pH-responsive polymer-liposomes for intracellular drug delivery and tumor extracellular matrix switched-on targeted cancer therapy.

This study presents a tumor-extracellular matrix pH-induced targeting liposome (ECM-targeting liposomes), crosslinked from methoxy-poly(ethylene glycol)-b-poly(N-2-hydroxypropyl methacrylamide-co-histidine)-cholesterol copolymers and biotin2-polyethylene glycol crosslinkers by hydrogen bonds to overcome the defects of liposomes. In this study, ECM-targeting liposomes were completely investigated their pH-responsibility, drug releasing behaviors, anticancer efficiencies and the time-dependent organ distribution and toxic effects. Experimental results indicate that ECM-targeting liposomes showed rapid drug releasing profiles in acidic conditions. Because the ECM-targeting liposomes accumulated preferentially in tumor, the ECM-targeting liposomes exhibited exceptional anticancer activity in vivo and lower hepatic and renal toxicity. The ECM-targeting liposomes which are switched on the targeting ability in tumor ECM possess potential for future application in anticancer therapy.