Effect of polymer grafting density on silica nanoparticle toxicity

Lin, I-Chun, Liang, Mingtao, Liu, Tzu-Yu, Jia, Zhongfan, Monteiro, Michael J. and Toth, Istvan (2012) Effect of polymer grafting density on silica nanoparticle toxicity. Bioorganic & Medicinal Chemistry, 20 23: 6862-6869. doi:10.1016/j.bmc.2012.09.045

Author Lin, I-Chun
Liang, Mingtao
Liu, Tzu-Yu
Jia, Zhongfan
Monteiro, Michael J.
Toth, Istvan
Title Effect of polymer grafting density on silica nanoparticle toxicity
Journal name Bioorganic & Medicinal Chemistry   Check publisher's open access policy
ISSN 0968-0896
Publication date 2012-12
Sub-type Article (original research)
DOI 10.1016/j.bmc.2012.09.045
Volume 20
Issue 23
Start page 6862
End page 6869
Total pages 8
Place of publication Kidlington, Oxford, United Kingdom
Publisher Pergamon
Collection year 2013
Language eng
Abstract Nanoparticles are commonly engineered with a layer of polymers on the surface used to increase their stability and biocompatibility, as well as providing multifunctional properties. Formulating the nanoparticle size and surface properties with polymers directly affects the way these nanoparticles interact with a biological system. Many previous studies have emphasized the importance of nanoparticle size and surface charge in affecting their toxicity in cells. However, the potential weakness in many of these studies is that the polymer grafting densities on nanoparticles have been disregarded during toxicity evaluation. In the current study, we hypothesized that the density of polymers on nanoparticles will affect their toxicity to cells, especially for nanoparticle cores that are toxic themselves. To address this issue, we synthesized a range of RAFT (reversible addition fragmentation chain transfer) polymers bearing different surface charges and coated them onto silica nanoparticles (SiNPs) with different grafting densities. The in vitro cytotoxicity of these SiNPs was evaluated using the MTT (thiazolyl blue tetrazolium bromide) assay with Caco-2 cells. We found that neutral (biocompatible) polymers with a high grafting density on SiNPs were effective at protecting the cells from the toxicity of the silica core. High cellular toxicity was only observed for cationic polymer-SiNPs, while all other neutral and anionic polymer-SiNPs induced limited cellular toxicity. In contrast, the toxic effects induced by low density polymer-coated SiNPs were mostly attributed to the silica core, while the polymer coatings had a limited contribution. These findings are important indicators for the future evaluation of the toxicological profile of polymer-coated nanoparticles.
Keyword Silica nanoparticle
RAFT polymer
MIT assay
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online: 28 September 2012.

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