Polymersome-mediated delivery of (R)-roscovitine into the zebrafish tail speeds up inflammation resolution. Zebrafish embryos (mpx:GFP) 3 dpf were subject to tail injury by transection of the tail end. (A) At 4 hpi zebrafish embryos were incubated with polymersomes encapsulating rhodamine B octadecyl ester perchlorate (CelLuminate) for 8 h before the fish were washed and imaged by confocal microscopy. Original magnification ×10. (B) Zebrafish embryos were treated with 30 μM free or encapsulated (R)-roscovitine at 4 hpi. At 12 hpi neutrophils numbers at the injury site were counted using a dissecting microscope. Encapsulated (R)-roscovitine significantly improved inflammation resolution compared with free roscovitine or controls (one-way ANOVA with Bonferroni post hoc comparison, lines represent the mean ± SEM from three independent experiments, ***p < 0.001, ****p < 0.0001).