Figure 4.

Intravital microscopy (IVM) reveals the spatiotemporal localization of CpG-NPs in the TME following MN transdermal delivery, as well as their therapeutic efficiency. A, Experimental design of the in vivo studies. B, IVM of mApple expressing MC38 tumors (yellow) treated with fluorescent CpG-NPs (magenta) loaded in the MNs. MNs were applied to the mApple MC38 tumors for 24 h and removed before IVM imaging. C, Single cell uptake quantification of CpG-NPs by IVM. Data are mean ± s.e.m. D-F, Mice with subcutaneous MC38-mApple tumors were treated seven days post-tumor induction with empty MNs, MNs loaded with CpC_Ctrl-NPs (1 µg CpC-ODN delivered/patch) or MNs loaded with CpG-NPs (1 µg CpG-ODN delivered/patch) three days apart for five cycles (q3dx5), with tumor growth measured by caliper and shown as average volumes (D), individual growth curves (E), and Kaplan-Meier humane survival curves (F) (n = 8-10, data are mean ± s.e.m.). Statistical significance was determined between groups by the Mantel-Cox test. ***P < 0.001, **P < 0.01, *P < 0.05. G, mApple tumor fluorescence over time, measured by IVM (n = 2-5, data are mean ± s.e.m.). H, IVM of MC38-mApple tumors (yellow) treated with fluorescent CpG-NPs (magenta) (left, scale bar: 1 mm; right, scale bar: 100 µm).