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Palem RR, Bathula C, Shimoga G, Lee SH, Ghfar AA, Sekar S, Kim HS, Seo YS, Rabani I. Fabrication of Ru loaded MgB 2 with guar gum hybrid for photocatalytic degradation of crystal violet. Int J Biol Macromol 2023; 253:126948. [PMID: 37722634 DOI: 10.1016/j.ijbiomac.2023.126948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 09/04/2023] [Accepted: 09/08/2023] [Indexed: 09/20/2023]
Abstract
Today, dyes/pigment-based materials are confronting a serious issue in harming marine ecology. Annihilate these serious water pollutants using photoactive 2D nanohybrid catalysts showed promising comparativeness over available photocatalysts. In the present work, a facile route to decorate Ruthenium (Ru) on 2D MgB2 flower-like nanostructures was developed via ecofriendly guar gum biopolymer substantial template (MgB2/GG@Ru NFS) and its photocatalytic performance was reported. Synthesis of MgB2@Ru, MgB2/GG@Ru NFS and commercial MgB2, was studied by FTIR, XRD, FE-SEM, EDX, AFM, TEM, UV-vis spectra, and XPS analysis. From the results, the MgB2/GG@Ru NFS exhibited a superior photocatalytic performance (99.7 %) than its precursors MgB2@Ru (79.7 %), and MgB2 (53.7 %), with the degradation efficiency of the crystal violet (CV) within 100 min under visible light irradiation. The proposed photo-catalyst MgB2/GG@Ru NFS showed negligible loss of photocatalytic activity even after five successive cycles, revealing its reusability and enhanced stability due to the network structure. The photocatalytic mechanism for MgB2/GG@Ru NFS was evaluated by trapping experiment of active species, verifying that superoxide (O2-) and electron (e-) contributed significant role in the dye degradation.
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Affiliation(s)
- Ramasubba Reddy Palem
- Department of Medical Biotechnology, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi 10326, Republic of Korea
| | - Chinna Bathula
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Ganesh Shimoga
- Department of Biotechnology and Nanomedicine, SINTEF Industry, 7034 Trondheim, Norway; Interaction Lab, Future Convergence Engineering, Advanced Technology Research Centre, Korea University of Technology and Education, Cheonan-si 31253, Chungcheongnam-do, Republic of Korea
| | - Soo-Hong Lee
- Department of Medical Biotechnology, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi 10326, Republic of Korea
| | - Ayman A Ghfar
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Sankar Sekar
- Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea; Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Hyun-Seok Kim
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Young-Soo Seo
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Iqra Rabani
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea.
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Ahmed ATA, Ansari AS, Sree VG, Jana A, Meena A, Sekar S, Cho S, Kim H, Im H. Nitrogen-Doped CuO@CuS Core-Shell Structure for Highly Efficient Catalytic OER Application. Nanomaterials (Basel) 2023; 13:3160. [PMID: 38133057 PMCID: PMC10745488 DOI: 10.3390/nano13243160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Water electrolysis is a highly efficient route to produce ideally clean H2 fuel with excellent energy conversion efficiency and high gravimetric energy density, without producing carbon traces, unlike steam methane reforming, and it resolves the issues of environmental contamination via replacing the conventional fossil fuel. Particular importance lies in the advancement of highly effective non-precious catalysts for the oxygen evolution reaction (OER). The electrocatalytic activity of an active catalyst mainly depends on the material conductivity, accessible catalytically active sites, and intrinsic OER reaction kinetics, which can be tuned via introducing N heteroatoms in the catalyst structure. Herein, the efficacious nitrogenation of CuS was accomplished, synthesized using a hydrothermal procedure, and characterized for its electrocatalytic activity towards OER. The nitrogen-doped CuO@CuS (N,CuO@CuS) electrocatalyst exhibited superior OER activity compared to pristine CuS (268 and 602 mV), achieving a low overpotential of 240 and 392 mV at a current density of 10 and 100 mA/cm2, respectively, ascribed to the favorable electronic structural modification triggered by nitrogen incorporation. The N,CuO@CuS also exhibits excellent endurance under varied current rates and a static potential response over 25 h with stability measured at 10 and 100 mA/cm2.
