Figure 5.

In vitro PDT efficacy of UCNPs‐Ce6 clusters. a) Dark toxicity assay was performed for 2 h on MB49 monolayer. See Table S2, Supporting Information for respective cluster concentrations. b) In vitro visible light PDT efficacy of UCNPs‐Ce6 clusters formulations in MB49 monolayer cell line. Red # denotes significance compared to single, small, and big groups, and black #, * denotes significance compared to small and big group. Treatment with UCNPs‐Ce6 formulations for 2 h was done, followed by irradiation with a dual‐LED device (405 and 660 nm) for 30 min. c) In vitro NIR PDT efficacy with small UCNPs‐Ce6 clusters on MB49 cell line. d) In vitro NIR PDT efficacy with small UCNPs‐Ce6 clusters on MB49 spheroids. MB49 monolayer cells or 3D spheroids were treated with small UCNPs‐Ce6 clusters at various concentrations for 2 h, followed by irradiation with 980 nm continuous wave laser (2.5 W cm⁻²) for 30 min. Data were represented as mean ± SD. The experiment was performed thrice in duplicates (n = 6) for visible light PDT and twice in duplicates (n = 4) for NIR PDT. #p < 0.05, *p < 0.005. One‐way ANOVA with a Bonferroni post‐hoc analysis was used for comparison among multiple groups.