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

In this study, we have investigated the potential of bimetallic hollow nanostructures (BHNS) consisting of silver and gold metals for the detection of mercury in an aqueous medium. The BHNS of varying compositions of gold and silver were prepared by galvanic etching of the template silver nanoparticles (AgNPs) using gold(III) salt solution. The BHNS of varying composition were prepared by modulating the molar ratio, of gold to silver, ranging from 0.13 to 2.0, in the reaction mixture. The resultant nanostructures were characterized using UV-Vis spectroscopy and transmission electron microscopy. The absorption maxima of the BHNS batches were found to be increased from 463 ± 9 nm to 611 ± 12 nm as a function of gold to silver molar ratio. An increase in the nanoparticles size was observed from 54 ± 6 (molar ratio = 0.25) to 75 ± 10 (molar ratio = 2.0) with an increase in gold to silver molar ratio. The interaction of different volumes of mercury solution (ranging from 0.1 to 0.4 mL) with all types of BHNS was studied. A considerable change in color of the solution was observed and consequently, a change in the absorbance intensity and a shift in the peak plasmonic wavelength was also noticed. Among the different BHNS batches investigated, the highest change in the intensity and peak wavelength was observed for BHNS0.13, with higher silver and lower gold content. This suggests that the reaction between silver and mercury is more favored compared to that between mercury and gold. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

Department of English

School of Social Sciences & Languages

Vellore Campus

World University root node

Nanophotonics VII

Investigation of bimetallic hollow nanoparticles for colorimetric detection of mercury

The development of resistance to antimicrobial agents has been the major concern in the aquaculture industry. Essential oil nanoemulsions can be an effective alternative to the synthetic antimicrobial compounds, as they are efficient and safer to the environment. This study deals with the formulation, characterisation, application and biosafety of the black pepper oil nanoemulsion prepared using high-pressure homogenization method. A stable formulation of black pepper oil nanoemulsion was obtained with the oil and surfactant (Tween 80) ratio of 1:2. The mean droplet size and polydispersity index of the nanoemulsion was found to be 30.3 ± 2 nm and 0.21 respectively. The antibacterial activity of the black pepper oil nanoemulsion against the bacterial pathogen Pseudomonas aeruginosa as studied by microbroth dilution method was found to be 0.234 μl/ml. SEM analysis of the nanoemulsion treated bacterial cells showed significant membrane damage and the results were corroborative with the cell membrane integrity study. The MIC of black pepper oil nanoemulsion was found to be very effective in inhibiting the biofilm formation of P. aeruginosa (0.234 μl/ml) as evident from the Congo red dye reduction assay. Further the in vivo antibacterial efficacy of the black pepper oil nanoemulsion was tested on the shrimp (Penaeus monodon) and the MIC value of (0.234 μl/ml) was found effective in controlling the bacterial infection. Biosafety studies of blackpepper oil nanoemulsion on Artemia salina reveals the nontoxic nature of formulated nanoemulsion. The above findings envisage that black pepper oil nanoemulsion can be used as a potent antimicrobial agent for the control of bacterial infections in aquaculture industry. © 2018 Elsevier B.V.

VIT Unitversity

Aquaculture

Antimicrobial potency of high-energy emulsified black pepper oil nanoemulsion against aquaculture pathogen

Mosquitoes, being a vector for some potentially dreadful diseases, pose a considerable threat to people all around the world. The control over the growth and propagation of mosquitoes comprises conventional pesticides, insect growth regulators and other microbial control agents. However, the usage of these common chemicals and conventional pesticides eventually has a negative impact on human health as well as the environment, which therefore becomes a major concern. The lacuna allows nanotechnology to come into action and exploit nanopesticides. Nanopesticides are majorly divided into two categories—synthetic and biological. Several nanoformulations serve as a promising nanopesticide viz. nanoparticles, e.g. biologically synthesised nanoparticles through plant extracts, nanoemulsions prepared using the essential oils like neem oil and citronella oil and nanoemulsion of conventional pesticides like pyrethroids. These green approaches of synthesising nanopesticides make use of non-toxic and biologically derived compounds and hence are eco-friendly with a better target specificity. Even though there are numerous evidences to show the effectiveness of these nanopesticides, very few efforts have been made to study the possible non-target effects on other organisms prevalent in the aquatic ecosystem. This study focuses on the role of these nanopesticides towards the vector control and its eco-safe property against the other non-target species. © 2017, Springer-Verlag GmbH Germany.