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Affiliation(s)
- Abu Talha Aqueel Ahmed
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Abu Saad Ansari
- Center of Excellence Applied Nanotechnology, Nano Center Indonesia Research Institute, Banten 15314, Indonesia;
| | - Vijaya Gopalan Sree
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Atanu Jana
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Abhishek Meena
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Sankar Sekar
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Sangeun Cho
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Hyungsang Kim
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
| | - Hyunsik Im
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea; (A.T.A.A.); (V.G.S.); (A.J.); (A.M.); (S.S.); (S.C.); (H.K.)
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Sekar S, Yun JS, Lee S. Metal-free electrocatalytic nanocomposites of poly azovan blue-decorated graphitic carbon nitride for simultaneously sensing paracetamol and 4-aminophenol. Environ Res 2023; 239:117293. [PMID: 37816424 DOI: 10.1016/j.envres.2023.117293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/25/2023] [Accepted: 10/02/2023] [Indexed: 10/12/2023]
Abstract
Excessive consumption of paracetamol (PA) and 4-aminophenol (4-AP) can have harmful effects on the human body. This study developed a novel electroanalytical technique that utilizes the nanocomposites of poly azovan blue (PAB)-decorated graphitic carbon nitride (g-C3N4), deposited onto a screen-printed carbon electrode (SPCE), for the concurrent sensing of PA and 4-AP. The fabricated g-C3N4@PAB/SPCE exhibited exceptional synergistic effects, such as a high active electrochemical surface area and excellent electron transfer properties. The electrochemical behavior of g-C3N4@PAB/SPCE for simultaneous PA and 4-AP sensing was evaluated in the linear dynamic ranges of 0.08-75 and 0.05-90 μM, with the detection limits (S/N = 3) of 0.011 and 0.016 μM and sensitivities of 2.974 and 2.857 μA/μM/cm-2 for PA and 4-AP, respectively. Additionally, g-C3N4@PAB/SPCE showed long-term stability, high reproducibility (RSD = 2.17%, n = 4), and superior anti-interference capabilities. Finally, when g-C3N4@PAB/SPCE was tested for simultaneously sensing both PA and 4-AP in tap water and artificial urine models, it exhibited satisfactory recoveries, demonstrating its potential use for various industrial and clinical applications.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Ji-Seop Yun
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea.
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Jin Lee D, Mohan Kumar G, Sekar S, Chang Jeon H, Young Kim D, Ilanchezhiyan P. Ultrasonic processing of WO 3 nanosheets integrated Ti 3C 2 MXene 2D-2D based heterojunctions with synergistic effects for enhanced water splitting and environmental remediation. Ultrason Sonochem 2023; 101:106681. [PMID: 37952468 PMCID: PMC10665665 DOI: 10.1016/j.ultsonch.2023.106681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023]
Abstract
This article describes a straightforward chemical procedure that involves hydrothermal and ultrasonic treatments to create a new 2D/2D ultrathin WO3/Ti3C2 heterojunctions. The features of the fabricated heterojunctions were characterized and examined by field emission electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), optical absorption spectroscopy (UV-Vis). By photodegrading an organic dye under the influence of visible light, the photocatalytic degradation capabilities of the heterojunctions were also investigated. The performance of WO3/Ti3C2 was superior to that of bare WO3, with a removal rate of 94% and a kinetic rate constant (k) that was approximately 3 times that of WO3. The creation of 2D/2D heterojunction was observed to encourage the spatial charge separation and increase the surface reactive sites, to result with the increased photocatalytic activity in WO3/Ti3C2 heterojunction. The photocurrent values discovered through photoelectrochemical studies further indicated Ti3C2's active function in enhancing water-splitting performance. The impedance analysis examined by an electrochemical method revealed that heterojunctions might be helpful in accelerating the migration of charges quickly to get the outcomes seen.
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Affiliation(s)
- Dong Jin Lee
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea
| | - Ganesan Mohan Kumar
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea
| | - Sankar Sekar
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea
| | - Hee Chang Jeon
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea
| | - Deuk Young Kim
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea; Division of Physics and Semiconductor Science, Dongguk University, Seoul, Republic of Korea
| | - Pugazhendi Ilanchezhiyan
- Quantum-Functional Semiconductor Research Center (QSRC), Institute of Future Technology, Dongguk University, Jung-gu, Seoul 04620, South Korea.
