Photo-responsive nitrophenyl moieties were proposed to conjugate as pendants of the pullulan backbone through labile carbamate linkage to yield amphiphilic pullulan derivatives. Note that the hydrophobicity of the conjugated nitrophenyl… Click to show full abstract
Photo-responsive nitrophenyl moieties were proposed to conjugate as pendants of the pullulan backbone through labile carbamate linkage to yield amphiphilic pullulan derivatives. Note that the hydrophobicity of the conjugated nitrophenyl components in the amphiphiles enable facile their self-assembly with the hydrophobic chemotherapeutic drug (doxorubicin) as the internal drug reservoirs, whereas the hydrophilic pullulan segments existed as the biocompatible surroundings. Upon photo-illumination, the carbamate linkage was susceptible to cleavage for departure of the nitrophenyl components from the pullulan backbone owing to the photo-responsive nitrophenyl moieties. Simultaneously, the nitrophenyl components transformed into water-soluble aldehyde-terminalized nitrosophenyl derivatives, leadingly accounting for structural disassembly and liberation of the cytotoxic doxorubicin payloads. Therefore, our proposed photo-responsive strategy could address the reluctant intracellular drug release drawbacks of the conventional amphiphile-based drug delivery systems. Notably, markedly lower IC50 (half maximal inhibitory concentration) index of our constructed doxorubicin delivery systems was determined to be approximately 1.0 μg/mL upon photo-illumination, in contrast to IC50 index of 5.6 μg/mL in the absence of photo-illumination (approximate fivefold), thereby representing as a facile spatiotemporal artifice to execute on-demand drug release to the photo-imposed cells.
               
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