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

Silver and zinc oxide nanoparticles (Ag and ZnO NPs) are widely used as antimicrobial agents. However, their potential toxicological impact on environmental microorganisms is largely unexplored. The aim of this work was to investigate the sensitivity and adaptability of five bacterial species isolated from sewage towards Ag and ZnO NPs. The bacterial species were exposed to increasing concentration of nanoparticles and the growth inhibitory effect, exopolysaccharides (EPSs) and extracellular proteins (ECPs) productions were determined. The involvement of surface charge in nanoparticles toxicity was also determined. The bacterial species were constantly exposed to nanoparticles to determine the adaptation behavior toward nanoparticles. The nanoparticles exhibited remarkable growth inhibitory effect on tested bacterial species. The toxicity of nanoparticles was found to be strongly dependent on surface charge effects. Though, these organisms are highly sensitive to Ag and ZnO NPs, the continuous exposure to these nanoparticles leads to moderate adaptation of bacterial species and the adapted bacterial species convert the highly toxic nano form to less toxic microform. Finally we predict that the continuing applications of nanoparticles in consumer products may lead to the development of nanoparticles resistant bacterial strains in future. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

VIT Unitversity

Vellore Campus

Journal of Basic Microbiology

Toxic behavior of silver and zinc oxide nanoparticles on environmental microorganisms

Presence of several biochemical constituents in neem makes it an efficient antimicrobial agent for pathogenic diseases. The current investigation was aimed to assess the therapeutic potential of neem nanoemulsion as a control measure for Pseudomonas aeruginosa infection in freshwater fish Labeo rohita. The median lethal concentration (LC50) for the neem oil and neem nanoemulsion was 73.9 and 160.3 mg/L, respectively. The biomarker enzymes of treated fish tissues showed a significant difference in the level of glutathione reductase, catalase, and lipid peroxidation in neem oil-treated samples than in neem nanoemulsion-treated samples at P &lt; 0.05. The results were corroborative with histopathology and ultrastructural analysis. The bacterial infection of P. aeruginosa treated using neem nanoemulsion was more effective in both in vitro and in vivo methods. Present findings suggest that neem-based nanoemulsion has negligible toxicity to Rohu fishes. This makes neem-based nanoemulsion as an efficient therapeutic agent against P. aeruginosa infection, leading to its possible usage in the aquaculture industry. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Biotechnology and Applied Biochemistry

Study on antimicrobial potential of neem oil nanoemulsion againstPseudomonas aeruginosainfection inLabeo rohita

The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120μg/mL (196 to 1176μM) for 48h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and its probable impacts on the energy flow in the fresh water aquatic ecosystem.

Aquatic Toxicology

Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia)

The extensive environmental exposure of engineered metal oxide nanoparticles (NPs) may result in their bioaccumulation in aquatic organisms leading to their biotransfer in a food chain through various routes in a freshwater ecosystem. The present study focuses on the possible modes of TiO2 NP trophic transfer to Ceriodaphnia dubia, in presence and/absence of its diet, Scenedesmus obliquus (primary producer). The acute exposure studies (48h) were designed to have daphnids exposed to (i) the free NPs, (ii) both the free and the algae-borne NPs; and (iii) only the algae-borne NPs in separate tests to understand the possible routes of NP transfer. The dietary uptake of TiO2 NPs (algae-borne) was found to be the primary route for NP biotransfer with ~70% of total NP uptake. Interestingly, in a separate study it was noticed that the NPs coated with algal exudates were easily taken up by daphnids as compared to pristine NPs of same concentrations, leading to their higher bioaccumulation. A chronic toxicity study, where daphnids were exposed to both free and algae-borne NPs for 21 days was undertaken to comprehend the TiO2 NP effect on daphnia growth and reproduction upon chronic exposure and also the bioaccumulation potential. Both acute and chronic exposure studies suggested higher bioaccumulation of TiO2 in daphnids when the particles were less toxic to the diet (algae). © 2014 Elsevier B.V.

