Back to Journals » International Journal of Nanomedicine » Volume 11

Raspberry-like poly(γ-glutamic acid) hydrogel particles for pH-dependent cell membrane passage and controlled cytosolic delivery of antitumor drugs

Authors Cho SH, Hong JH, Noh YW, Lee E, Lee CS, Lim YT

Received 21 July 2016

Accepted for publication 13 September 2016

Published 27 October 2016 Volume 2016:11 Pages 5621—5632


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Thomas Webster

Sun-Hee Cho,1,* Ji Hyeon Hong,2,* Young-Woock Noh,1 Eunji Lee,2 Chang-Soo Lee,3 Yong Taik Lim1

1SKKU Advanced Institute of Nanotechnology, School of Chemical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do, 2Graduate School of Analytical Science and Technology, Chungnam National University, 3Hazards Monitoring Bionano Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong-gu, Daejeon, Republic of Korea

*These authors contributed equally to this work

Abstract: In this research, we synthesized bioderived poly(amino acid) hydrogel particles that showed pH-dependent membrane-disrupting properties and controlled cytosolic delivery of antitumor drugs. Poly(γ-glutamic acid) (γ-PGA) that has been produced extensively using bacteria, especially those of Bacillus subtilis species, was modified with cholesterol (γ-PGA/Chol), and the γ-PGA/Chol conjugates were used to form polymeric nanoparticles the size of 21.0±1.1 nm in aqueous solution. When the polymeric nanoparticles were mixed with doxorubicin (Dox), raspberry-like hydrogel particles (RBHPs) were formed by the electrostatic interaction between the cationically charged Dox and the anionically charged nanoparticles. The average size and surface charge of the RBHPs in aqueous solution were 444.9±122.5 nm and -56.44 mV, respectively. The loaded amount of Dox was approximately 63.9 µg/mg of RBHPs. The RBHPs showed controlled drug release behavior in both in vitro and ex vivo cell-based experiments. Through fluorescence microscopy and fluorescence-activated cell sorting, the cellular uptake of RBHPs into human cervical cancer cells (HeLa) was analyzed. The cytotoxic effect, evaluated by the methyl tetrazolium salt assay, was dependent on both the concentration of RBHPs and the treatment time. The pH-dependent membrane-disrupting properties of the RBHPs and the subsequent cytosolic delivery of Dox were evaluated using a standard hemolysis assay. Upon an increase in hydrophobicity at the lysosomal acidic pH, RBHPs could easily interact, penetrate cell membranes, and destabilize them. Taken together, the data suggested that RBHPs could be used as drug delivery carriers after loading with other therapeutic drugs, such as proteins or small interfering RNA for cancer therapy.

Keywords: hydrogel particles, controlled release, endosomal escape, antitumor

Creative Commons License This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.

Download Article [PDF]  View Full Text [HTML][Machine readable]