20.500.12556/DiRROS-31349 Edible optical microcavities for optical barcoding, authentication, and sensing The safety, authenticity, and traceability of food and pharmaceutical products are critical challenges, especially in the context of widespread counterfeiting. Most existing anti-counterfeiting and sensing technologies are applied externally to packaging, making them vulnerable to tampering. A more robust approach is to incorporate them directly into edible products. Whispering-gallery modes (WGMs), highly sensitive optical resonances supported by spherical microcavities, provide a promising platform due to their environmental responsiveness and spectral uniqueness. Here, we demonstrate edible WGM microcavities based on chlorophyll-coated silica microspheres. Monodisperse microspheres exhibit stable WGM resonances under continuous-wave laser excitation, with quality factors ranging from 2,000 to 10,000. Individual microsphere diameters are determined with a precision of approximately 40 nm. When embedded in low-refractive-index agarose matrices, the microspheres generate size-specific spectral signatures that function as optical barcodes and remain stable for at least six months. Based on intrinsic size variations, we further demonstrate edible physical unclonable functions (PUFs) with stable and unique optical identifiers. In addition, the microcavities enable sugar concentration measurements with uncertainties as low as 0.23 percentage points and pH sensing with an accuracy of approximately 0.3 pH units, when embedded in a pH-responsive hydrogel. These results establish edible WGM microcavities as a multifunctional platform for secure labeling, sensing, and anti-counterfeiting in consumable products. edible materials whispering gallery modes optical barcodes physical unclonable functions sensors true false true Nature Publishing Group Združeno kraljestvo Angleški jezik Ni določen © The Author(s) 2026 Neznano 2026-07-29 12:00:22 2026-07-29 12:00:23 2026-07-30 03:49:46 0000-00-00 00:00:00 2026 0 0 Nasl. z nasl. zaslona; Opis vira z dne 24. 7. 2026; str. 1-11 Vol. 16, article no. 21935 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-11-04 2025-04-25 2026-07-14 535 2045-2322 2045-2322 286022147 https://www.nature.com/articles/s41598-026-51128-3 1 53c99afc-8b34-11f1-923b-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=48497 RAZ_Rehman_Anwar_Abdur_2026.pdf RAZ_Rehman_Anwar_Abdur_2026.pdf 1 02F3BBF15C53772E51E5D6C096B867A4 599f64083da2b3189e28e4af11f8fc5f5e9c99933e9c5c2a4519351865a8906f aada72d0-8b34-11f1-923b-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=48498 Institut Jožef Stefan 0 0 0