e) 2020-Scopus Open Access (PDF)
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Item SYNTHESIS, CHARACTERIZATION, THERMAL, THEORETICAL AND ANTIMICROBIAL STUDIES OF SCHIFF BASE LIGAND AND ITS CO(II) AND CU(II) COMPLEXES (Article)(Serbian Chemical Society, 2020) Palaniswamy, Radha Venkittapuram; Dhandapani, Mahalakshmi; Suyambulingam, Jonekirubavathy; Subramanian, ChitraA Schiff base ligand L was synthesized by condensation of 1,2-diaminoethane with creatinine. The reaction of the ligand with metal chloride salt gives Co(II) and Cu(II) complexes. The synthesized ligand and its metal complexes were characterized by elemental analysis, FT-IR, NMR, UV-Vis, conductivity and magnetic susceptibility measurements as well as thermal analyses. Based on spectral data, tetrahedral geometries have been proposed for the Co(II) and Cu(II) complexes. The molar conductivity data show that the complexes are non-electrolytic in nature. In DFT studies, the geometry of the Schiff base ligand and its Co(II) and Cu(II) complexes were fully optimized using the B3LYP functional together with 6-31g(d,p) and LANL2DZ basis sets. The ligand and its metal complexes were tested against four bacterial species and two fungal species. The results revealed that the metal complexes are more potent against the microbes than the parent ligand.Item DEXTRAN SULFATE STABILIZED SILVER NANOPARTICLE: NEXT GENERATION EFFICIENT THERAPY FOR CANCER (Article)(Innovare Academic Sciences, 2020-01-15) Sharmila, Chandran; Thilagavathy, Ponnusamy; Dinesh, Bheeman; Ranjith Kumar, RajamaniObjective: Synthesize silver nanoparticles using a green synthesis approach and encapsulate silver nanoparticles with a naturally occurring polymer, particularly of an-hydroglucose type, like dextran sulfate sodium salt and to study its anticancer activity.Methods: Green synthesis approach is been employed in the synthesis of silver nanoparticles using Psidium guajava leaf extract. The nanoparticles were then encapsulated with dextran sulfate biopolymer and the nanoparticles were subjected to different characterization techniques. The structure of the synthesized nanoparticles was analyzed using X-ray diffraction analysis, the presence of different functional groups was analyzed by FTIR studies. Size and morphology of the prepared nanoparticles were investigated using FESEM analysis. Anticancer activity of the synthesized nanoparticles was tested against the MCF-cell line. Results: The XRD analysis shows the crystalline nature of the synthesized nanoparticles. The stretching and vibrating modes of different functional groups were confirmed by FTIR result. The SEM image confirmed the presence of spherical shaped nanoparticles and the TEM image confirmed the average size of the particles to be around 24 nm. The Ag-DS NPs showed 91% cell inhibition for the concentration of 100 μg/ml, indicating the cytotoxicity of the nanoparticles against MCF-7 cell line.Conclusion: Dextran sulfate stabilized silver nanoparticles show potent anticancer activity against MCF-7 cell lineItem INFLUENCE OF GA2O3, CUGA2O4 AND CU4O3 PHASES ON THE SODIUM-ION STORAGE BEHAVIOUR OF CUO AND ITS GALLIUM COMPOSITES (Article)(Royal Society of Chemistry, 2020-02-14) Rekha, Pilliadugula; Chandrasekaran, Nithya; Gopala Krishnan, NCuO and its gallium composites with various compositions are successfully fabricated by using a hydrothermal technique followed by calcination at 900 °C. The added Ga precursors formed oxides in the composites, such as Ga2O3, CuGa2O4 and Cu4O3, as confirmed through the X-ray diffraction patterns as well as the HRTEM and SAED patterns. Further HRTEM analysis also confirmed that Cu4O3 and CuGa2O4 phases reside on the surface of CuO in the composites with a CuO : Ga ratio of 90 : 10. The contents of various oxide phases varied when we increased the amount of Ga in the CuO composites. Changing the ratios of CuO and Ga precursors in the composites is quite effective in tailoring the sodium-ion storage behaviour of CuO. The resultant CuO/Ga composites exhibit remarkable electrochemical performance for sodium-ion batteries in terms of capacity, rate capability and cycling performance. The composite containing 90% CuO and 10% Cu/Ga oxides delivers the highest charge capacity of 661 mA h g−1 at a current density of 0.07 A g−1 with a capacity retention of 73.1% even after 500 