Design and synthesis of novel dual-cyclic RGD peptides for αβ integrin targeting.

The specific binding of RGD cyclic peptide with integrin αβ attracts great research interest for tumor-targeting drug delivery. Herein, we designed and synthesized a series of dual-ring RGD-peptide derivatives as a drug carrier for αβ targeting. Three novel peptides showed excellent cell adhesion inhibition effect, in which, P3 exhibited 7-fold enhancement in IC compared with cyclo(RGDfK). Drug-loaded cytotoxicity experiment and imaging experiment indicated that such dual-cyclic RGD peptides have good tumor targeting effects. This work provides a new strategy for the design of novel RGD peptides.