Fig. 4

In vivo biodistribution of free DiR-BOA and DiR-BOA-labeled F127, NM@F127 and R4F-NM@F127 in CIA mice. a Real-time fluorescence imaging of CIA mice after intravenous injection with DiR-BOA-labeled F127, NM@F127, and R4F-NM@F127 and free DiR-BOA. b Ex vivo imaging of the organs at 24 h after intravenous injection. c Quantitative analysis of the radiant efficiency in the joints. d Fluorescence imaging of synovial fluid collected from CIA mice injected with DiR-BOA-labeled F127, NM@F127, and R4F-NM@F127 and free DiR-BOA. e Quantitative analysis of the radiant efficiency in the joint synovial fluid. f Quantitative analysis of the MFI of DiR-BOA in synovial fluid macrophages (F4/80⁺CD11b⁺). MFI: mean fluorescence intensity. g Fluorescence images of frozen sections of synovial tissue. Scale bar, 50 μm; Blue, DAPI; Green, Synovial macrophages; Red, DiR-BOA. Data are presented as the mean ± SEM (n = 3) and were statistically analyzed using one-way ANOVA followed by Tukey’s multiple comparisons test by comparing the group marked with * with the free DiR-BOA group. ns represents no significant difference; ***p < 0.001; ^#p < 0.05, and ^###p < 0.001