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Although biodegradable amphiphilic block copolymer micelles have been widely applied in the clinical applications as drug delivery nanocarriers, low-efficiency cellular internalization frequently reduces therapeutic efficacy of the loaded drugs. Here, we demonstrate photothermal effect-promoted cellular internalization of finely tuned thermo-responsive amphiphilic biodegradable block copolymer nanocarriers via noninvasive stimuli of near-infrared (NIR) light irradiation. Amphiphilic block copolymers, poly(ε-caprolactone)-block-poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (PCL-b-P(NIPAM-co-DMA)), are prepared with finely tuned compositions of P(NIPAM-co-DMA) for desirable lower critical solution temperature (LCST) of the block copolymer micelles in aqueous solution. The block copolymers are then used to co-encapsulate doxorubicin (DOX) and indocyanine green (ICG), which show high encapsulation efficiency and significant photothermal effect upon exposure to NIR light irradiation. The photothermal effect-induced collapse and hydrophilic-to-hydrophobic transition of P(NIPAM-co-DMA) shells significantly enhance the interactions between drug-loaded micelles and cell membranes, which dramatically promote the cellular internalization of the micelles and therapeutic efficacy of loaded anticancer drugs. |
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Keywords:stimuli-sensitive polymers, drug delivery systems, micelles, block copolymers, photothermal effect |
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