Ceragenin mediated selectivity of antimicrobial silver nanoparticles

Mark A. Hoppens, Christopher B. Sylvester, Ammar T. Qureshi, Thomas Scherr, Desiree R. Czapski, Randolph S. Duran, Paul B. Savage, Daniel Hayes

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Abstract

The understanding that common broad-spectrum antimicrobials disrupt natural microbial flora important in acquiring nutrients and preventing infection has resulted in a paradigm shift favoring more selective antimicrobials. This work explores silver nanoparticles conjugated with ceragenin, or cationic antimicrobials (CSA-SNPs), as a potential Gram-positive selective antimicrobial. Herein, CSA-SNPs are characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, and high-performance liquid chromatography-electrospray time-of-flight mass spectrometry (HPLC-ESI-TOF-MS). The antimicrobial properties are determined through minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) and time-kill studies. Spatial selectivity of the conjugate nanoparticle was evaluated using confocal imaging, MATLAB statistical analysis, and video monitored interactions between bacteria and CSA-SNPs via laser trapping techniques. Cytotoxicity was also determined by live/dead staining and flow cytometry. Average particle size, as determined through TEM analysis, and hydrodynamic diameter, as determined via DLS, are 63.5 ± 38.8 and 102.23 ± 2.3 nm, respectively. The zeta potential of the SNP before and after CSA attachment is -18.23 and -8.34 mV, respectively. MIC/MBC data suggest that CSA-SNPs are 8 times more effective against Staphylococcus aureus than SNPs alone. Furthermore, MATLAB analysis of confocal imaging found that 70% of CSA-SNPs are within 2 μm of S. aureus, whereas this percentage falls to below 40% with respect to Escherichia coli. These results are bolstered further by laser trapping experiments demonstrating selective adherence of CSA-SNPs conjugates with bacterial strains. Cytotoxicity studies of CSA-SNPs against 3T3 fibroblasts indicate 50% cell viability at 50 ppm.

Original languageEnglish (US)
Pages (from-to)13900-13908
Number of pages9
JournalACS Applied Materials and Interfaces
Volume6
Issue number16
DOIs
StatePublished - Jan 1 2014

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Hoppens, M. A., Sylvester, C. B., Qureshi, A. T., Scherr, T., Czapski, D. R., Duran, R. S., Savage, P. B., & Hayes, D. (2014). Ceragenin mediated selectivity of antimicrobial silver nanoparticles. ACS Applied Materials and Interfaces, 6(16), 13900-13908. https://doi.org/10.1021/am504640f