Fig. 8: Intracellular microcavities used for tagging and intracellular sensing of relevant parameters in HeLa cells.
From: Review of biosensing with whispering-gallery mode lasers
a Bright-field image of a HeLa cell after internalisation of a polystyrene fluorescent bead. b Processed image of the cell in (a), where the false-colour intensity corresponds to the oscillating WGMs. c Calculated single-bead diameter map from confocal hyperspectral images corresponding to WGM output. d, e Images of bead-containing HeLa cells (d), and corresponding bead diameter map (e). f Time evolution of the resonant peak position for a bead inside a HeLa cell upon the addition of sodium chloride at t = 0; such exposure to a hypertonic solution produces cell volume shrinkage, which in turn causes the concentrations in the cytoplasm to vary, affecting the refractive index, which produces a shift in the peak wavelength. Scale bars 10 μm. Reproduced from ref. 8
