Colloids and surfaces. B, Biointerfaces

pH-Responsive globular poly(ethylene glycol) for photodynamic tumor therapy.

PMID 27595892


In this study, we report the development of extremely small-sized globular poly(ethylene glycol) (gPEG) that can specifically recognize tumor acidic pH. gPEG coupled with chlorin e6 (Ce6, a photosensitizing drug) and 2,3-dimethylmaleic acid (DMA, as a pH-responsive moiety) (gPEG-Ce6-DMA, particle size: 3-4nm in diameter) was easily dispersed in phosphate buffered saline (PBS) without any of the nanoparticle fabrication steps. We observed that gPEG-Ce6-DMA displayed pH-dependent zeta-potential changes due to coupling (at pH 7.4) or decoupling (at pH 6.8-6.0) of DMA. As a result, the uptake of gPEG-Ce6-DMA was significantly increased in tumors at acidic pH, likely due to the decoupling of DMA (backing cationic primary amines). As a result, the preferential cellular uptake of gPEG-Ce6-DMA at acidic pH allowed for a significant enhancement of in vitro/in vivo photodynamic tumor cell ablation under light illumination.

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