(a) Representative time course of in vivo fluorescence imaging of B16F10 melanomas treated with PBS injection, Cy5-CPMV injection, Cy5-CPMV passive MN, or Cy5-CPMV active MN. Colors denote radiant efficiency ((p/sec/cm2/sr)/(μW/cm2)) of Cy5-CPMVfluorescence. (b) Quantification (average radiant efficiency) of Cy5-CPMV fluorescence in tumor ROI in vivo at different timepoints after treatment with PBS (blue circle, n=4), Cy5-CPMV injection (red square, n=5), Cy5-CPMV passive MN (green upward-pointing triangle, n=7), or Cy5-CPMV active MN (purple downward-pointing triangle, n=7). Data are medians ± interquartile range. No significant differences in radiant efficiency was observed in Active MN vs. Passive MN and CPMV vs. Passive MN at any timepoints. Tumor growth was compared on different time points by Kruskal-Wallis one-way ANOVA with Dunn’s multiple comparisons correction: *P<0.05, **P<0.01, ***P<0.001. (c) Immunofluorescence of tumors 24 hours after treatment (blue: nucleus, pink: blood vessels, green: leukocytes, yellow: Cy5-CPMV, arrow: Cy5 CPMV, *: blood vessel, dashed circle: leukocyte). Abbreviations: BL, baseline; p, photon; sr, steradian; W, watt)