Self-assembled pH-sensitive cholesteryl pullulan nanogel as a protein delivery vehicle

Nobuyuki Morimoto, Sayaka Hirano, Haruko Takahashi, Scott Loethen, David H. Thompson, Kazunari Akiyoshi

Research output: Contribution to journalArticlepeer-review

108 Citations (Scopus)


A self-assembled nanogel, derived from an acid-labile cholesteryl-modified pullulan (acL-CHP), was prepared by grafting vinyl ether-cholesterol substituents onto a 100 kD pullulan main chain polymer backbone. Stable nanogels are formed by acL-CHP self-assemblies at neutral pH. The hydrodynamic radius of the nanogels, observed to be 26.5 ± 5.1 nm at pH 7.0, increased by ∼135% upon acidification of the solution to pH 4.0. SEC analysis of the acL-CHP nanogel at pH 4.0 showed that the grafts were nearly 80% degraded after 24 h, whereas little or no degradation was observed over the same time period for a pH stable analog (acS-CHP) at pH 4.0 or the acL-CHP at pH 7.0. Complexation of BSA with the acL-CHP nanogel was observed at pH 7.0 with subsequent release of the protein upon acidification. These findings suggest that stimuli-responsive, self-assembled nanogels can release protein cargo in a manner that is controlled by the degradation rate of the cholesterol-pullulan grafting moiety.

Original languageEnglish
Pages (from-to)56-63
Number of pages8
Issue number1
Publication statusPublished - 2013 Jan 14

ASJC Scopus subject areas

  • Bioengineering
  • Biomaterials
  • Polymers and Plastics
  • Materials Chemistry


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