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Priya S, Murali A, Mohan S, Lakshminarayanan A, Sekar S, Ramesh R, Devendiran M, Han SS. In vitro anti-prostate adenocarcinoma and lung cancer studies of phenoxyaniline- block-poly(methyl methacrylate) based nanocomposites via controlled radical polymerization. Nanoscale Adv 2023; 5:5870-5879. [PMID: 37881709 PMCID: PMC10597550 DOI: 10.1039/d3na00644a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/14/2023] [Indexed: 10/27/2023]
Abstract
A phenoxyaniline-based macroinitiator is utilized for the first time in order to produce phenoxyaniline-block-poly(methyl methacrylate) composites through single electron transfer-living radical polymerization (SET-LRP) under mild conditions. A different weight percentage of Cloisite 93A is added into the polymer mixtures in order to increase their biochemical properties. The prepared block copolymer nanocomposites are characterized using ATR-IR, UV-vis-spectroscopy, XRD, Raman, TGA, DSC, a particle size analyzer, contact angle measurements and SEM in order to characterize their structural, thermal, surface and morphological properties. Further, the developed polymeric nanocomposites are successfully applied in two different cancer cell lines (prostate adenocarcinoma and lung cancer), which show excellent anticancer properties. Also, acridine orange/ethidium bromide (AO/EtBr) dual staining is performed, which causes drastic cell death by apoptosis in both A549 and PC-3 cell lines, which indicated that the prepared polymeric nanocomposites effectively inhibit the cell proliferation and induce the apoptosis in both the cancer cells. Here nanoclay is used for cancer treatment because of its complete water solubility, which essentially causes the formation of a cationic complex between the clay and drug through electrostatic interactions. Hence, the exchange of ions between the clay and other ions in the biological environment leads to inhibition of the proliferation of prostate adenocarcinoma and lung cancer cells in the system.
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Affiliation(s)
- Sahariya Priya
- School of Chemical Engineering, Yeungnam University 280 Daehak-Ro Gyeongsan Gyeongbuk 38541 Republic of Korea
| | - Adhigan Murali
- School for Advanced Research in Petrochemicals (SARP)- ARSTPS, Central Institute of Petrochemicals Engineering & Technology (CIPET), Govt. of India Chennai 600032 India
| | - Sakar Mohan
- Centre for Nano and Material Sciences, Jain University Bangalore 562112 Karnataka India
| | - A Lakshminarayanan
- Department of Pharmacology, Indira Medical College and Hospitals Tiruvallur Tamilnadu 631 203 India
| | - S Sekar
- School for Advanced Research in Petrochemicals (SARP)- ARSTPS, Central Institute of Petrochemicals Engineering & Technology (CIPET), Govt. of India Chennai 600032 India
| | - R Ramesh
- Department of Chemical Engineering, School of Mechanical, Chemical and Material Engineering, Adama Science and Technology University, Adama P.O. Box: 1888 Adama Ethiopia
| | - M Devendiran
- Vels Institute of Science Technology and Advanced Studies (VISTAS) Pallavaram Chennai 117 India
| | - Sung Soo Han
- School of Chemical Engineering, Yeungnam University 280 Daehak-Ro Gyeongsan Gyeongbuk 38541 Republic of Korea
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Bathula C, Meena A, Sekar S, Singh AN, Soni R, El-Marghany A, Palem RR, Kim HS. Self-Assembly of Copper Oxide Interfaced MnO 2 for Oxygen Evolution Reaction. Nanomaterials (Basel) 2023; 13:2329. [PMID: 37630914 PMCID: PMC10459404 DOI: 10.3390/nano13162329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023]
Abstract
Designing efficient electrocatalytic systems through facile synthesis remains a formidable task. To address this issue, this paper presents the design of a combination material comprising two transition metal oxides (copper oxide and manganese oxide (CuO/MnO2)), synthesized using a conventional microwave technique to efficiently engage as an active oxygen evolution reaction (OER) catalyst. The structural and morphological properties of the composite were confirmed by the aid of X-ray diffraction (XRD) studies, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectrometry (EDS). FESEM clearly indicated well-aligned interlacing of CuO with MnO2. The OER performance was carried out in 1 M KOH. The assembled CuO/MnO2 delivered a benchmark current density (j = 10 mA cm-2) at a minimal overpotential (η = 294 mV), while pristine CuO required a high η (316 mV). Additionally, the CuO/MnO2 electrocatalyst exhibited stability for more than 15 h. These enhanced electrochemical performances were attributed to the large volume and expanded diameter of the pores, which offer ample surface area for catalytic reactions to boost OER. Furthermore, the rate kinetics of the OER are favored in composite due to low Tafel slope (77 mV/dec) compared to CuO (80 mV/dec).