cycles. The structure and morphology of the composite (90% CuO and 10% Cu/Ga oxides) was successfully retained after 500 cycles, which was confirmed through ex situ XRD, SEM and HRTEM analyses. The composite also exhibited remarkable rate capability in which it delivered 96 mA h g−1 even at a high current density of 6.6 A g−1. The enhanced electrochemical performances of CuO and its gallium composites are attributed to the presence of Cu4O3 and CuGa2O4 phases. The Cu4O3 phase is actively involved in the redox reaction and the CuGa2O4 phase stabilizes the CuO phase and buffers the volume expansion of CuO during cycling. The present approach eplores great opportunities for improving the electrochemical performance of oxide based anode materials for sodium-ion batteries.Item CU2FESNS4 NANOPARTICLES: POTENTIAL PHOTOVOLTAIC ABSORPTION MATERIALS FOR SOLAR CELL APPLICATION (Article)(IOP Publishing Ltd, 2020-03-16) Deepika, R; Meena, PQuaternary semiconductor Cu2FeSnS4 (CFTS) nanoparticle powder have been prepared by a simple chemical technique. The synthesized CFTS nanoparticles have been characterized via powder XRD analysis, Raman spectra, FE-SEM-EDS, UV-Visible absorption spectroscopy, thermal analysis and electrochemical characterization. Powder XRD and Raman spectroscopy confirm the phase and structure of the prepared nanoparticles. The optical absorption studies reveal that the CFTS nanoparticles have a direct optimal band gap in the range from 1.32 to 1.5 eV, which indicates that these nanoparticles are potential absorber materials for thin-film photovoltaic application. The synthesized CFTS nanoparticles were transformed to the ink form and the obtained nanoparticle ink coated on a FTO conducting substrate (surface resistivity-13 Ω sq−1). The catalytic activity of the substrate was analyzed by electrochemical impedance spectroscopy (EIS) and cyclic voltammogram (CV) curves. The appropriate optical band gap and stable electrical properties indicate that Cu2FeSnS4 Nanoparticles are potential materials for thin-film photovoltaic application.Item 3D NANOMANIPULATION: DESIGN AND APPLICATIONS OF FUNCTIONAL NANOSTRUCTURED BIO-MATERIALS (Conference Paper)(IOP Publishing Ltd, 2020) Lega, P V; Orlov, A P; Frolov, A V; Subramani, R; Irzhak, A V; Koledov, V V; Smolovich, A.M; Shelyakov, A.VRecent progress in the development of the new functional materials opens up exciting possibilities for designing reconfigurable micro- and nano-structures and for operating mechanical nanotools which are controlled by external fields or heat. The nanotools such as nanotweezers with an active layer thickness of about several tenths of nm, and whose overall size is of the order of 1 μm can be applied to different micro- and nanoobjects. The present report gives an overview of the application of mechanical nanotools in 3D nanomanipulation of bio-nano objects such as micro biofibers DNA etc. The future prospects of mechanical bottom up nanomanipulation for biomedical technology, food technology are discussed.Item POLYMER-ASSISTED SYNTHESIS AND APPLICATIONS OF HYDROXYAPATITE (HAP) ANCHORED NITROGEN-DOPED 3D GRAPHENE FOAM-BASED NANOSTRUCTURED CERAMIC FRAMEWORK (Article)(Royal Society of Chemistry, 2020-05-11) Murugesan, Manoj; Jinbo, Song; Wenjian, Zhu; Hu, Zhou; Junhao, Zhang; Palaniappan, Meena; Aihua, YuanIn the present work, a hydroxyapatite anchored nitrogen-doped three-dimensional graphene (HAp-N3DG) skeletal network (foam) based nanostructured ceramic framework (CF) was developed through a polymer-assisted solvothermal route. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) studies reveal that the nano sized 0D HAp particles are anchored on the N3DG skeletal network with an average size of less than 50 nm. EDX and X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Ca, P, O, N, and C. In addition, XPS analysis reveals the existence of N–C bonds in the prepared sample. The X-ray diffraction (XRD) patterns indicate the presence of hexagonal phase hydroxyapatite and the calculated average crystallite size was found to be 12 nm. The developed HAp-N3DG foam based nanostructured CF was found to have a mesoporous structure and the measured specific surface area (SSA) and the mean pore diameter were found to be 64.73 m2 g−1 and 23.6 nm, respectively. Electrochemical analysis shows that HAp anchored on nitrogen-doped 3D