Thermo-triggered Drug Release from Actively Targeting Polymer Micelles

How to deliver the drug to the target area at the right time and at the right concentration is still a challenge in cancer therapy. In this study, we present a facile strategy to control drug release by precisely controlling the thermo-sensitivity of the nanocarriers to the variation of environmental temperature. One type of thermoresponsive Pluronic F127-poly(d,l-lactic acid) (F127-PLA, abbreviated as FP) copolymer micelles was developed and decorated with folate (FA) for active targeting. FP100 micelles assembled from FP with PLA segment having polymerization degree of 100 had a low critical solution temperature of 39.2 °C close to body temperature. At 37 °C, little amount of encapsulated anticancer drug DOX is released from the FP100 micelles, while at a slightly elevated temperature (40 °C), the shrinkage of thermoresponsive segments causes a rapid release of DOX and instantly increases the drug concentration locally. The cytocompatibility analysis and cellular uptake efficiency were characterized wit...