Super-resolution microscopy, the Nobel Prize–winning innovation that allows imaging below the diffraction limit of light, has enabled some breathtakingly sharp views of tiny biological structures. But it’s not something you’ll find in a typical biology lab—instead, it requires sometimes complex and costly tools and substantial image post-processing.
Now, researchers at the Macquarie University ARC Center of Excellence for Nanoscale BioPhotonics (CNBP), Australia, have developed a scheme that they say could bring 3-D sub-diffraction imaging capability to the standard confocal microscopes that are ubiquitous in bio labs (Nat. Commun., doi: 10.1038/s41467-019-11603-0). The technique—which the team has dubbed upconversion super-linear excitation–emission (uSEE) microscopy—rests on a clever use, as fluorescent markers, of so-called upconversion nanoparticles (UCNPs), which provide sharp, tunable narrow emissions when excited by low-power, near-infrared light.