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Effect of polymer grafting density on silica nanoparticle toxicity
Link to Journal 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.
For this study, the authors 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, they 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.
Peer Reviewed Journal Article
Exposure Or Hazard Target
Method Of Study
Risk Exposure Group
Bioorganics & Medicinal Chemistry, 20(23): 6862-6869 (December 2012)
Bioorganics & Medicinal Chemistry
Lin IC, Liang M, Liu TY, Jia Z, Monteiro MJ, Toth I
Last updated on December 4, 2012
This work is supported in part by the Nanoscale Science and Engineering Initiative of the National Science Foundation
under NSF Award Number EEC-0118007.
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