Targeting peptide iRGD-conjugated amphiphilic chitosan-co-PLA/DPPE drug delivery system for enhanced tumor therapy.

In this paper, we report a novel targeting drug delivery system, obtained using an amphiphilic chitosan-co-(d,l-lactide)/1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine copolymer (CS-co-PLA/DPPE) with the modification of an iRGD (CRGDKGPDC) peptide as the targeting module. Hydrophilic doxorubicin (DOX) was encapsulated and cell experiments were carried out to evaluate the anti-tumor efficacy of DOX-loaded nanoparticles (NPs) in vitro. Characterization data showed a favorable size distribution, high encapsulation efficiency and a pH-dependent release profile for the synthesized NPs. A cytotoxicity assay revealed the higher inhibitory effect of DOX-iRGD-NPs especially in cell lines with an abundant expression of αvβ3 integrin receptors. An increased cellular uptake of DOX-iRGD-NPs was observed and further confirmed to be a consequence of a specific endocytosis pathway mediated by ligand-receptor interactions. Visualization of the intracellular trafficking showed different distributions of DOX when delivered using DOX-NPs and DOX-iRGD-NPs, proving the targeting effect of iRGD. With the help of the iRGD targeting peptide, a chemotherapeutic drug can be delivered specifically to the cancer and endothelial cells expressing αvβ3 integrin receptors to achieve an enhanced anti-tumor efficacy and controlled drug release.