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

There has been a significant increased concern of the impact of the toxicity of multiple contaminants in the marine environment. Thus, this study was aimed at determining whether the interaction between nano-TiO2 and Cr(VI) would modulate their toxic effects with the marine crustacean, Artemia salina. Nano-TiO2 agglomerated in artificial sea water (ASW) and readily formed micron-sized particles that settled down in the medium. The addition of Cr(VI) to nano-TiO2 aggravated their agglomeration through sorption of Cr(VI) onto nano-TiO2. This was reflected by a decrease in the residual concentration of Cr in the suspension. Acute toxicity tests performed using pristine nano-TiO2 (0.25, 0.5, 1, 2, and 4 mg/L) and Cr(VI) (0.125, 0.25, 0.5, and 1 mg/L) displayed a concentration dependent rise in the mortality of Artemia salina. To examine the effects of mixtures of nano-TiO2 and Cr(VI) on Artemia salina, two groups of experiments were designed. The former group studied the toxic effect of nano-TiO2 (0.5, 1, 2, and 4 mg/L) with a fixed concentration (0.125 mg/L) of Cr(VI). While the latter group studied the toxicity of Cr(VI) (0.25, 0.5, and 1 mg/L) with a fixed concentration (0.25 mg/L) of nano-TiO2. The toxic effects of nano-TiO2 was not significantly reduced at a fixed concentration of Cr(VI) but in contrast, a significant reduction in the Cr(VI) toxicity by fixed concentration of nano-TiO2 was observed. Toxicity data was well supported by an independent action model that proved the mode of action between nano-TiO2 and Cr(VI) to be antagonistic. Furthermore, ROS generation and measurement of antioxidant enzyme activities were also in line with toxicity results. From this study, the modification of Cr(VI) toxicity at fixed concentration of nano-TiO2 could have a huge impact on the reduction in Cr(VI) toxicity across trophic levels. © 2020 Elsevier B.V.

World University root node

Vellore Campus

Aquatic Toxicology

Combined effects of nano-TiO2 and hexavalent chromium towards marine crustacean Artemia salina

Here, in this study, we strategically utilized low-energy mediated epitaxial deposition of Au0 atoms reduced by gallic acid over preformed gold nanorods (GNRs) seeds. It can be suggested that GNRs seed/Au3+ ratio influences the directional attachment of Au0 atoms to the GNRs. Alteration in the thickness of the GNRs upon deposition of Au0 in presence micromolar levels of antioxidant reduces the aspect ratio of the nanorods. Change in the aspect ratio altogether induces a blue-shift in the longitudinal surface plasmon resonance (LSPR) of the GNRs from the NIR region of the spectrum to the shorter wavelength. TEM imaging, DLS and zeta potential analyses confirms the morphological and surface-charge alterations after interaction with antioxidant. Based on the relation between blue-shift of the LSPR band and the concentration of gallic acid, the sensing platform achieves a linear detectable range of 1.25–35 μM with detection limit as low as 90 nM and the limit of quantification as 300 nM. The method has high selectivity against tested interferents and was found to be reproducible. The potential application of the developed sensor was validated by quantifying gallic acid in commercially available apple juice. High recovery (99.46–100.4%) was obtained, suggesting that the established assay which is reliable and facile can be successfully used for gallic acid detection real food samples. The developed method of tuning the aspect ratio of nanomaterial can be further extended for detection other anti-oxidant molecules.

