Centre for Nanobiotechnology

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

Owing to widespread applications, synthesis and characterization of silver nanoparticles is recently attracting considerable attention. Increasing environmental concerns over chemical synthesis routes have resulted in attempts to develop biomimetic approaches. One of them is synthesis using plant parts, which eliminates the elaborate process of maintaining the microbial culture and often found to be kinetically favourable than other bioprocesses. The present study deals with investigating the effect of process variables like reductant concentrations, reaction pH, mixing ratio of the reactants and interaction time on the morphology and size of silver nanoparticles synthesized using aqueous extract of Azadirachta indica (Neem) leaves. The formation of crystalline silver nanoparticles was confirmed using X-ray diffraction analysis. By means of UV spectroscopy, Scanning and Transmission Electron Microscopy techniques, it was observed that the morphology and size of the nanoparticles were strongly dependent on the process parameters. Within 4 h interaction period, nanoparticles below 20-nm-size with nearly spherical shape were produced. On increasing interaction time (ageing) to 66 days, both aggregation and shape anisotropy (ellipsoidal, polyhedral and capsular) of the particles increased. In alkaline pH range, the stability of cluster distribution increased with a declined tendency for aggregation of the particles. It can be inferred from the study that fine tuning the bioprocess parameters will enhance possibilities of desired nano-product tailor made for particular applications. © 2009 Springer Science+Business Media B.V.

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Journal of Nanoparticle Research

Process variables in biomimetic synthesis of silver nanoparticles by aqueous extract of Azadirachta indica (Neem) leaves

The aim of the study was to investigate the antibacterial activity of refined Sunflower oil, Tween 20 (polyoxyethylene (20) sorbitan monolaurate), water microemulsion system. Pseudo-ternary phase diagram was constructed to obtain the concentration range of oil, surfactant and water. Three microemulsion formulations were prepared, of which oil, tween 20 and water were made to 100 %. Conductivity and pH were used to characterize microemulsion. The concentration of refined sunflower oil varied from 5% to 15 %, the surfactant concentration varied from 10 % to 30 % and water concentration varied from 55 % to 85 %. When water concentration increases, conductivity of the microemulsion system increases upto 50 % of water concentration and after that become stable. When oil and surfactant concentration was increased, pH of the microemulsion system decreases. Kinetic studies showed inhibition of bacterial growth in all formulated microemulsions. Bacterial growth was enhanced in the case of oil and surfactant alone.

International Journal of Pharmacy and Pharmaceutical Sciences

Anti bacterial activity of sunflower oil microemulsion

Tanneries in Ambur, Vaniambadi, Pernambut, Ranipet and Walajapet are clustered on the banks of the Palar River. This is the primary source of drinking water for the residents of Vellore district. Reports have shown that the soil and ground water of these places are heavily contaminated with salts and heavy metals especially Chromium. The water quality parameters in the area are found to be above the W HO permissible limits (0.05 mg/L). Based on the basic survey on tanneries and its pollution in the Vellore District, our studies focused on bio-remediation of tannery effluents, which is the main source of contamination. As our basic study is to improve our understanding to find the Cr contamination level and the ecology of heavy metal tolerance of the native bacterial flora of our study area, Chromium resistant strains were isolated from contaminated water and sediments of various tanneries. This study reports the chromium contamination and the chromium resistant bacterial populations in the Vellore District in relation to seasonal variations. © Maxwell Scientific Organization, 2010.

Research Journal of Applied Sciences, Engineering and Technology

Seasonal variations in the chromium concentration and chromium resistant bacterial populations in Vellore district

The aim of this paper is to study the effect of dendrimeric and non-dendrimeric support in surface plasmon resonance (SPR) sensors for proteineous antigen analysis. 11-mercapto undecanoic acid (MUA) linker was chosen to fabricate the non-dendrimeric sensor surface while fourth generation poly(amidoamine) (PAMAM) dendrimer was used to design the dendrimeric sensor support on gold disks. Both the surfaces were conjugated with human immunoglobulin G (HIgG) antibodies and the binding was monitored in real time on Autolab Twingle SPR system. Antibodies were covalently attached to the MUA surface using EDC-NHS chemistry while glutaraldehyde was used as linker to conjugate antibodies on MUA-PAMAM surface. Further, both the sensor supports were used to study the antigen-antibody interaction using goat anti-human immunoglobulin (GaHIgG) antigen as sample analyte. Through SPR measurements, we found that dendrimeric sensor support exhibited two fold enhanced signal for HIgG binding than that of MUA surface only. During GaHIgG interaction, dendrimer modified sensor surface displayed enhanced signal with respect to the non-dendrimeric surface. This enhanced sensor response of dendrimeric SPR sensor support is attributed to high functional group density, globular shape and greater accessibility of immobilized probe towards analyte interaction. © 2010 IEEE.

International Conference on Systems in Medicine and Biology, ICSMB 2010 - Proceedings

Potential of dendrimeric architecture in surface plasmon resonance biosensor

Journal of Fish Diseases

Efficacy of bacterially expressed dsRNA specific to different structural genes of white spot syndrome virus (WSSV) in protection of shrimp from WSSV infection

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Indian Journal of Critical Care Medicine

A computer-assisted recording, diagnosis and management of the medically ill system for use in the intensive care unit: A preliminary report