graphene foam based nanostructured CF has moderate electrochemical activity towards lithium ion charge/discharge. In addition, the prepared material showed adsorption activity values of 204.89 mg g−1 and 243.89 mg g−1 for the volatile organic compounds (VOCs) benzene and toluene, respectively. The present findings suggest that the newly developed HAp anchored nitrogen-doped 3DG (HAp-N3DG) skeletal network (foam) based nanostructured CF material can be used in energy devices and in the removal of volatile organic compounds. Moreover, the present study initiates a new kind of approach in energy device (lithium ion battery-LIB) research and in the removal of VOCs.Item SYNTHESIS, CHARACTERIZATION, BIOLOGICAL AND PHOTOLUMINESCENCE STUDY OF CO(II) COMPLEXES OF FUSED HETEROCYCLIC RING SYSTEMS (Article)(Indian Journal of Pharmaceutical Education and Research, 2020-08) Suyambulingam, Jone Kirubavathy; Subramanian, ChitraTo synthesize and characterize the transition metal complexes of fused heteroccylic ring systems. Background: Many of the fused ring heterocyclic compounds were found to be biologically active in the literature like anti-microbial, anti-cancer, anti-inflammatory, anti-oxidant and so on. The present work focus on the synthesis of the biologically active compounds. Materials and Methods: Synthesis of the ligands and the complexes are done using the standard procedures in earlier reports. Melting points were found using open glass capillaries on a Raaga melting point apparatus and are uncorrected. The percentage of C, H, N , infra-red and UV-Visible spectra of the compounds were recorded using Elementar Vario EL III CHN analyser, Shimadzu spectrophotometer (4000-400 cm-1) and Elico SL 159 UV-Vis spectrophotometer respectively. The antimicrobial activity of the compounds was carried out by well diffusion method. The anticancer activity of the compounds were carried out for the MCF-7 cell line (breast Cancer) using MTT assay. Discussion and Conclusion: Structural elucidation of newly synthesized Co(II) metal complexes of fused heterocyclic ring systems were done using various spectral techniques like FT-IR, 1H-NMR, Electronic and TGA-DTA studies. The anti-microbial activity of the prepared complexes and the DNA Cleavage studies were screened for various test pathogens and explained. The photoluminescence property of the fused heterocyclic ligand and their complexes were studied and compared. Fluorescence enhancement is observed in these complexes which is contradictory to the normal Fluorescence quenching phenomena by added organic derivatives, paved way for photochemical applications.Item THE INFLUENCE OF SWELLING ON ELASTIC PROPERTIES OF POLYACRYLAMIDE HYDROGELS (Article)(Frontiers in Materials, 2020-07-23) Ramesh, Subramani; Alicia, Izquierdo-Alvarez; Pinaki, Bhattacharya; Mathieu, Meerts; Paula, Moldenaers; Herman, Ramon; Hans Van, OosterwyckPolyacrylamide (PAM) hydrogels are commonly used as substrates for cell mechanical and mechanobiological studies because of their tunable stiffness and ease of handling. The dependence of bulk rheological and local elastic properties (assessed by Atomic Force Microscopy, or AFM) of PAM hydrogels on its composition and polymerization temperature has been extensively studied. PAM hydrogels swell when immersed in media, but the influence of swelling on local elastic properties is poorly characterized. Direct measurements of the effect of swelling on PAM elastic properties are scarce. We report here, for the first time, the direct measurements of volumetric swelling and local elastic properties of PAM gels throughout the post-polymerization swelling process until equilibrium. First, local and global elastic properties (measured by rheology), were obtained during polymerization in the absence of swelling, and showed good agreement with each other. Four PAM hydrogel compositions were characterized thus, with corresponding storage shear moduli (as measured immediately after polymerization) of 4,530 Pa (termed stiffest), 2,900 Pa (stiff), 538 Pa (soft), and 260 Pa (softest). Next, all compositions were subjected to swelling in phosphate buffered saline. Swelling ratios and local elastic moduli were measured at 0, 3, 6, 9, 12, and 24 h post-polymerization for the soft and softest compositions, and once daily till 6 days post-polymerization for all four