VIT Unitversity

Department of Chemistry

School of Advanced Sciences

Fulltext

Materials Chemistry and Physics

Development of thickness-tunable gold nanorods for anti-oxidant detection

Creation of interfaces with a prudent design for the immobilization of biomolecules is substantial in the construction of biosensors for real-time monitoring. Herein, an adept biosensing interface was developed using a nanoconjugated matrix and has been employed toward the electrochemical determination of hydrogen peroxide (H2O2). The anionic gold nanoparticle (AuNP) was electrostatically tethered to cationic redox ionic liquid (IL), to which the horseradish peroxidase (HRP) enzyme was covalently immobilized to form a nanobioconjugate. The anthracene-substituted, aldehyde-functionalized redox IL (CHO-AIL) was judiciously designed with the (i) imidazolium cation for electrostatic interaction with AuNPs, (ii) anthracene moiety to mediate the electron transfer, and (iii) free aldehydic group for covalent bonding with a free amine group of the enzyme. Thus, the water-soluble HRP is effectively bonded to the CHO-AIL on a glassy carbon electrode (GCE) via imine bond formation, which resulted in the formation of the HRP-CHO-AIL/GCE. Electrochemical investigations on the HRP-CHO-AIL/GCE reveal highly stable and distinct redox peaks for the anthracene/anthracenium couple at a formal potential (E°′) of-0.47 V. Electrostatic tethering of anionic AuNPs to the HRP-CHO-AIL promotes the electron transfer process in the HRP-CHO-AIL/AuNPs/GCE, as observed by the reduction in the formal potential to-0.42 V along with the enhancement in peak currents. The HRP-CHO-AIL/AuNPs/GCE has been explored toward the electrocatalytic detection of H2O2, and the modified electrode demonstrated a linear response toward H2O2 in the concentration range of 0.02-2.77 mM with a detection limit of 3.7 μM. The developed biosensor ascertained predominant selectivity and sensitivity in addition to remarkable stability and reproducibility, corroborating the suitableness of the platform for the effectual biosensing of H2O2. The eminent performance realized with our biosensor setup is ascribed to the multifunctional efficacy of this newly designed nanobioconjugate. © 2020 American Chemical Society.

ACS Biomaterials Science and Engineering

Gold Nanoparticle-Redox Ionic Liquid based Nanoconjugated Matrix as a Novel Multifunctional Biosensing Interface

The current work investigated the potential of Tetracycline (TC) removal from aqueous solutions using Fe/Pd nanoparticles coated over sand by in situ process (IS-Fe/Pd). The developed IS-Fe/Pd was then characterized using XRD, SEM, and EDAX. In batch studies, optimum TC removal (99.78 ± 0.05 %) was attained by initial TC concentration: 20 μg/mL; IS-Fe/Pd weight: 1000 mg; and interaction time: 180 min. The underlying TC removal mechanism was studied by performing a thorough characterization of IS-Fe/Pd and TC solution during the removal process. The structural modifications in IS-Fe/Pd were characterized using XRD, FTIR, SEM, and EDAX, while the chemical variations of the TC solution were studied through TOC, ORP, and LCMS measurements. A combination of degradation and adsorption by IS-Fe/Pd nanoparticle-coated sand was responsible for TC removal from aqueous medium. Also, the cell viability assessment using the bacteria, Bacillus and Pseudomonas, and algae Chlorella sp. revealed that the toxicity of TC has substantially reduced after treatment with IS-Fe/Pd nanoparticle-coated sand. Further, the column study evaluated the impacts of varying bed height, flow rate, and initial TC concentration. At the optimized condition (bed height: 10 cm; flow rate: 1 mL/min; initial TC concentration: 20 μg/mL), the removal capacity was 433 ± 13 μg/mg in column reactors. In the case of TC-spiked natural water systems, 350 ± 18 μg/mg and 395 ± 15 μg/mg capacity was noted for lake and tap water, respectively. © 2020 Elsevier Ltd

Department of Environmental and Water Resources Engineering

School of Civil Engineering

Journal of Water Process Engineering

In-situ coating of Fe/Pd nanoparticles on sand and its application for removal of tetracycline from aqueous solution

Fluorescence microscopy is one of the important instruments used in research and clinical laboratories on an everyday basis due to its wide range of applications ranging from a diagnostic tool to a molecular imaging device. However, the high cost, complex instrumentation, and requirement of sophisticated facilities limit its availability to school and college students, especially in developing and underdeveloped countries. In this work, we report the design and development of a slide-like portable total internal reflection fluorescence (TIRF) adapter, which can be integrated easily with Foldscope (a paper microscope) to observe and capture the fluorescence images using any smartphone. The adapter consists of a battery-powered LED (light source), a small piece of multimode optical fiber, a slide-like 3-D printed waveguide platform to hold the optical fiber and light emitting diode (LED) at an appropriate position. The potential of the adaptor is validated by capturing the fluorescence images of two most commonly used dyes i.e. fluorescein isothiocyanate (FITC) and rhodamine-B, after being immobilized on amine-functionalized optical fiber probe. Further, this adaptor is successfully used to demonstrate (i) Förster resonance energy transfer phenomenon by employing FITC dye as donor and gold nanoparticles as quencher moiety and (ii) fluorescence bioassay by observing antigen-antibody interactions using human immunoglobulin G as the receptor and FITC-tagged goat anti-human immunoglobulin G as analyte. The inexpensive, portable and user-friendly TIRF adapter is a potential alternative to conventionally used fluorescence microscopes, especially for the school and college students and in resource-constrained clinical laboratories. © 2019 IEEE.

