Effect of pH variations on morphological transformation of biosynthesized MgO nanoparticles

Abstract

Plant leaf extract synthesis of nanoparticles serves as a better alternative to chemical synthesis routes as the nanoparticles synthesized are less toxic and possess higher flexibility for scaling up process. Phyto-synthesized metal oxides, especially magnesium oxide (MgO) nanoparticles possess enormous unique properties to be used in drug delivery and therapeutic application. Thus, the aim of the present work is to investigate the effect of pH on the shape transformation of MgO nanoparticles prepared using Amaranthus tricolor leaf extract. UV-visible spectrophotometer and dynamic light scattering technique were initially used to analyze the effect of pH variation on particle sizes and surface charges. MgO nanoparticles at pH 3 were identified to be formed in smaller sizes of ∼44nm with a slightly negative surface charge of −3.39 mV and were postulated that its shape can be transformed to hexagon. Hexagonal shaped particles are highly beneficial in biomedical application as they show less cytotoxicity and increased bioactivity due to the presence of edge surface atoms. FTIR spectral analysis and TEM images confirm that the size and shape of the MgO nanoparticle at acidic pH 3 was reduced and transformed to hexagon. Additionally, possible mechanism of nanoparticle protonation and deprotonation leading to their morphology changes was also proposed in the paper.

Keywords:

• pH variation
• MgO nanoparticles
• hexagon morphology; A. tricolor leaf extract
• biosynthesis

Acknowledgments

The authors wish to acknowledge Curtin University, Malaysia, for their financial support through the Curtin Sarawak Postgraduate Research Scholarship (CSPRS) scheme.

Disclosure statement

The authors declare that they have no conflict of interest.