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Affiliation(s)
- Chinna Bathula
- Division of Electronics and Electrical Engineering, Dongguk University–Seoul, Seoul 04620, Republic of Korea;
| | - Abhishek Meena
- Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea;
| | - Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea;
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Aditya Narayan Singh
- Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea;
| | - Ritesh Soni
- Department of Chemical Engineering, Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea;
| | - Adel El-Marghany
- Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia;
| | - Ramasubba Reddy Palem
- Department of Medical Biotechnology, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang 10326, Republic of Korea
| | - Hyun-Seok Kim
- Division of Electronics and Electrical Engineering, Dongguk University–Seoul, Seoul 04620, Republic of Korea;
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Sree VG, Naik S, Jana A, Kadam A, Sekar S, Im H, Kim HS, Sohn JI, Bathula C. Mechanochemically interlocked cubane copper complex interface for WOLED. J Colloid Interface Sci 2023; 633:589-597. [PMID: 36481422 DOI: 10.1016/j.jcis.2022.11.125] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/22/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022]
Abstract
In the rapid development of organic light-emitting diodes (OLEDs), phosphorescent transition metal complexes have played a crucial role as the most promising candidates for next generation display and lighting applications. However, most devices are fabricated using iridium and platinum-based complexes which are expensive and available in very limited quantities, whereas using relatively abundant organometallic complexes for fabrication results mostly in inefficient performance results. To overcome these issues, we have synthesized tetra copper iodide with tetra triphenyl cage like structure (denoted as CIPh) as an emerging class of luminescent material by mechanochemical grinding followed by thermal treatment for application in white OLED. The CIPh complex exhibits considerable quantum yield and a millisecond decay lifetime. Phosphorescent OLEDs were fabricated using CIPh complex as emitter shows a remarkable performance with external quantum efficiency and current efficiency of 5.28 % and 22.76 cd/A, with a high brightness of 4200 cd m-2, respectively. White OLEDs were also fabricated with a fluorescent blue and phosphorescent red emitted with (CIPh) as green emitter and achieved an impressive CRI of 82 with an EQE of over 3 %. This is the first ever attempt at fabricating WOLEDs using organocopper complex.
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Affiliation(s)
- Vijaya Gopalan Sree
- Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Soniya Naik
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Atanu Jana
- Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Abhijit Kadam
- Department of Chemistry, John Wilson Education Society's, Wilson College (Autonomous), Mumbai, Maharashtra 400007, India
| | - Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Hyunsik Im
- Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Hyun-Seok Kim
- Division of Electronics and Electrical Engineering, Dongguk University- Seoul, Seoul 04620, Republic of Korea
| | - Jung Inn Sohn
- Division of Physics and Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Chinna Bathula
- Division of Electronics and Electrical Engineering, Dongguk University- Seoul, Seoul 04620, Republic of Korea.
