Antibacterial Activity of Polymer Coated Cerium Oxide Nanoparticles

Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO4, CaCl2, KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to understand the collective influence of the tested parameters on the anti-bacterial activity and subsequently a computer-based, interactive visualization tool was developed. The visualization allows us to elucidate the effect of each of the parameters in combination with other parameters, on the antibacterial activity of nanoparticles. The results indicate that the toxicity of CeO2 NPs depend on the physical and chemical environment; and in a majority of the possible combinations of the nine parameters, non-lethal to the bacteria. In fact, the cerium oxide nanoparticles can decrease the anti-bacterial activity exerted by magnesium and potassium salts

Antibacterial Activity of Polymer Coated Cerium Oxide Nanoparticles

Cerium oxide nanoparticles have found numerous applications in the biomedical industry due to their strong antioxidant properties. In the current study, we report the influence of nine different physical and chemical parameters: pH, aeration and, concentrations of MgSO4, CaCl2, KCl, natural organic matter, fructose, nanoparticles and Escherichia coli, on the antibacterial activity of dextran coated cerium oxide nanoparticles. A least-squares quadratic regression model was developed to understand the collective influence of the tested parameters on the anti-bacterial activity and subsequently a computer-based, interactive visualization tool was developed. The visualization allows us to elucidate the effect of each of the parameters in combination with other parameters, on the antibacterial activity of nanoparticles. The results indicate that the toxicity of CeO2 NPs depend on the physical and chemical environment; and in a majority of the possible combinations of the nine parameters, non-lethal to the bacteria. In fact, the cerium oxide nanoparticles can decrease the anti-bacterial activity exerted by magnesium and potassium salts

Dot plot showing the distribution of residuals for the regression model described in <b>Table 2</b>.

<p>Dot plot showing the distribution of residuals for the regression model described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0047827#pone-0047827-t002" target="_blank"><b>Table 2</b></a>.</p

Design of experiment for understanding the toxicity of dextran-cerium oxide nanoparticles on <i>E. coli</i> and the observed toxicity in each condition.

<p>Design of experiment for understanding the toxicity of dextran-cerium oxide nanoparticles on <i>E. coli</i> and the observed toxicity in each condition.</p

Antibacterial activity of 4.3 ppm cerium oxide nanoparticle complexed with dextran, dextran alone in comparison to control in sterile distilled water.

<p>Antibacterial activity of 4.3 ppm cerium oxide nanoparticle complexed with dextran, dextran alone in comparison to control in sterile distilled water.</p

TEM images of cerium oxide complexed with dextran revealing the size of NPs to be 8–10 nm (a) High resolution TEM image showing the crystallite size of 2–4 nm (b).

<p>TEM images of cerium oxide complexed with dextran revealing the size of NPs to be 8–10 nm (a) High resolution TEM image showing the crystallite size of 2–4 nm (b).</p

Regression coefficients of independent variables obtained by analyzing the data described in Table 1.

<p>Regression coefficients of independent variables obtained by analyzing the data described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0047827#pone-0047827-t001" target="_blank">Table 1</a>.</p

Screen shot of the visualization application showing the anti-bacterial activity of CeO₂ NPs at a) pH 6 and b) pH 8.

<p>The concentration of cations and NOM is set to 0, NPs and <i>E. coli</i> are at 4.3 ppm and 4.63×10⁵ CFU/mL respectively whereas RPM and fructose are set at 200 RPM and 50 ppm respectively.</p

Screen shot of the visualization application showing the effect of potassium salts on the anti-bacterial activity of CeO₂ NPs at a) pH 8, 0 ppm nanoparticle concentration, b) pH 8, 4.3 ppm nanoparticle concentration.

<p>The concentrations of MgSO₄, CaCl₂ and NOM is set to 0, KCl and <i>E. coli</i> are at 15 ppm and 2.34×10⁷ CFU/mL respectively whereas RPM and fructose are set at 200 RPM and 50 ppm respectively.</p