Deep tissue localization and sensing using optical microcavity probes

• Published in: Nature communications Vol. 13; no. 1; p. 1269
• Main Authors: Kavčič, Aljaž, Garvas, Maja, Marinčič, Matevž, Unger, Katrin, Coclite, Anna Maria, Majaron, Boris, Humar, Matjaž
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11-03-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1107/510; 639/624/1111/55; 639/624/399/1097; Emission spectra; Emissions; Fluorescence; Humanities and Social Sciences; Line spectra; Localization; Microcavities; Microlasers; multidisciplinary; Optical Imaging; Probes; Scattering; Science; Science (multidisciplinary); Spectral sensitivity; Tissues; Tracking
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28904-6

Optical microcavities and microlasers were recently introduced as probes inside living cells and tissues. Their main advantages are spectrally narrow emission lines and high sensitivity to the environment. Despite numerous novel methods for optical imaging in strongly scattering biological tissues, imaging at single-cell resolution beyond the ballistic light transport regime remains very challenging. Here, we show that optical microcavity probes embedded inside cells enable three-dimensional localization and tracking of individual cells over extended time periods, as well as sensing of their environment, at depths well beyond the light transport length. This is achieved by utilizing unique spectral features of the whispering-gallery modes, which are unaffected by tissue scattering, absorption, and autofluorescence. In addition, microcavities can be functionalized for simultaneous sensing of various parameters, such as temperature or pH value, which extends their versatility beyond the capabilities of standard fluorescent labels.
Optical microcavities are useful as probes in cells due to their narrow emission spectra and high sensitivity to environment. Here, the authors use the unique spectral features of microcavities, which are unaffected by tissue scattering, and show 3D localisation and tracking of cells deep in tissues.