Chlorotoxin-derived bicyclic peptides for targeted imaging of glioblastomas.

A convenient and efficient strategy was developed for accessing chlorotoxin-derived bicyclic peptide-biomolecule conjugates by cyclizing fully-unprotected linear peptides with a designed tetrafunctional chemical linker. Among these peptides, bicycle-P3 bearing the N-terminal sequence of chlorotoxin shows high tumor selectivity and penetration ability, which is promising for treatment of gliomas.