Document Type

Article

Publication Date

3-25-2019

Publication Title

Canadian Journal of Chemistry

Volume

97

Issue

8

First Page

577

Last Page

583

DOI

10.1139/cjc-2019-0008

Keywords

Magnetite nanoparticles, bovine serum albumin, Langmuir isotherm, adsorption kinetics, adsorption thermodynamics

Abstract

Bare, uncoated magnetite nanoparticles, synthesized using an electrochemical surfactant-free synthesis, have highly oxidized surfaces that prevent aggregation. These particles have demonstrated highly intriguing biological activity showing extremely potent antibiotic activity against both gram-positive and gram-negative bacteria with little toxicity to rats. This difference in activity could be ascribed to the nature of the protein corona. In this study the kinetics and thermodynamics of the binding of bovine serum albumin, used as a model serum protein, to these magnetite nanoparticles was analyzed. There is no significant change in particle diameter by dynamic light scattering following adsorption indicating corona formation does not induce aggregation. The maximum adsorption capacity of the particles was determined to be 300 mg of BSA/g of magnetite. The particles are able to adsorb 90% of the BSA at protein concentrations as high as 500 mg/L. The adsorption is best described using a pseudo-second-order model and a Langmuir Type III isotherm model. Thermodynamic analysis showed that the process is entropically driven and is spontaneous at all tested temperatures and conditions. However, it appears to be a weak to moderate physical adsorption. This moderate binding affinity could indicate the differential biological activity of these particles towards bacteria and mammalian cells and further support the contention that these are potentially useful new tools for targeting antibiotic-resistant bacteria.

Funding Reference Number

NSERC, 2018-06338

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