Metal oxide nanoparticles (NPs) are known to possess strong antimicrobial properties. Aluminum oxide NPs have wide-range applications in industrial as well as personal care products. In the absence of prior reports on the antimicrobial properties of alumina NPs for a wide concentration range, the principal objective of the present work was to study the growth-inhibitory effect of alumina NPs over a wide concentration range (10-1000 μg/mL) on an environmentally relevant gram-negative model microorganism, Escherichia coli. The mean diameter of the NPs was determined to be 179 nm in aqueous dispersion used for this study, and surface area was determined to be 21.23 m2/g. The concentration of 1000 μg/mL was found to be moderately inhibitory for bacteria. Almost negligible dependence of growth rate on the concentration of the NPs was observed. The extracellular protein content was found to be slightly lower in case of cells interacting with 1000 μg/mL alumina than the uninteracted control cells. Fourier transform-infrared studies established differences in structure between interacted and uninteracted cells. Alumina NPs showed a mild growth-inhibitory effect, only at very high concentrations, which might be due to surface charge interactions between the particles and cells. Free-radical scavenging properties of the particles might have prevented cell wall disruption and drastic antimicrobial action. This laboratory-scale study suggests that alumina NPs may only exhibit mild toxicity toward microorganisms in the environment. From the Clinical Editor: Metal oxide NPs, inluding aluminum oxide NPs, are known to possess strong antimicrobial properties. The study demonstrated a mild to moderate growth-inhibitory effect of alumina NPs over a wide concentration range (10-1000 μg/mL) on Escherichia coli. Almost negligible dependence on the concentration was observed. © 2009 Elsevier Inc. All rights reserved.

Nanomedicine: Nanotechnology, Biology and Medicine

Antimicrobial sensitivity of Escherichia coli to alumina nanoparticles

Potential health and environmental effects of nanoparticles need to be thoroughly assessed before their widespread commercialization. Though there are few studies on cytotoxicity of nanoparticles on mammalian and human cell lines, there are hardly any reports on genotoxic and cytotoxic behavior of nanoparticles in plant cells. This study aims to investigate cytotoxic and genotoxic impacts of silver nanoparticles using root tip cells of Allium cepa as an indicator organism. A. cepa root tip cells were treated with four different concentrations (25, 20, 75, and 100 ppm) of engineered silver nanoparticles (below 100 nm size) dispersion, to study endpoints like mitotic index, distribution of cells in mitotic phases, different types of chromosomal aberrations, disturbed metaphase, sticky chromosome, cell wall disintegration, and breaks. For each concentration five sets of microscopic observations were carried out. No chromosomal aberration was observed in the control (untreated onion root tips) and the mitotic index (MI) value was 60.3%. With increasing concentration of the nanoparticles decrease in the mitotic index was noticed (60.30% to 27.62%). The different cytological effects including the chromosomal aberrations were studied in detail for the treated cells as well as control. We infer from this study that silver nanoparticles could penetrate plant system and may impair stages of cell division causing chromatin bridge, stickiness, disturbed metaphase, multiple chromosomal breaks and cell disintegration. The findings also suggest that plants as an important component of the ecosystems need to be included when evaluating the overall toxicological impact of the nanoparticles in the environment. © 2009 Elsevier B.V. All rights reserved.

Science of The Total Environment

Genotoxicity of silver nanoparticles in Allium cepa

Silver nanoparticles are known to have bactericidal effects. A new generation of dressings incorporating antimicrobial agents like silver nanoparticles is being formulated to reduce or prevent infections. The particles can be incorporated in materials and cloth rendering them sterile. Recently, it was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Apart from being environmentally friendly process, use of Neem leaves extract might add synergistic antibacterial effect of Neem leaves to the biosynthesized nanoparticles. With this hypothesis the biosynthetic production of silver nanoparticles by aqueous extract of Neem leaves and its bactericidal effect in cotton cloth against E. Coli were studied in this work. Silver nanoparticles were synthesized by short term (1 day) and long term (21 days) interaction of Neem extract (20% w/v) and 0.01 M AgNO3 solution in 1:4 mixing ratio. The synthesized particles were characterized by UV visible spectroscopy, transmission electron microscopy, and incorporated into cotton disks by (i) centrifuging the disks with liquid broth containing nanoparticles, (ii) in-situ coating process during synthesis, and (iii) coating with dried and purified nanoparticles. The antibacterial property of the nanoparticles coated cotton disks was studied by disk diffusion method. The effect of consecutive washing of the coated disks with distilled water on antibacterial property was also investigated. This work demonstrates the possible use of biologically synthesized silver nanoparticles by its incorporation in cloths leading them to sterilization. Copyright © 2009 American Scientific Publishers All rights reserved.

Journal of Biomedical Nanotechnology

Antibacterial Applications of Silver Nanoparticles Synthesized by Aqueous Extract of Azadirachta Indica (Neem) Leaves

The aim of the study was investigate antifungal activity of the various leaves extracs of Achyranthes aspera Linn.The aqueous,ethanol and methanol leaves extracts of Achyranthes aspera Linn. (Family:Amaranthaceae) were evaluated for antifungal activity against clinically important fungal spp viz. Candida albicans (MTCC 227), C.tropicalis (MTCC 750), C.krusei (ATCC 6258), C.kefyr (ATCC 4235), C. guilliermondi (ATCC 6260),C.glabrata (ATCC 2001),Cryptococcus neoformans (MTCC 1346), Aspergillus niger (MTCC 277), Aspergillus fumigatus (MTCC 343) , Aspergillus flavus (MTCC 418), Rhizopus oryzae (MTCC 262).The in vitro antifungal activity was performed by agar well diffusion method. The ethanol extract of the leaves of Achyranthes aspera Linn revealed an elevated antifungal activity against C.kefyr, Cryptococcus neoformans, Aspergillus niger and Aspergillus flavus. The methanol extract of the leaves showed higher antifungal activity against Cryptococcus neoformans and Aspergillus flavus. Aqueous extract of the leaves did not show activity against tested fungal strains. The results obtained in the present study suggest that the ethanol and methanol extracts of the leaves of Achyranthes aspera Linn revealed a significant scope to develop a novel broad spectrum of antifungal herbal formulation.