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

Department of Chemistry

The extensive use of semiconducting nanoparticles such as quantum dots in biomedical and industrial products can lead to their inadvertent release into the freshwater system. Natural exudates in the aquatic system comprising extracellular polymeric substance (EPS) and protein-rich metabolites can eventually adsorb onto the quantum dots (QDs) surface and form an eco-corona. The alterations in the physio-chemical and toxicological behavior of CdSe/ZnS QDs under the influence of eco-corona in the freshwater system have not been explored yet. In the present study, lake water medium conditioned with exudate secreted by Scenedesmus obliquus was utilized as an eco-corona forming matrix. The time-based evolution of the eco-corona on the differently charged CdSe/ZnS QDs was analyzed using transmission electron microscopy and dynamic light scattering. Aging of amine-QDs in algal exudate for 72 h showed enhanced aggregation (Mean Hydrodynamic Diameter- 1969 nm) as compared to carboxyl-QDs (1543 nm). Further, eco-coronation tends to impart an overall negative charge to the QDs. The fluorescence intensity of amine-QDs was quenched by 84% due to the accumulation of higher eco-corona. An integrative effect of surface charge and accumulated eco-corona layer influenced the Cd2+ ion leaching from the QDs. An enhancement in the algal cell viability treated with carboxyl - CdSe/ZnS (90%) and amine- CdSe/ZnS QDs (94%) aged for 72 h suggested that eco-corona can effectively mitigate the inherent toxicity of the QDs. The oxidative stress markers in the algal cells (LPO, SOD, and CAT) were in correlation with the cytotoxicity results. The algal photosynthetic efficiency depended on the deposition of eco-coronated QDs on the cell surface. Cellular uptake results indicated low Cd2+ concentration of nearly 13.9 and 11.5% for carboxyl- and amine- CdSe/ZnS QDs respectively. This suggests that eco-coronation directly influences the bioavailability of engineered nanoparticles. © 2020 Elsevier Ltd

World University root node

School of Advanced Sciences

Vellore Campus

Centre for Nanobiotechnology

Environmental Pollution

Mitigating the toxic effects of CdSe quantum dots towards freshwater alga Scenedesmus obliquus: Role of eco-corona

The global demand for improved living standards coupled with the rising emission of pollutant/hazardous gases which are detrimental to human life and the environment have led to the increasing need for the development of highly efficient and low-cost gas sensors; to detect, quantify and isolate the pollutant/hazardous gaseous species from their sources or environments. Herein, we report the synthesis, characterization, and gas sensing properties of low-cost, high-quality V2O5 thin films ultrasonically nebulized on quartz substrate at three different temperatures: 350 °C (V2O5-Qu-350), 400 °C (V2O5-Qu-400) and 450 °C (V2O5-Qu-450). Phase formation and purity were revealed by X-ray diffraction and confirmed by Raman measurements. Morphological investigation by SEM showed the highly porous nature of the thin films. We investigated the effect of deposition temperature on the gas sensing properties of synthesized V2O5 thin films. The V2O5-Qu-350, V2O5-Qu-400 and V2O5-Qu-450 thin films were used to fabricate the gas sensing devices. Their response towards various concentrations of ethanol, NO2, CO, and other volatile organic compounds (VOCs) like acetone, n-hexane and propan-2-ol at different operating temperatures were studied using an in-house built sensing setup. The chosen analytes are common industrial solvents or hazardous pollutants. The V2O5-Qu-350 thin films showed the highest response towards ethanol (88.1) and NO2 (809.4) at an optimized operating temperature of 280 °C. Further, the V2O5-Qu-350 thin films demonstrated high selectivity towards ethanol when subjected to CO and other VOCs like acetone, n-hexane and propan-2-ol. Our samples exhibited better performance than that of the reported V2O5-based gas sensors. © 2021 Elsevier B.V.

Sensors and Actuators, B: Chemical

Highly sensitive and selective ultrasonically nebulized V2O5 thin films towards ethanol and NO2 gas detection

Neglected tropical diseases (NTDs) as termed by WHO include twenty different infectious diseases that are caused by bacteria, viruses, and parasites. Among these NTDs, Chagas disease and leishmaniasis are reported to cause high mortality in humans and are further associated with the limitations of existing drugs like severe toxicity and drug resistance. The above hitches have rendered researchers to focus on developing alternatives and novel therapeutics for the treatment of these diseases. In the past decade, several target-based drugs have emerged, which focus on specific biochemical pathways of the causative parasites. For leishmaniasis, the targets such as nucleoside analogs, inhibitors targeting nucleoside phosphate kinases of the parasite’s purine salvage pathway, 20S proteasome of Leishmania, mitochondria, and the associated proteins are reviewed along with the chemical structures of potential drug candidates. Similarly, in case of therapeutics for Chagas disease, several target-based drug candidates targeting sterol biosynthetic pathway (C14-ademethylase), L-cysteine protease, heme peroxidation, mitochondria, farnesyl pyrophosphate, etc., which are vital and unique to the causative parasite are discussed. Moreover, the use of nano-based formulations towards the therapeutics of the above diseases is also discussed. © Copyright © 2021 J, M and Chanda.