compositions. For the stiffest and stiff gels, swelling ratio, and local elastic modulus changed negligibly with time, while for the soft and softest gels, substantial changes between Day 0 and Day 1 were found for both swelling ratio (increased by 21.6 and 133%, respectively), and local elastic modulus decreased (by 33.7 and 33.3%, respectively), substantially. Experimental data were analyzed by a model that combined ideal elastomer mechanics and poroelastic swelling kinetics model. Model predictions confirmed the validity of present measurements with respect to past studies where swelling and elastic properties were not measured simultaneously. The present study underlines the important effect swelling can have on PAM elastic properties and provides detailed quantitative data to guide the duration taken to reach equilibrium—a useful information for cell mechanics experiments. In addition, the simultaneous measurements of swelling and local elastic moduli provide novel data for the validation of theoretical models.Item TOWARDS MIMICKING THE FETAL LIVER NICHE: THE INFLUENCE OF ELASTICITY AND OXYGEN TENSION ON HEMATOPOIETIC STEM/PROGENITOR CELLS CULTURED IN 3D FIBRIN HYDROGELS (Article)(International Journal of Molecular Sciences, 2020-09-02) Christian, Garcia-Abrego; Samantha, Zaunz; Burak, Toprakhisar; Ramesh, Subramani; Olivier, Deschaume; Stijn, Jooken; Manmohan, Bajaj; Herman, Ramon; Catherine, Verfaillie; Carmen, Bartic; Jennifer, PattersonHematopoietic stem/progenitor cells (HSPCs) are responsible for the generation of blood cells throughout life. It is believed that, in addition to soluble cytokines and niche cells, biophysical cues like elasticity and oxygen tension are responsible for the orchestration of stem cell fate. Althoughseveral studies have examined the effects of bone marrow (BM) niche elasticity on HSPC behavior, no study has yet investigated the effects of the elasticity of other niche sites like the fetal liver (FL), where HSPCs expand more extensively. In this study, we evaluated the effect of matrix stiffness values similar to those of the FL on BM-derived HSPC expansion. We first characterized the elastic modulus of murine FL tissue at embryonic day E14.5. Fibrin hydrogels with similar stiffness values as the FL (soft hydrogels) were compared with stiffer fibrin hydrogels (hard hydrogels) and with suspension culture. We evaluated the expansion of total nucleated cells (TNCs), Lin−/cKit+ cells, HSPCs (Lin−/Sca+/cKit+ (LSK) cells), and hematopoietic stem cells (HSCs: LSK- Signaling Lymphocyte Activated Molecule (LSK-SLAM) cells) when cultured in 5% O2 (hypoxia) or in normoxia. After 10 days, there was a significant expansion of TNCs and LSK cells in all culture conditions at both levels of oxygen tension. LSK cells expanded more in suspension culture than in both fibrin hydrogels, whereas TNCs expanded more in suspension culture and in soft hydrogels than in hard hydrogels, particularly in normoxia. The number of LSK-SLAM cells was maintained in suspension culture and in the soft hydrogels but not in the hard hydrogels. Our results indicate that both suspension culture and fibrin hydrogels allow for the expansion of HSPCs and more differentiated progeny whereas stiff environments may compromise LSK-SLAM cell expansion. This suggests that further research using softer hydrogels with stiffness values closer to the FL niche is warranted.Item UTILIZATION OF BIOWASTE AS AN ECO-FRIENDLY BIODEGRADABLE CORROSION INHIBITOR FOR MILD STEEL IN 1 MOL/L HCL SOLUTION (Article)(Elsevier, 2020-12) Venkatesan, Hemapriya; Mayakrishnan, Prabakaran; Subramanian, Chitra; Manoharan, Swathika; Seung-Hyun, Kim; Ill-Min, ChungThis report focuses on the application of a biodegradable biowaste [human hair-(HHR)], to produce a mild steel corrosion inhibitor. The performance of HHR extract in inhibiting metallic corrosion in 1 mol/L HCl was investigated. The analysis of the metal corrosion behavior using electrochemical and weight loss techniques revealed that HHR exhibits an efficient corrosion-mitigating effect via adsorption on the metal surface following a Langmuir isotherm. Tafel-plot results revealed the mixed-mode corrosion protection behavior of HHR. Surface analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy provided evidence for the precipitation of a protective HHR film on the metal surface.