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Issue 70, 2016, Issue in Progress
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Quaternized N-chloramine coated magnetic nanoparticles: a trifecta of superior antibacterial activity, minimal residual toxicity and rapid site removal

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Abstract

We propose a new and highly effective tool to add to the ever shrinking toolbox for combating infections caused by antibiotic resistant bacteria; N-chloramine and quaternized N-chloramine were coated onto iron-oxide magnetic nanoparticles to generate antibacterial MNPs. Two differently-sized primary iron-oxide nanoparticles (3 nm and 10 nm) were synthesized and coated with silica and (3-chloropropyl)triethoxysilane, allowing subsequent introduction of N-chloramine precursors – dimethyl hydantoin (DMH) and quaternized dimethyl hydantoin (QDMH). The functionalized MNPs (MNP@DMH and MNP@QDMH) have a clear core–shell structure as evidenced by TEM images. Fe3O4 was identified (by combining X-ray diffraction with Mössbauer spectroscopy) to be the iron oxide in the 10 nm MNPs, while γ-Fe2O3 and Fe3O4 were the 3 nm MNP's oxide phases. Both MNPs (3 nm and 10 nm) have good magnetic responses, with saturation magnetizations of 40 ± 4 emu g−1 and 65 ± 2 emu g−1, respectively. Chlorination activated the antibacterial function and yielded two antibacterial MNPs: MNP@DMCl and MNP@QASCl. At the equivalent [Cl+] of 50 ppm, both coatings demonstrated fast inactivation of the model bacteria methicilin-resistant Staphylococcus aureus (MRSA) and multi-drug resistant (MDR) Pseudomonas aeruginosa. For either size of primary MNPs, MNP@QDMCl is more effective than MNP@DMCl. A hand-held magnet could quickly remove >99% of the functionalized MNPs from a wound simulant within 2 minutes.

Graphical abstract: Quaternized N-chloramine coated magnetic nanoparticles: a trifecta of superior antibacterial activity, minimal residual toxicity and rapid site removal

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Publication details

The article was received on 23 May 2016, accepted on 05 Jul 2016 and first published on 05 Jul 2016


Article type: Paper
DOI: 10.1039/C6RA13389D
RSC Adv., 2016,6, 65837-65846

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    Quaternized N-chloramine coated magnetic nanoparticles: a trifecta of superior antibacterial activity, minimal residual toxicity and rapid site removal

    H. Rahma, R. Nickel, E. Skoropata, Y. Wroczynskyj, C. Rutley, P. K. Manna, C. H. Hsiao, H. Ouyang, J. van Lierop and S. Liu, RSC Adv., 2016, 6, 65837
    DOI: 10.1039/C6RA13389D

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