Chemistry

Chennai Campus

Fulltext

Frontiers in Chemistry

An Overview on the Therapeutics of Neglected Infectious Diseases—Leishmaniasis and Chagas Diseases

The recent emergence of novel coronavirus (SARS-CoV-2) has been a major threat to human society, as the challenge of finding suitable drug or vaccine is not met till date. With increasing morbidity and mortality, the need for novel drug candidates is under great demand. The investigations are progressing towards COVID-19 therapeutics. Among the various strategies employed, the use of repurposed drugs is competing along with novel drug inventions. Based on the therapeutic significance, the chemical constituents from the extract of Tinospora cordifolia belonging to various classes like alkaloids, lignans, steroids and terpenoids are investigated as potential drug candidates for COVID-19. The inhibition potential of the proposed compounds against viral spike protein and human receptor ACE2 were evaluated by computational molecular modeling (Auto dock), along with their ADME/T properties. Prior to docking, the initial geometry of the compounds were optimized by Density functional theory (DFT) method employing B3LYP hybrid functional and 6–311 + + G (d,p) basis set. The results of molecular docking and ADME/T studies have revealed 6 constituents as potential drug candidates that can inhibit the binding of SARS-CoV-2 spike protein with the human receptor ACE2 protein. The narrowed down list of constituents from Tinospora cordifolia paved way for further tuning their ability to inhibit COVID-19 by modifying the chemical structures and by employing computational geometry optimization and docking methods. Graphic abstract: [Figure not available: see fulltext.] © 2021, Indian Virological Society.

VirusDisease

Computationally approached inhibition potential of Tinospora cordifolia towards COVID-19 targets

Quercetin being an essential flavonoid, controls the metal flow in our body, and is an important dietary component in many daily foodstuffs. In this study, quercetin (QCT) metal complexes are synthesized, and their stability has been investigated in different pH conditions. Further, the oxidized forms of quercetin in the processed food products (garlic pickle) and in non-processed food (garlic) are examined. The quercetin metal complexes (M-QCT) and their oxidized derivatives are characterized by using UV-vis, FT-IR, UPLC-DAD, GC-MS, and AAS. The disintegration of QCT and M-QCT complexes is monitored by RP-UPLC with diode array (RP-UPLC-PDA) detection in detecting the loss of major components. Moreover, the present project has checked the exposure of M-QCT (M = Mg, Zn) on the development/growth of zebrafish embryos. This study reveals that the Zn-QCT complex is more stable compare to std. QCT and Mg-QCT complex. Also, Zn-QCT is toxic to zebrafish embryos compared to std. QCT and Mg-QCT complex. The results of this study suggest the usage of M-QCT complexes in the processed foodstuffs instead of pure QCT. © 2021, AMG Transcend Association. All rights reserved.

Biointerface Research in Applied Chemistry

Stability comparison of quercetin and its metal complexes and their biological activity

Multidentate copper metal complexes have been in the limelight in the area of DNA interaction studies exhibiting intercalation, groove binding and cross linking modes. Design of metal complex based on the versatile ligands decides their mode of DNA binding behavior. Based on this, a tetradentate Copper (II) complex, [Cu(L)(4,4’-bpy)], is synthesized using ONO hydrazone ligand and ancillary ligand, 4,4’-bipyridine. It is characterized by physico-chemical and UV-Visible, FTIR, Mass and EPR spectroscopic techniques. The binding pattern of the characterized complex with DNA has been assessed by UV absorption and fluorescence spectral titrations as well as viscosity studies and it has exhibited peculiar threading intercalation. The binding constant, Kb value of the synthesized complex was found to be (4.38 ± 0.09) × 104 M−1, greater than that of the hydrazone ligand (Kb = 2.29 × 104 M−1) and lesser than the classical intercalator ethidium bromide - EtBr (Kb = 107). The fluorescence quenching assays in the presence of ethidium bromide and viscometric studies show threading intercalative mode of binding of the complex to the DNA base pairs. Molecular docking studies further supports such a binding pattern with the bipyridine ring of the complex intercalating with deoxycytosine nucleobase of DNA. ADME (Absorption, Distribution, Metabolism and Excretion) parameters of the complex and ligand were predicted to get an idea of drug likeliness and to correlate the structural properties with semi DNA intercalative pattern of the same. © 2021 Taylor & Francis Group, LLC.