IEEE Sensors Journal

Total Internal Reflection Fluorescence Foldscope Adapter: Design, Fabrication and Applications

Chemosphere

Nano-scale zero valent iron modulates Fe/Cd transporters and immobilizes soil Cd for production of Cd free rice

Biotechnology and Bioengineering

Mechanism of the oxidative stress-mediated increase in lipid accumulation by the bacterium, R. opacus PD630: Experimental analysis and genome-scale metabolic modeling

A critical literature survey on marine ecotoxicology reveals a lack of comprehensive studies to assess the impact of microplastics on the toxicity of engineered nanomaterials at environmentally relevant doses. Though ZnO and microplastics both are well known to be marine pollutants, the combined toxicity of ZnO particles with plain polystyrene (PS) microplastics are yet to be studied. Preliminary characterization of ZnO particles included examining particle size, morphology, and surface area. The amount of nominal and dissolved ions in the suspensions containing nano-sized ZnO particles was determined. The toxicity of bulk and nano-sized ZnO particles in combination with plain PS microplastics at low concentration (1 mg/ L) was assessed towards marine algae Dunaliella salina at three exposure concentrations 1.22, 12.28 and 122.88 μM under UV-A and dark exposure conditions. As expected, a dose-dependent increment in the toxicity, ROS (extracellular & intracellular) generation and lipid peroxidation were noted for both bulk and nano-sized ZnO particles. The harmful effects of bulk and nano-sized ZnO particles were considerably reduced in the presence of plain PS microplastics. This study opens up new dimensions regarding the positive impact of microplastics at low concentration, where they lessen the toxic effects of co-pollutants in the marine ecosystem. © 2020 Elsevier Ltd.

Journal of Environmental Chemical Engineering

Plain polystyrene microplastics reduce the toxic effects of ZnO particles on marine microalgae Dunaliella salina.

Continued use of P25 TiO2 NPs in several fields necessitates their toxicity evaluation towards the ecosystem. Considering the high photocatalytic activity of TiO2 NPs, they were selected in the current study. The photocatalytic potential and toxicity of NPs on freshwater algae Chlorella sp. were compared upon UVA pre-irradiation and UVB pre-irradiation. Low concentrations (1.56, 3.13, and 6.26 μM) of NPs used for the study correlate well with the available environmental concentrations. The mean hydrodynamic diameter (MHD) for UVB pre-irradiated NPs (159.34 ± 0.68 nm) was the least when compared with UVA pre-irradiated (179.99 ± 0.85 nm) and non-irradiated NPs (220.04 ± 6.05 nm). This decrease in MHD denoted lesser agglomeration of NPs upon UVB pre-irradiation. For all the tested concentrations, the cell viability was less for UVB pre-irradiated NP-treated algae when compared to UVA pre-irradiated NP-treated algae (p < 0.001). Extracellular ROS generation was significantly higher for UVB pre-irradiated NPs (p < 0.001) as compared to UVA pre-irradiation. The enhanced toxicity of UVB pre-irradiated NPs was accompanied by increased generation of intracellular ROS, which in turn increased the SOD, CAT, and APX enzyme activities. This study concludes that UVB pre-irradiation of P25 TiO2 NPs caused more harm to freshwater algae through oxidative stress when compared to UVA pre-irradiation. © 2020 Elsevier Ltd.

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

UVB pre-irradiation of titanium dioxide nanoparticles is more detrimental to freshwater algae than UVA pre-irradiation

The production of different size and shape silver nanoparticles (AgNPs) has increased considerably in recent years due to several commercial and biological applications. Here, rod-shaped AgNPs (SNRs) were prepared using the microwaveassisted method and characterised by ultraviolet-visible spectroscopy, and transmission electron microscopy analysis. The present study aims to investigate the cyto-genotoxic effect of various concentrations (5, 10, and 15 μM) of SNRs using Allium cepa model. As a result, concentration-dependent cyto-genotoxic effect of SNRs was observed through a decrease in the mitotic index, and an increase in the chromosomal aberrations such as chromosome break, disturbed metaphase, and anaphase bridge. To check the impact of Ag+ ions, 15 μM silver nitrate (AgNO3) was prepared and tested in all the assays. Furthermore, cell viability and different reactive oxygen species assays were performed to test the cytotoxicity evaluation of SNRs. The authors found that in all the tested assays, SNRs at high concentrations (15 μM) and AgNO3 (15 μM) were observed to cause maximal damage to the roots. Therefore, the current study implies that the cytotoxicity and genotoxicity of SNRs were dependent on the concentration of SNRs. © 2019 The Institution of Engineering and Technology.