CGKRK peptide has high binding affinity for angiogenic blood vessels in orthotopic GBM models. (A) Treatment scheme of mice bearing NSCG-GBMs or NFpp10-GBMs with peptide-tagged micelles. (B) Immunohistochemical analysis of NSCG-GBM after micelle injection. FAM-labelled micelles were injected without peptide (control, Ctrl) or tagged with RGR-FAM, CGKRK-FAM or NGR-FAM peptides (green), and peptide-covered (yellow) CD31+ (red) tumour vessels were quantified; n=2, 200–400 blood vessels/mouse, ***p < 0.0001. (C) Quantitative analysis of peptide-loaded micelles in relation to blood vessels in NFpp10-GBM as in (B); n=2 mice/group, 200–400 blood vessels/mouse. *p =0.022, ***p < 0.0001, ANOVA. Arrows point to some blood vessels with bound peptides. (D) Representative images of FAM-peptide homing to normal brain (control). Scale bars: 50 μm. i.v., intravenous.