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Manikandan R, Sadhasivam S, Lee S, Cheol Chang S, Ashok Kumar K, Bathula C, Gopalan Sree V, Young Kim D, Sekar S. Deep Eutectic Solvents Assisted Synthesis of AC-decorated NiO Nanocomposites for Hydrogen Evolution Reaction. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Sekar S, Lee S. In Situ Facile Synthesis of Low-Cost Biogenic Eggshell-Derived Nanohydroxyapatite/Chitosan Biocomposites for Orthopedic Implant Applications. Nanomaterials (Basel) 2022; 12:4302. [PMID: 36500924 PMCID: PMC9739235 DOI: 10.3390/nano12234302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
In situ facile synthesis and the characterization of nanohydroxyapatite/chitosan (nHAP/CS) biocomposites were investigated for examining their potential applications in orthopedic implant technology. Firstly, the bare nHAP, europium-doped hydroxyapatite (Eu-nHAP), yttrium-doped hydroxyapatite (Y-nHAP), and Eu- and Y-codoped hydroxyapatite (Eu,Y-nHAP) nanoparticles were synthesized by the wet precipitation technique using biowaste-eggshell-derived calcium oxide powders. Then, through ultrasonication using the nanohydroxyapatite/chitosan mixtures (molar ratio = 1:2), the nHAP/CS, Eu-nHAP/CS, Y-nHAP/CS, and Eu,Y-nHAP/CS biocomposites were fabricated. Among them, Eu,Y-nHAP/CS showed higher cell viability (94.9%), higher solubility (pH = 7.6 after 21 days), and greater antibacterial activity than those of the other composites. In addition, Eu,Y-nHAP/CS exhibited improved mechanical properties compared with the other composites. For example, the nanoindentation test displayed the Eu,Y-nHAP/CS-coated 316L stainless steel implant to possess a higher Young's modulus value (9.24 GPa) and greater hardness value (300.71 MPa) than those of the others. The results indicate that the biomass-eggshell-derived Eu,Y-doped nHAP is of good use for orthopedic implant applications.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
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Sekar S, Aqueel Ahmed AT, Sim DH, Lee S. Extraordinarily high hydrogen-evolution-reaction activity of corrugated graphene nanosheets derived from biomass rice husks. International Journal of Hydrogen Energy 2022; 47:40317-40326. [DOI: 10.1016/j.ijhydene.2022.02.233] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Aqueel Ahmed AT, Sekar S, Lee S, Im H, Preethi V, Ansari AS. Nitrogen-doped cobalt sulfide as an efficient electrocatalyst for hydrogen evolution reaction in alkaline and acidic media. International Journal of Hydrogen Energy 2022; 47:40340-40348. [DOI: 10.1016/j.ijhydene.2022.04.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Sekar S, Bathula C, Rabani I, Lee JW, Lee SH, Seo YS, Lee S. Enhanced photocatalytic crystal-violet degradation performances of sonochemically-synthesized AC-CeO 2 nanocomposites. Ultrason Sonochem 2022; 90:106177. [PMID: 36174271 PMCID: PMC9520071 DOI: 10.1016/j.ultsonch.2022.106177] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 05/28/2023]
Abstract
Semiconductor-based photocatalysis is one of the favorable techniques for the wastewater treatment. Herein, we synthesized the activated carbon-decorated cerium dioxide (AC-CeO2) nanocomposites via the facile ultrasonication method by using the biomass-derived AC nanoflakes and the sonochemically-synthesized CeO2 nanoparticles. The AC-CeO2 nanocomposites exhibited the aggregated morphology with the AC nanoflakes-anchored CeO2 nanoparticles. Since the hybridization of conductive AC and semiconductive CeO2 would lead to the increased photocarrier transport and the reduced photocarrier recombination, during the photocatalytic reaction, the AC-CeO2 nanocomposites showed the enhanced crystal violet dye-degradation efficiency up to 97.9 % within 135 min. The results suggest that the AC-CeO2 nanocomposites hold promise as a prominent photocatalyst for future green environmental technology.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Chinna Bathula
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Iqra Rabani
- Interface Lab, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Jin Woo Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - So Hyun Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea
| | - Young-Soo Seo
- Interface Lab, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Republic of Korea.
