Biosynthesis of stable antioxidant ZnO nanoparticles by Pseudomonas aeruginosa rhamnolipids

• Published in: PloS one Vol. 9; no. 9; p. e106937
• Main Authors: Singh, Brahma Nand, Rawat, Ajay Kumar Singh, Khan, Wasi, Naqvi, Alim H, Singh, Braj Raj
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04-09-2014; Public Library of Science (PLoS)
• Subjects: Analysis; Antimicrobial agents; Antioxidants; Antioxidants (Nutrients); Antioxidants - chemistry; Applied physics; Beta carotene; beta Carotene - chemistry; Biocompatibility; Biology and Life Sciences; Biosynthesis; Biphenyl Compounds - antagonists & inhibitors; Biphenyl Compounds - chemistry; Chemical properties; Chemical synthesis; Ecological risk assessment; Electron microscopy; Engineering and Technology; Engineering schools; Fourier transforms; Free radicals; Glycolipids - chemistry; Glycolipids - isolation & purification; Gravimetric analysis; Hydroxyl Radical - antagonists & inhibitors; Hydroxyl Radical - chemistry; Infrared analysis; Infrared spectroscopy; Light diffraction; Light scattering; Lipid peroxidation; Materials science; Metal Nanoparticles - chemistry; Metal Nanoparticles - ultrastructure; Nanomaterials; Nanoparticles; Oxidation; Oxidative stress; Particle Size; Peroxidation; Photon correlation spectroscopy; Phylogenetics; Picrates - antagonists & inhibitors; Picrates - chemistry; Polycrystals; Pseudomonas aeruginosa; Pseudomonas aeruginosa - chemistry; Quantum dots; Rhamnolipids; Scanning electron microscopy; Spectroscopy; Studies; Superoxide; Superoxides - antagonists & inhibitors; Superoxides - chemistry; Surfactants; Transmission electron microscopy; Wurtzite; X-ray diffraction; Zinc; Zinc oxide; Zinc Oxide - chemistry; Zinc oxides; β-Carotene
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0106937

During the last several years, various chemical methods have been used for synthesis of a variety of metal nanoparticles. Most of these methods pose severe environmental problems and biological risks; therefore the present study reports a biological route for synthesis of zinc oxide nanoparticles using Pseudomonas aeruginosa rhamnolipids (RLs) (denoted as RL@ZnO) and their antioxidant property. Formation of stable RL@ZnO nanoparticles gave mostly spherical particles with a particle size ranging from 35 to 80 nm. The RL@ZnO nanoparticles were characterized by UV-visible (UV-vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis. The UV-vis spectra presented a characteristic absorbance peak at ∼ 360 nm for synthesized RL@ZnO nanoparticles. The XRD spectrum showed that RL@ZnO nanoparticles are crystalline in nature and have typical wurtzite type polycrystals. Antioxidant potential of RL@ZnO nanoparticles was assessed through 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion free radicals with varying concentration and time of the storage up to 15 months, while it was found to decline in bare ZnO nanoparticles. Similarly, the inhibitory effects on β-carotene oxidation and lipid peroxidation were also observed. These results elucidate the significance of P. aeruginosa RL as effective stabilizing agents to develop surface protective ZnO nanoparticles, which can be used as promising antioxidants in biological system.