Characterization of physicochemical properties of Ce6-P/W NE nanodroplets. (a) Ultraviolet–visible light absorption spectrum. Ce6 concentration, 12 μg/mL. (b) Hydrodynamic diameter. Ce6 concentration, 16 μg/mL. (c) Physical stability: Plot shows droplets size for different storage periods at 4 °C. Ce6 concentration, 16 μg/mL. (d) Zeta potential. Ce6 concentration, 16 μg/mL. (e) Fluorescence emission spectra of Ce6 dissolved in ethanol and Ce6-P/W NE with the same Ce6 concentration (12 μg/mL). (f) Droplet diameter change of the Ce6-P/W NEs in DMEM cell culture medium supplemented with 10% fetal bovine serum throughout storage at 37 °C for 24 h. Ce6 concentration, 16 μg/mL. All data were presented as mean value ± standard deviation. After Levene’s test for equality of variances, one-way analysis of variance (ANOVA) and Bonferroni multiple comparison test was employed for the comparison of mean values. n = 3. Ce6-P/W NE, chlorin e6-perfluoropolyether (PFPE)/water nanoemulsion.