Issue 1, 2020

Enhanced bactericidal activity of brucite through partial copper substitution

Abstract

Brucite Mg(OH)2 belongs to a family of two-dimensional compounds with a CdI2-type structure built up from layers of edge-sharing octahedra delineating 2D galleries. In the current study, nanometer-sized platelets of copper substituted Mg(OH)2 were prepared by co-precipitation at room temperature in mixed alkaline (NaOH/Na2CO3) medium. Very weak substitution of a few hydroxyl ions by carbonate groups was highlighted at first by infrared spectroscopy and then quantified by thermogravimetric (TG) and mass spectrometric (MS) evolved gas analyses. The presence in a very low amount of water molecules in the galleries induces disorder in the stacking of layers of edge-sharing octahedra along the c-axis. The dehydration of the hydroxides taking place below 225 °C preserves the brucite-type structure of the samples while suppressing the stacking disorder. Copper substitution greatly enhances the bactericidal activity of nanometer-sized platelets of brucite against two bacteria frequently involved in healthcare-associated-infections. 10 mol% of cupric ions in Mg(OH)2 (a copper loading of 0.102 mg mL−1 in the suspension) were sufficient to induce, after 3 h in contact, 100% and 99.3% reductions in viability of Gram-negative E. coli and Gram-positive S. aureus, respectively (reductions as low as 23% and 48% are reported for the parent compound Mg(OH)2 in the same conditions). A good compromise between fast bactericidal kinetics and a high reduction in viability is reached by the 15 mol% copper-substituted Mg(OH)2 hydroxide. Its use gives the opportunity to five-fold reduce the copper loading of the bactericidal agent while being at least equally or even more efficient compared to the conventional CuO (a Cu loading of 0.799 mg mL−1 and 0.154 mg mL−1 in the suspension of CuO and 15 mol% copper substituted Mg(OH)2 particles, respectively).

Graphical abstract: Enhanced bactericidal activity of brucite through partial copper substitution

Supplementary files

Article information

Article type
Paper
Submitted
05 Sep 2019
Accepted
13 Nov 2019
First published
13 Nov 2019

J. Mater. Chem. B, 2020,8, 100-113

Enhanced bactericidal activity of brucite through partial copper substitution

B. Clavier, T. Baptiste, F. Massuyeau, A. Jouanneaux, A. Guiet, F. Boucher, V. Fernandez, C. Roques and G. Corbel, J. Mater. Chem. B, 2020, 8, 100 DOI: 10.1039/C9TB01927H

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