Nucleosides, Nucleotides and Nucleic Acids

Peculiar DNA partial threading intercalative ability of tetradentate copper complex based on ONO hydrazone backbone and an ancillary ligand

In this investigation, novel g-C3N4/Cu3TiO4 (CNCT) nanocomposite was synthesized by using a simple thermal condensation method. The synthesized CNCT nanocomposite was characterized by X-ray Diffraction, Transmission electron microscopy, Atomic force microscopy, Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, Photoluminescence, Brunauer–Emmett–Telle, Zeta Potential, and Thermogravimetric analysis. The study revealed that the catalysts prepared have high crystalline nature, optical light-absorbing property, high surface area, and stability. The CNCT- nanocomposite was found to be an extraordinary visible light absorbing catalyst for the synthesis of quinoxaline and quinazolinone derivatives, which have important benefits in a variety of drug applications. Quinoxaline and quinazolinones were prepared from anthranilamide, diamines, benzil, and corresponding aldehydes under Ultrasonic/visible light-medium with a notable amount of g-C3N4/Cu3TiO4. The results exhibit good and excellent yields of product derivatives at mild conditions under Ultrasonic/visible light-medium. Ultrasounds always clean the active site catalyst, promoting activity and reusability. Most notably, with preserved reactivities, this heterogeneous g-C3N4/Cu3TiO4 composite can be used atleast 5 times. Furthermore, we examined the reusability of the catalyst under Ultrasonication coupled with Visible light and in the absence of an Ultrasonication medium. Finally, advantages of the method are non-conventional approach, green solvent, reduced reaction duration, mild condition, and reusable catalyst. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.

Research on Chemical Intermediates

Ultrasound/visible light-mediated synthesis of N-heterocycles using g-C3N4/Cu3TiO4 as sonophotocatalyst

The current investigation aims to replace the synthetic starting materials with biowaste to synthesize and explore three different silicate bioceramics. Pure silica from rice husk was extracted by decomposition of rice husk in muffle furnace followed by alkali treatment and acid precipitation. Raw eggshell and extracted silica were utilized for the preparation of wollastonite, diopside and forsterite by the solid-state method. The TG-DSC analysis shows that the crystallization temperature of wollastonite, diopside and forsterite was found to be 883 °C, 870 °C and 980 °C, respectively. The phase purity of wollastonite was attained at 1100 °C whereas diopside and forsterite were composed of secondary phases even after calcination at 1250 °C and 1300 °C respectively. All three materials behaved differently when exposed to the physiological environment, as wollastonite exhibited remarkable apatite deposition within 3 days whereas a distinct apatite phase was noticed on the surface of diopside after 2 weeks and forsterite shows the formation of apatite phase after five weeks of immersion. The rapid dissolution of Mg2+ ion from forsterite lowered the leaching of silicate ions into the simulated body fluid leading to poor apatite deposition over its surface. Chemical composition was found to plays a key role in the biomineralization ability of these bioceramics. Hemolysis and Lactate Dehydrogenase (LDH) release assays were performed to evaluate the hemocompatibility of silicate ceramics cultured at different concentrations (62.5, 125, and 250 μg/mL) with red blood cells and mononuclear leucocytes (MLs) of mice. The hemolytic activity of all the tested bioceramics was insignificant (less than 1%). The interaction between diopside and mouse multipotent mesenchymal stromal cells (MMSCs) caused a negligible increase in the number of apoptosis-associated Annexin V-binding cells whereas forsterite and wollastonite induced an increase in the number of the apoptotic cells only at the concentration of 250 μg/mL. The LDH assay did not show statistically significant changes in the proliferation of MMSCs after treatment with the bioceramics at the tested concentrations when compared to control (p &gt; 0.05). This finding showed that the death of a part of cells during the first 24 h of incubation did not prevent the proliferation of MMSCs incubated with diopside, forsterite and wollastonite for 72 h. © 2020 Elsevier B.V.

Materials Science and Engineering C

Biomineralization, dissolution and cellular studies of silicate bioceramics prepared from eggshell and rice husk

Journal of Sol-Gel Science and Technology

Antibacterial wollastonite supported excellent proliferation and osteogenic differentiation of human bone marrow derived mesenchymal stromal cells

This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial to overcome the challenges associated with calcium phosphate bioceramics. The influence of chemical composition on synthesis temperature, bioactivity, antibacterial activity and mechanical stability of least explored calcium silicate bioceramics was studied. The current study also investigates the biomedical applications of rankinite (Ca3Si2O7) for the first time. Sol-gel combustion method was employed for their preparation using citric acid as a fuel. Differential thermal analysis indicated that the crystallization of larnite and rankinite occurred at 795 °C and 1000 °C respectively. The transformation of secondary phases into the desired product was confirmed by XRD and FT-IR. TEM micrographs showed the particle size of larnite in the range of 100–200 nm. The surface of the samples was entirely covered by the dominant apatite phase within one week of immersion. Moreover, the compressive strength of larnite and rankinite was found to be 143 MPa and 233 MPa even after 28 days of soaking in SBF. Both samples prevented the growth of clinical pathogens at a concentration of 2 mg/mL. Larnite and rankinite supported the adhesion, proliferation and osteogenic differentiation of hBMSCs. The variation in chemical composition was found to influence the properties of larnite and rankinite. The results observed in this work signify that these materials not only exhibit faster biomineralization ability, excellent cytocompatibility but also enhanced mechanical stability and antibacterial properties. © 2020 Elsevier B.V.