Environmental Science and Pollution Research

Biological nanopesticides: a greener approach towards the mosquito vector control

Owing to the increase in the usage of titanium dioxide nanoparticles (TiO2 NPs), their release into the aquatic environment is inevitable. In the aquatic ecosystem, TiO2 NPs can bio-magnify at various trophic levels in the food chain through dietary exposure. In the current study, the trophic transfer potential of two crystalline phases of TiO2 anatase and rutile nanoparticles (individual as well as a binary mixture) has been evaluated in the lake water matrix using algae–daphnia system. Chlorella sp. and Ceriodaphnia dubia were used as test organisms to represent the algae–daphnia food chain of the freshwater ecosystem. Other than crystallinity, the effect of irradiation (visible and UV-A) was also investigated at the test concentrations, 75, 300, and 1200 μM. TiO2 NPs treated algal diet produced significant mortality only at the test concentrations, 300 and 1200 μM. The type of irradiation and crystallinity doesn't have any impact on the mortality of daphnids through the dietary exposure of TiO2 NPs. Comparing the mixture with individual NPs, binary mixture induced less mortality on C. dubia which signifies the antagonistic effect of NPs when they coexist. Statistical modeling confirmed the antagonistic effect of the binary mixture on C. dubia. As individual NPs, anatase and rutile forms showed a maximum Ti accumulation under UV-A and visible irradiation, respectively. BMF of TiO2 NPs has been in validation with the bioaccumulation noted in C. dubia. Individual NPs (75 μM) showed higher BMF value of ∼23 under both UV-A (anatase) and visible (rutile) irradiation. Individual NPs showing higher BMF confirmed their trophic transfer potential in the aquatic food chain, primarily through the diet. In contrast, the binary mixture obtained a higher BMF of 1.9 and 0.79 at 75 and 300 μM under visible and UV-A irradiation, respectively. The plausible reason behind this decrement was the antagonistic effect of the mixture which significantly reduced their Ti bioaccumulation on C. dubia. © 2018 Elsevier B.V.

Aquatic Toxicology

Trophic transfer potential of two different crystalline phases of TiO2 NPs from Chlorella sp. to Ceriodaphnia dubia

Zero valent iron nanoparticles (nZVI) were synthesized using anaerobic granular sludge under anaerobic conditions. UV–vis spectroscopy, X-ray diffraction, Fourier Transform Infrared spectroscopy and SEM-EDX were used for characterization of Bio-nZVI. The nZVI loaded anaerobic granular sludge (Bio-nZVI) was subsequently evaluated for removing methyl orange from aqueous solutions. Central composite design with three level factors has been employed for the determination of efficient process parameters such as methyl orange initial concentration (10–50 mg/L), weight of anaerobic granules (10–30 mg dry weight) and interaction time (90–240 min) for methyl orange removal from aqueous solution. Under the optimized conditions (weight of Bio-nZVI: 30 mg; interaction time: 240 min and initial methyl orange concentration: 10 mg/L), the removal percentage and removal capacity was found to be 99% and 168 mg/g respectively. The reduction of methyl orange by Bio-nZVI followed pseudo-second order kinetics. The granules were characterized for possible changes in the morphology and surface chemistry after methyl orange removal. The process applicability was further evaluated for removing methyl orange from ground water and lake water samples spiked with known concentrations of methyl orange. © 2018 Elsevier Ltd

Journal of Environmental Chemical Engineering

Biogenic nano zero valent iron (Bio-nZVI) anaerobic granules for textile dye removal

Carbon embedded magnetic ferrite materials are highly active, stable and being widely used in catalysis and pollution control. The carbon containing magnetic copper ferrite was synthesised by solvothermal decomposition method using precursor derived from e-waste. The prepared material was characterized by PXRD, FE-SEM, TEM, Raman, FT-IR, XPS, and NH3-TPD. During the solvothermal decomposition of Fe3(OCH3CH3COO)5·2CH3OH and Cu(CH3COO)2 in-situ generated CO2 would act as a reducing agent for M+3 to M+2 ions reduction and can also be used as carbon source. The as-synthesised copper ferrite (C@CF) was calcined at 400 °C was designated as CF. Both the materials were tested for antimicrobial activity against environmental microorganisms B. subtilis (gram positive, rod shaped) and P. aeruginosa (gram negative, rod shaped) at three exposure concentrations 50, 100 and 200 μg/ml. The possible mechanistic aspects of the antimicrobial actions for CF and C@CF was studied by reactive oxygen species generation and cell membrane permeability assays. C@CF nanoparticles consistently showed significantly higher cytotoxic effects against the test species compared to the CF particles, and this was strongly corroborated by the reactive oxygen species generation and the cell membrane damage results. © 2018 Elsevier B.V.

