Fig. 5
Intracellular reflectophores. a Time-lapse phase-contrast images of live Hela cells in culture engulfing reflectophores. Arrowheads indicate the reflectophore under endocytosis. The dotted line demarcates the cell’s margin. b Population kinetics of intracellular uptake for surface-functionalized polystyrene reflectophores (d ≈ 3 μm). The number of samples for each group: n = 45 cells for “amine”, n = 66 cells for “biotin”, and n = 50 cells for “none”. The error bar represents standard error of the mean. c A long-term 3D spheroid culture. Hela cells loaded with reflectophores were subsequently cultured over several days to form a tumor spheroid. d Representative spectral measurements on intracellular reflectophores annotated in c. The measured diameters are 3436 nm for “i”, 3212 nm for “ii”, 3029 nm for ‘iii’, and 3006 nm for “iv”. The solid sinusoidal curves are the best-fit simulation spectra (R2: 0.99 for “i”, 0.98 for “ii”, 0.99 for “iii”, and 0.97 for “iv”). e Measurement precision for intracellular reflectophores. Individual intracellular reflectophores annotated in c were traced over 60 min. The measured diameters are 3436 ± 2.6 nm for ‘i’, 3212 ± 3.1 nm for ‘ii’, 3029 ± 2.9 nm for ‘iii’, and 3006 ± 2.6 nm for “iv” in mean ± standard deviation. The dotted lines indicate the means. f Barcoded cell tracking over 12 h with intracellular reflectophores. Grayscale image indicates MitoTracker fluorescence and pseudo-colored traces represent time-series tracking of individual reflectophores over time. g Phasor representation of six representative reflectophores measured at multiple time points. The measured diameters are 3169 ± 0.2 nm for “i”, 3379 ± 1.8 nm for “ii”, 3015 ± 0.2 nm for “iii”, 3165 ± 0.7 nm for “iv”, 3155 ± 2.1 for “v”, and 3147 ± 0.9 nm for “vi” in mean ± standard deviation