Different modes of TiO2 uptake by Ceriodaphnia dubia: Relevance to toxicity and bioaccumulation

Staphyloccocus aureus causes wide range of infections from being mild to crucial problems. Azithromycin macrolide have been in use for many years solving the severity of these infections. But, aqueous insolubility and resistance developed is the question of focus. Considering the need for improvement of the drug properties, we used conventional clove oil based microemulsion drug delivery system for its effective antimicrobial activity and stability of the formulation. This optimized system is prepared using clove oil, tween 20 and water (5:30:65 v/v) by gentle mixing at laboratory environment. The dynamic light scattering technique reports the droplet size range in the nanometer scale with low polydispersity index value. The better quality antibacterial action was further quantified by the liberation of UV absorbing substances at 260 nm confirming structural damage of the treated pathogen. Copyright © 2014 American Scientific Publishers

Journal of Bionanoscience

Microencapsulation of Azithromycin Shows Improved Anti-Bacterial Efficacy

AbstractFilariasis is a mosquito-borne disease that causes lymphedema and the main vector is Culex quinquefasciatus. A simple measure was taken to eradicate the vector using nanoemulsion. Eucalyptus oil nanoemulsion was formulated in various ratios comprising of eucalyptus oil, tween 80 and water by ultrasonication. The stability of nanoemulsion was observed over a period of time and 1:2 ratios of eucalyptus oil (6%) and surfactant (12%) was found to be stable. The formulated eucalyptus oil nanoemulsion was characterized by transmission electron microscopy and dynamic light scattering. The nanoemulsion droplets were found to have a Z-average diameter of 9.4 nm and were spherical in shape. The larvicidal activity of eucalyptus oil nanoemulsion and bulk emulsion was tested and compared. Our nanoemulsion showed higher activity when compared to bulk emulsion. The histopathology of larvae-treated and untreated nanoemulsion was analyzed. Furthermore, biochemical assays were carried out to examine the effect of nanoemulsion on biochemical characteristics of larvae. The treated larval homogenate showed decrease in total protein content and a significant reduction in the levels of acetylcholinesterase. The levels of acid and alkaline phosphatase also showed reduction as compared to control larval homogenate.

Fulltext

Bulletin of Entomological Research

Nanoemulsion of eucalyptus oil and its larvicidal activity against Culex quinquefasciatus

Nanoemulsions are colloidal dispersions of oil and water with droplet size in the range of 10-100 nm. They are optically transparent stable systems which require less surfactant concentration than microemulsion. Basil oil (extracted from Ocimum basilicum) nanoemulsion was formulated by spontaneous emulsification method and was stabilized by non-ionic surfactant Tween20. Process parameters like surfactant concentration, stirring speed, and holding temperature were optimized to obtain nanoemulsion with minimized droplet size and these factors demonstrated positive correlation on nanoemulsion droplet size and stability. BT20/11/800/75 nanoemulsion (oil system = basil, surfactant = Tween20, oil to surfactant mixing ratio 1:1 vol/vol, rpm = 800, pre-heating temperature of organic phase = 75 °C) showed lowest droplet size of 28 nm and greater stability. Transmission electron micrograph image showed the spherical morphology of BT20/11/800/75 nanoemulsion droplets. Formulated BT20/11/800/75 nanoemulsion was evaluated for larvicidal activity against Culex quinquefasciatus. Basil oil nanoemulsion exhibited dose-dependent mortality of C. quinquefasciatus larva which increased with increase in exposure time. Lethal concentration (LC50) value decreased from 70 to 3 mg/L-1 with increase in exposure time from 1 to 5 h. Further increase in exposure time did not show any significance reduction in LC-50 value. Histopathological staining revealed the structural and functional changes in nanoemulsion-treated larva. Epithelial cells are swollen and showed distorted morphology. Disintegration of epithelial membrane and peritrophic membrane upon nanoemulsion treatment resulted in leakage of mid-gut lumen contents. © 2014 Springer Science+Business Media New York.