Department of Structural and Geotechical Engineering

School of Civil Engineering

Materials Chemistry and Physics

Solvothermal synthesis of magnetic copper ferrite nano sheet and its antimicrobial studies

Metagenomic analysis of biofilm forming bacteria in environmental samples remains challenging due to the non-availability of gene sequences of most of the uncultivable bacteria. Sequences of Pseudomonas aeruginosa PAO1-UW genes involved either directly or indirectly in biofilm formation were analyzed using BLASTn to obtain matching sequences from different strain, species and genus. Conserved regions in the functional domain of the amino acid sequences were used to design common primers for direct PCR analysis of freshwater metagenomes. Seven key genes such as aceA, clpP, typA, cbrA, phoR, rpoS and gacA involved in biofilm formation were validated. The ortholog genes belonged to wide range of Pseudomonas sp. indicating the diversity of biofilm genes and the conservation of protein functional domains. The approach would also help in analyzing the expression of biofilm genes in different bacteria of freshwater systems for monitoring toxic contaminations such as organic or inorganic pollutants. © 2017 Elsevier Inc.

Department of Biotechnology

School of Bio Sciences and Technology

Fulltext

Genomics

Gene-centric metegenome analysis reveals diversity of Pseudomonas aeruginosa biofilm gene orthologs in fresh water ecosystem

A systems biology approach was used to study all the biofilm related genes of P. aeruginosa PAO1, and the interaction of titanium dioxide (TiO2) anatase with biofilm related proteins. Among the 71 genes, the interactions of all the nodal pairs were extracted by STRING 10.5 database. The inter-relationship among these genes was predicted by constructing complete PPI network and visualized in Cytoscape v 3.4.0. Total number of nodes of the network was found to be 335 and edges were 795. The network was further investigated for its clusters and the best cluster was further analyzed for the hub proteins which significantly contribute in cross-regulation of the biofilm related process. The hub proteins were identified based on four topological parameters of degree, closeness, betweeness and radiality. Four major hub proteins of P. aeruginosa PAO1 were identified to be algD, gacS, rpoS and rpoN which were common in all the hubs. Further, we have also elucidated the probable mechanism of TiO2 interaction with P. aeruginosa PAO1 at molecular level. Using STITCH server, the major target gene of TiO2 was identified as katA which also appeared commonly in our main dataset and this gene has been focused for the further study because of its unique common appearance in gene–gene network as well as gene-anatase network. The direct interacting partners of katA were found to be dnaK, hfq, rpoS and rpoA. Based on these findings and available gene regulatory information, probable TiO2 interacting cascade has been represented. This in silico study of P. aeruginosa PAO1 biofilm genes and the interaction of protein products with TiO2 might be significant to understand the perspective pathogenic resistance as well as the toxicity research pertaining to nanoparticles. © 2018 Elsevier B.V.

Gene

Cross-regulatory network in Pseudomonas aeruginosa biofilm genes and TiO 2 anatase induced molecular perturbations in key proteins unraveled by a systems biology approach

A sequential method for removing Cr(VI) was studied using polymer-nano zero valent iron (nZVI)-based composite film and live biomass of sulfate reducing bacteria (SRB) under anaerobic conditions. The polymer-nZVI composite film was made using layer-by-layer coating of chitosan, polyethylene glycol (PEG) blend, poly (sodium 4-styrene sulphonate) solution (PSS), and nZVI on a glass slide. The conditions for the removal of Cr(VI) through polymer-nZVI nanocomposite film were optimized using Response Surface Methodology (RSM). SRB was grown in Baar's medium was adapted to 10 mg L−1 of Cr(VI) and the live biomass obtained thereof was used for removal of Cr(VI). Cr(VI) removal capacity of 394 mg g−1 was observed at optimal conditions by nano-bio sequential removal process using polymer-nZVI-based composite film and SRB. The XRD, SEM-EDX, and FT-IR spectral data demonstrated the reduction of Cr(VI) and binding of chromium (Cr) species on the polymer-nZVI-based composite film and SRB biomass. The applicability of the sequential Cr(VI) removal process using polymer-nZVI-based composite film and SRB was successfully verified in Cr(VI)-spiked environmental water samples.

Environmental Technology & Innovation

Nano-Bio sequential removal of hexavalent chromium using polymer-nZVI composite film and sulfate reducing bacteria under anaerobic condition

Polysaccharide from red seaweed Gracilaria folifera has an interesting functional property of antioxidant activity and prebiotic effect. A feeding trial experiment was directed to examine the effect of probiotic bacteria Bacillus vireti 01 microencapsulated with G. folifera polysaccharide against freshwater prawn M. rosenbergii. Three different feeding trials were conducted for 15 days. The first group contained prawns fed with commercial diet. The second group was comprised of Aeromonas hydrophila challenged prawns fed with commercial feed. The third group consisted of A. hydrophila challenged prawns fed with microencapsulated probiotic-polysaccharide. Survival percentage was significantly decreased in prawns of group2 as compared to that of group1 and group3 prawns (p

Fish & Shellfish Immunology

Effect of microencapsulated probiotic Bacillus vireti 01-polysaccharide extract of Gracilaria folifera with alginate-chitosan on immunity, antioxidant activity and disease resistance of Macrobrachium rosenbergii against Aeromonas hydrophila infection