20.500.12556/DiRROS-28312 Nanometer-precision tracking of adipocyte dynamics via single lipid droplet whispering-gallery optical resonances Biophotonics─and more recently, biointegrated photonics─offer transformative tools for probing cellular processes with unprecedented precision. Among these, whispering-gallery-mode (WGM) resonators (optical microcavities formed in spherical structures) have emerged as powerful biosensors and intracellular barcodes. Lipid droplets (LDs), with their high refractive index and intrinsic spherical geometry, are ideal candidates for supporting intracellular lasing. Although lasing in LDs has been previously demonstrated, it has not yet been harnessed to study live-cell biology. Here, we report the first use of WGM resonances in LDs of live primary adipocytes, employing a continuous-wave (CW) laser at powers below the biological damage threshold. By measuring these resonances, we achieved nanometer-scale precision in size estimation, enabling real-time observation of rapid LD dynamics and deformations on the minute scale─far beyond the spatiotemporal resolution of conventional microscopy. We systematically characterized this photonic sensing approach, demonstrating its ability to resolve adipocyte heterogeneity, monitor lipolytic responses to forskolin and isoproterenol, and detect early signs of cell viability loss─well before conventional assays. This proof-of-concept establishes intracellular LD WGM resonances as a robust platform for investigating live single-cell metabolism. The technique enables rapid, cost-effective assessment of adipocyte function, reveals cell-to-cell variability obscured by bulk assays, and lays the foundation for high-throughput analysis of metabolism- and obesity-related diseases at both the cellular and tissue levels. adipocyte dynamics lipid droplets dinamika adipocitov lipidi kapljice true false true ACS Publications ZDA Angleški jezik Slovenski jezik © 2025 The Authors. Neznano 2026-03-13 13:25:45 2026-03-13 13:25:45 2026-03-14 04:25:59 0000-00-00 00:00:00 2026 0 0 Nasl. z nasl. zaslona; Opis vira z dne 13. 3. 2026; Str. 511-521 iss. 1 Vol. 11 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-09-05 2025-12-18 2025-12-29 577 2379-3694 10.1038/s41377-021-00561-2 271613187 https://pubs.acs.org/doi/10.1021/acssensors.5c03272 1 c3e1230c-1ed7-11f1-acf8-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=41805 RAZ_Podlipec_Rok_2026.pdf RAZ_Podlipec_Rok_2026.pdf 1 D133833E700E2323BC86DA2D0BB410DE ac26a86f15dd95fdb7755b428c61f96496bb6412917bca26e9ed4f04bb6906a8 1bd81744-1ed8-11f1-acf8-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=41807 Institut Jožef Stefan 0 0 0