BioNanoScience

Optimization of Process Parameters to Formulate Nanoemulsion by Spontaneous Emulsification: Evaluation of Larvicidal Activity Against Culex quinquefasciatus Larva

The growing need for advanced treatment of evolving diseases has become a motivation for this study. Among the noble metals, platinum nanoparticles are of importance because of their catalytic property, antioxidant potential, minimal toxicity and diverse applications. Biological process of synthesis has retained its significance, because it is a simple one-step process yielding stable nanoparticles. Herein, we have synthesised platinum nanoparticles through a green process using the unexplored seaweed Padina gymnospora, a brown alga. The course of synthesis was monitored and the nanoparticles were characterised using UV-visible spectroscopy. The synthesised nanoparticles were studied using TEM, XRD and FTIR. The TEM and XRD studies reveal the size of the nanoparticle to be &lt;35 nm. The catalytic nanoparticles were capable of oxidising NADH to NAD +. The biocompatibility was tested by haemolytic assay for the furtherance of the application of platinum nanoparticles in medicine. This is the first report on the biogenic synthesis of platinum nanoparticles using seaweed. © Springer-Verlag 2013.

Bioprocess and Biosystems Engineering

Haemocompatibility assessment of synthesised platinum nanoparticles and its implication in biology

The probable underlying mechanism(s) of bacterial cell-TiOnanoparticles (TiONPs) interaction in the absence of photo-irradiation has been less studied since most of the prior cytotoxicity studies focused on irradiated TiO The present study draws attention to the possible role of cell surface-TiONP interactions under dark conditions, through an array of spectroscopic and microscopic investigations. A dominant freshwater bacterial isolate, Bacillus licheniformis, which interacted with environmentally relevant concentrations of TiONPs (1 μg/mL), was analysed and compared under both light and dark conditions. Aggregation of cells upon NP interaction and adsorption of NPs onto the cell membrane was evident from the scanning electron micrographs under both light and dark conditions. The FT-IR and FT-Raman spectra suggested stress response of bacterial cells by elevated protein and polysaccharide content in the cell-NP interaction. The Xray photoelectron spectroscopic data substantiated the reduction of titanium from Ti(IV) to Ti(III) species which might have contributed to the redox interactions on the cell surface under light as well as dark conditions. The internalization of NPs in the cytoplasm were obvious from the transmission electron micrographs. The consequent cell death/damage was confirmed through fluorescence spectroscopy and microscopy. To conclude, the current study established the substantial role of interfacial interactions in cytotoxicity of the TiONPs irrespective of the irradiation conditions. © Indian Academy of Sciences.

Bulletin of Materials Science

Studies on interfacial interactions of TiO2 nanoparticles with bacterial cells under light and dark conditions

The plant derived essential oil nanoemulsion was prepared using a mixture of components containing eucalyptus oil as organic phase, water as continuous phase, and non ionic surfactant, Tween 80, as emulsifier at a particular proportion of 1:1 v/v%. The ultrasonication was applied for varied processing time from 0 to 30 min to study the effect of time on the formation of nanoemulsion and physical stability of formulation by this method. The transparency and stability of emulsion was enhanced when the sonication time was increased compared to hand blender emulsion. The most stable nanoemulsion was obtained in 30 min sonication having the mean droplet diameter of 3.8 nm. The antibacterial studies of nanoemulsion against Staphylococcus aureus by time kill analysis showed complete loss of viability within 15 min of interaction. Observations from scanning electron microscopy of treated bacterial cells confirmed the membrane damage compared to control bacteria. Furthermore, the wound healing potential and skin irritation activity of the formulated nanoemulsion in Wistar rats, suggested non-irritant and higher wound contraction rate with respect to control and neomycin treated rats. These results proposed that the formulated system could be favourable for topical application in pharmaceutical industries. © 2013 Elsevier B.V. All rights reserved.

Ultrasonics Sonochemistry

Ultrasonic emulsification of eucalyptus oil nanoemulsion: Antibacterial activity against Staphylococcus aureus and wound healing activity in Wistar rats