORM). This technology utilizes upconversion nanoparticles (UCNPs) that can spontaneously and indefinitely flicker, achieving sub atomic level accuracy in observing molecular structures. The imaging clarity is improved by about a thousand times compared to traditional dye methods, while significantly simplifying the operation process.
Previous work considered upconverting nanoparticles to be completely photostable and non-blinking. Localization-based superresolution microscopy techniques (including stochastic optical reconstruction microscopy [STORM]) rely entirely on the stochastic blinking of light emitters to distinguish closely packed molecules, meaning UCNPs were historically deemed unsuitable for this type of imaging.
“Our work began with a question: Can we develop a superresolution imaging platform that is simultaneously long-term, multicolor, simple to operate, and capable of achieving extremely high localization precision without using imaging buffers or additional optical control?” said Sam Peng, the Pfizer Inc. — Gerald Laubach Career Development Assistant Professor of Chemistry at MIT and a core institute member of the Broad Institute of MIT and Harvard. Researchers in Peng's lab led the work.
"Single-molecule localization microscopy enables high-resolution biological imaging, but its precision is limited by the rapid photobleaching of conventional fluorophores. [At the same time,] multicolor imaging is further constrained by the need for spectrally distinct dyes requiring separate excitations or sequential acquisition," the researchers said, in a paper describing the advancement (see below).
MIT researchers developed a groundbreaking super-resolution imaging platform called upconversion-enabled stochastic optical reconstruction microscopy (U-STORM). The system can operate with just one near-infrared laser. This results in a drastic reduction of an experiment’s complexity.
The MIT and Broad Institute team learned that the ~10-nm core-shell particles used in the current work could be coaxed into spontaneous blinking under continuous near-infrared excitation. The blinking behavior continues indefinitely without the need for complex imaging buffers, oxygen scavengers, or external optical modulation.
Source: photonics
