The adsorption of exopolysaccharides (EPS) on silver nanoparticles (SNPs) was influenced by pH, salt concentration, and zeta potential. In this paper, SNPs were stabilized using exopolysaccharides (EPS) produced by Aeromonas punctata as the capping agent. The effects of EPS concentration on the adsorption was studied by UV-visible absorption spectra. During interaction, a decrease in absorbance at plasmon peak of SNPs (425. nm) was observed till 50. mg/L of EPS, beyond that a blue shift towards 411. nm was observed. The capping of SNPs by EPS was confirmed by Fourier Transform Infrared Spectroscopy. The adsorption of EPS on nanoparticles was found to be strongly dependent on zeta potential. The equilibrium adsorption data fitted well by Langmuir isotherm compared to Freundlich curve. The kinetics of adsorption was fitted by pseudo-second-order. Desorption of EPS from SNPs was observed at alkaline pH 12. The stabilized silver nanoparticles could be more amenable towards applications in biotechnology and bioengineering. © 2011 Elsevier B.V.

Chandra Sekaran N

Centre for Nanobiotechnology

Vellore Campus

Amitava Mukherjee

Sudheer Khan S

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Use of silver nanoparticles (SNPs) is increasing in a large number of consumer products. Thus, the possible build-up of the nanoparticles in the environment is becoming a major concern. Aeromonas punctata isolated from sewage showed tolerance to 200 μg/ml SNPs. The growth kinetics data for A. punctata treated with nanoparticles were similar to those in the absence of nanoparticles. There was a reduction in the amount of exopolysaccharides (EPS) in bacterial culture supernatant after nanoparticle-supernatant interaction. EPS capping of the nanoparticles was confirmed by UV-visible, XRD and comparative FTIR analysis. The EPS-capped SNPs showed less toxicity to Escherichia coli, Staphylococcus aureus and Micrococcus luteus compared to the uncapped ones. The study suggests capping of nanoparticles by bacterially produced EPS as a probable physiological defense mechanism. © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Journal of Basic Microbiology

Bacterial tolerance to silver nanoparticles (SNPs): Aeromonas punctata isolated from sewage environment

Biofunctionalization of noble metal nanoparticles like Ag, Au is essential to obtain biocompatibility for specific biomedical applications. Silver nanoparticles are being increasingly used in bio-sensing applications owing to excellent optoelectronic properties. Among the serum albumins, the most abundant proteins in plasma, a wide range of physiological functions of Bovine Serum Albumin (BSA) has made it a model system for biofunctionalization. In absence of adequate prior reports, this study aims to investigate the interaction between silver nanoparticles and BSA. The interaction of BSA [0.05-0.85% concentrations] with Ag nanoparticles [50 ppm concentration] in aqueous dispersion was studied through UV-vis spectral changes, morphological and surface structural changes. At pH 7, which is more than the isoelectric point of BSA, a decrease in absorbance at plasmon peak of uninteracted nanoparticles (425 nm) was noted till 0.45% BSA, beyond that a blue shift towards 410 nm was observed. The blue shift may be attributed to enhanced electron density on the particle surfaces. Increasing pH to 12 enhanced the blue shift further to 400 nm. The conformational changes in BSA at alkaline pH ranges and consequent hydrophobic interactions also played an important role. The equilibrium adsorption data fitted better to Freundlich isotherm compared to Langmuir curve. The X-ray diffraction study revealed complete coverage of Ag nanoparticles by BSA. The scanning electron microscopic study of the interacted nanoparticles was also carried out to decipher morphological changes. This study established that tailoring the concentration of BSA and pH of the interaction it was possible to reduce aggregation of nanoparticles. Biofunctionalized Ag nanoparticles with reduced aggregation will be more amenable towards bio-sensing applications. © 2009 Elsevier B.V. All rights reserved.

Colloids and Surfaces B: Biointerfaces

Studies on interaction of colloidal Ag nanoparticles with Bovine Serum Albumin (BSA)

Biotechnology Advances

Retraction notice to “Nanosilver — The burgeoning therapeutic molecule and its green synthesis” [Biotech Adv. 27 (2009) 924–937]

Nanotechnology

Interaction of multi-functional silver nanoparticles with living cells

Nanotoxicology

Emerging trends of nanoparticles application in food technology: Safety paradigms

Interaction of colloidal silver nanoparticles (SNPs) with exopolysaccharides (EPS) and its adsorption isotherms and kinetics

Journal	Data powered by TypesetColloids and Surfaces A: Physicochemical and Engineering Aspects
Publisher	Data powered by TypesetElsevier BV
ISSN	0927-7757
Open Access	0