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Preparation of pH-sensitive amphiphilic block star polymers, their self-assembling characteristics and release behavior on encapsulated molecules


Poly(ethylene glycol) (PEG), a polymer with excellent biocompatibility, was widely used to form nanoparticles for drug delivery applications. In this paper, based on PEG, a series of pH-sensitive amphiphilic block star polymers of poly(ethylene glycol)-block-poly(ethoxy ethyl glycidyl ether) (PEG-b-PEEGE) with different hydrophobic length were synthesized by living anionic ring-opening polymerization method. The products were characterized using 1H NMR and gel permeation chromatography. These copolymers could self-assemble in aqueous solution to form micellar structure with controlled morphologies. Transmission electron microscopy showed that the nanoparticles are spherical or rodlike with different hydrophilic mass fractions. The pH response of polymeric aggregates from PEG-b-PEEGE was detected by fluorescence probe technique at different pH. A pH-dependent release behavior was observed and pH-responsiveness of PEG-b-PEEGE was affected by the hydrophobic block length. These results demonstrated that star-shaped polymers (PEG-b-PEEGE) are attractive candidates as anticancer drug delivery carriers.

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This work was supported by the National Natural Science Foundation of China (No. 21174001) and the “211 Project” of Anhui University (No. J01001319). The authors acknowledge the support from “Institute of High Performance Rubber Materials & Products” (Hefei) and “Collaborative Innovation Center for Petrochemical New Materials (Anqing)”.

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Correspondence to Ming Cao or Xiaoshuang Feng.

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Song, X., Cao, M., Chen, P. et al. Preparation of pH-sensitive amphiphilic block star polymers, their self-assembling characteristics and release behavior on encapsulated molecules. Polym. Bull. 74, 183–194 (2017).

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  • pH-sensitive
  • Block star polymer
  • Anionic ring-opening polymerization (AROP)
  • Self assembly