Green-synthesized gold nanoparticles from Plumeria alba flower extract to augment catalytic degradation of organic dyes and inhibit bacterial growth--颗粒学报PARTICUOLOGY

Mata, R., Bhaskaran, A., & Sadras, S. R. (2016). Green-synthesized gold nanoparticles from Plumeria alba flower extract to augment catalytic degradation of organic dyes and inhibit bacterial growth. Particuology, 24, 78-86. https://doi.org/10.1016/j.partic.2014.12.014

Green-synthesized gold nanoparticles from Plumeria alba flower extract to augment catalytic degradation of organic dyes and inhibit bacterial growth

Rani Mata, Aswathy Bhaskaran, Sudha Rani Sadras ^*

Department of Biochemistry and Molecular Biology, School of Life Sciences, Pondicherry University, Pondicherry 605014, India

10.1016/j.partic.2014.12.014

Volume 24, February 2016, Pages 78-86

Received 13 October 2014, Revised 24 December 2014, Accepted 29 December 2014, Available online 7 June 2015, Version of Record 21 January 2016.

E-mail: dr.ssrlab@gmail.com

Highlights

• Gold nanoparticles were successfully synthesized from Plumeria alba flower extract.

• The size of the gold nanoparticles could be controlled by varying concentrations of flower extract.

• Small size gold nanoparticles exhibited better antibacterial and catalytic activity.

• Mechanism of catalysis was explained.

Abstract

Bio-inspired eco-friendly gold nanoparticles were synthesized by a green method using aqueous Plumeria alba flower extract (PAFE). The use of 1% and 5% concentrations of PAFE resulted in two different sizes of P. alba gold nanoparticles, PAGNPs1 and PAGNPs2, with surface plasmon resonance (SPR) peaks at 552 and 536 nm, respectively. Size-controlled formation of gold nanoparticles was indicated by the SPR shift observed with increasing concentration of PAFE. The accurate size and morphology of PAGNPs1 and PAGNPs2 were determined by transmission electron microscope (TEM) analysis is found to be 28 ± 5.6 and 15.6 ± 3.4 nm, respectively, and those are spherical in shape. The antibacterial activity of PAGNPs1 and PAGNPs2 was tested against Escherichia coli; the small-sized PAGNPs2 exhibited better antibacterial activity with a 16-mm zone of inhibition at a concentration of 400 μg/mL. Furthermore, the catalytic activity of PAGNPs1 and PAGNPs2 was analyzed on six hazardous dyes; PAGNPs2 exhibited more pronounced catalytic activity than PAGNPs1. Among all of the dyes, 4-nitrophenol was most rapidly degraded to 4-aminophenol by PAGNPs2 within 5 min. The mechanism of catalysis in the presence of PAGNPs1 and PAGNPs2 can be described as an electron transfer process from donor NaBH₄ to an acceptor. The facile green synthesis of such eco-friendly nanoparticles in bulk suggests this method has potential industrial applications.

Graphical abstract

Keywords

Plumeria alba flower extract; Gold nanoparticles; Size control; Antibacterial; Catalytic efficiency

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