TITLE:
Effects of Precipitation Temperature on Nanoparticle Surface Area and Antibacterial Behaviour of Mg(OH)2 and MgO Nanoparticles
AUTHORS:
Banele Vatsha, Phumlani Tetyana, Poslet Morgan Shumbula, Jane Catherine Ngila, Lucky Mashudu Sikhwivhilu, Richard Motlhaletsi Moutloali
KEYWORDS:
MgO; Nanoparticles; Precipitation; Crystallinity; Antibacterial
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.4 No.4,
October
17,
2013
ABSTRACT:
A series of
MgO nanoparticles were prepared by first precipitating and isolating Mg(OH)2 nanoparticles from Mg(NO3)2 at three different temperatures
using NaOH followed by their thermal decomposition also at three temperature settings. The effects of temperature at which
precipitation and thermal decomposition of the hydroxide occurred were studied
to assess their influence on nanoparticle size and surface area. The
synthesised nanoparticles were characterized using
a suite of techniques including Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD),
Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM)
analysis. The average diameter range of MgO nanoparticles ranged between 15 and
35 nm, while for the precursor Mg(OH)2 it varied between 28 and 45 nm. The nanoparticle
surface area obtained from BET studies was found in all cases to increase from
77 to 106.4 m2/g with increasing
temperature of precipitation. Antibacterial activities of the prepared Mg(OH)2 and MgO nanoparticles were evaluated against the Gram-negative bacteria, Escherichia coli, and the Gram-positive
bacteria, Staphylococcus aureus,
using agar diffusion method. A correlation between surface area and
antibacterial activity supported the mechanism of bacterial inactivation as the
generation of reactive species. The Mg(OH)2 and MgO nanoparticles
both exhibited pronounced bactericidal
activity towards the Gram positive bacteria than Gram negative bacteria as
indicated by the extend of the zone of inhibition around the
nanoparticle.