Green synthesis of capped gold nanoparticles and their effect on Gram-positive and Gram-negative bacteria

Yashvant Rao; Gajendra K Inwati; Man Singh

doi:10.4155/fsoa-2017-0062

Green synthesis of capped gold nanoparticles and their effect on Gram-positive and Gram-negative bacteria

Future Sci OA. 2017 Sep 5;3(4):FSO239. doi: 10.4155/fsoa-2017-0062. eCollection 2017 Nov.

Authors

Yashvant Rao^{1

1}, Gajendra K Inwati^{1

1}, Man Singh^{2

2}

Affiliations

¹ Centre for Nanosciences, Central University of Gujarat, Gandhinagar, Gujarat, India.
² School of Chemical Sciences, Central University of Gujarat, Gandhinagar, Gujarat, India.

Abstract

Aim: We report synthesis of capped gold nanoparticles (C-AuNPs) of ≈20-30 nm by reducing HAuCl₄ with flower and leaf extracts of Ocimum tenuiflorum, leaves of Azadirachta indica and Mentha spicata and peel of Citrus sinensis plants.

Methods: Atomic force microscopy (AFM) and transmission electron microscopy (TEM) determined their size, shape and topographical structures. The C-AuNPs with UV-Vis spectrophotometer produced a maximum absorption within 530-535 nm wavelengths. Their Fourier transform IR stretching frequencies, from 450 to 4000 cm^-1, have inferred HAuCl₄ reduction to Au.

Results: The 512 and 600 μgml^-1 C-AuNP MICs were expressed on antimicrobial strains Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively.

Conclusion: The chosen plant extracts have reduced the Au³⁺ to Au⁰ with simultaneous in situ capping with bacteria inhibiting activities. Green routes for C-AuNP synthesis could be an asset for several other biomedical and bioengineering applications.

Keywords: AFM; FTIR; MIC; TEM; antibacterial; nanomedicines; natural synthesis.