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Liuzhu Z, Sekar S, Chen J, Lee S, Kim DY, Manikandan R. A polyrutin/AgNPs coated GCE for simultaneous anodic stripping voltammetric determination of Pb(II) and Cd(II)ions in environmental samples. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sekar S, Huijun J, Liuzhu Z, Jin C, Lee S, Kim DY, Manikandan R. Copper phthalocyanine conjugated graphitic carbon nitride nanosheets as an efficient electrocatalyst for simultaneous detection of natural antioxidants. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140150] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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15
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Sekar S, Rabani I, Bathula C, Kumar S, Govindaraju S, Yun K, Seo YS, Kim DY, Lee S. Graphitic carbon-encapsulated V 2O 5 nanocomposites as a superb photocatalyst for crystal violet degradation. Environ Res 2022; 205:112201. [PMID: 34655605 DOI: 10.1016/j.envres.2021.112201] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/30/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
To materialize the excellent photocatalyst for crystal violet dye-degradation, the graphitic carbon-encapsulated vanadium pentoxide (GC-V2O5) nanocomposites were synthesized through the simple sonication method by using the green tea waste-derived GC nanoflakes and the sonochemically synthesized V2O5 nanorods. The nanocomposites were confirmed to comprise an aggregated morphology, in which the orthorhombic V2O5 nanorods were well anchored with the intertwingled GC nanoflakes. Owing to the encapsulation of defective V2O5 by conductive GC, the GC-V2O5 nanocomposites exhibited the enhanced photocatalytic dye-degradation efficiency up to 98.4% within 105 min. Namely, the encapsulated GC nanosheets might compensate the native defects (i.e., charge traps) on the V2O5 surface; hence, the charge transport could be enhanced during the dye-degradation process while the photocarrier recombination could be suppressed. The results suggest the conducting layer-encapsulated semiconducting oxide nanocomposites (e.g., GC-V2O5) to be of good use for future green environmental technology, particularly, as a superb photocatalyst for dye degradation.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Iqra Rabani
- Interface Lab, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul, 05006, Republic of Korea
| | - Chinna Bathula
- Division of Electronics and Electrical Engineering, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Subalakshmi Kumar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Saravanan Govindaraju
- Department of Bionanotechnology, Gachon University, Gyeonggi-do, 13120, Republic of Korea
| | - Kyusik Yun
- Department of Bionanotechnology, Gachon University, Gyeonggi-do, 13120, Republic of Korea
| | - Young-Soo Seo
- Interface Lab, Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul, 05006, Republic of Korea
| | - Deuk Young Kim
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea.
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16
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Sekar S, Preethi V, Saravanan S, Kim DY, Lee S. Excellent photocatalytic performances of Co 3O 4-AC nanocomposites for H 2 production via wastewater splitting. Chemosphere 2022; 286:131823. [PMID: 34426138 DOI: 10.1016/j.chemosphere.2021.131823] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 07/26/2021] [Accepted: 08/04/2021] [Indexed: 06/13/2023]
Abstract
Natural sunlight-driven photocatalytic hydrogen production from wastewater is one of the most desirable techniques that can realize future green energy technology. Herein, we report the synthesis and the characterization of the biomass activated carbon (AC)-decorated cobalt oxide (Co3O4) nanocomposites for solar-stimulated photocatalytic hydrogen production from sulphide wastewater. The Co3O4-AC nanocomposites were ultrasonically synthesized by using hydrothermally-grown spinel Co3O4 nanoflakes and biomass-derived AC nanoflakes. Co3O4-AC showed a nanobundle-like aggregated morphology, and exhibited a large specific surface area (~133 m2/g). Through utilizing Co3O4-AC as a photocatalyst for photocatalytic splitting of sulphide wastewater (0.2 M) under solar irradiance with 730 W/m2, an enhanced H2 production efficiency (~70 mL/h) was achieved owing to the synergic effects from 2-dimentionally configured Co3O4 and AC microstructures; i.e., large surface area of Co3O4 and high electrical conductivity of AC. These findings suggest the nanocomposites of Co3O4-AC to hold great promise for the green approach of photocatalytic wastewater splitting.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - V Preethi
- Renewable Energy Lab., Hindustan Institute of Technology and Science, Chennai, 603103, Tamil Nadu, India.
| | - S Saravanan
- Department of Mechanical Engineering, K. Ramakrishnan College of Technology, Trichy, 621112, Tamil Nadu, India
| | - Deuk Young Kim
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul, 04620, Republic of Korea.
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Arumugasamy SK, Chellasamy G, Sekar S, Lee S, Govindaraju S, Yun K. TriMOF synergized on the surface of activated carbon produced from pineapple leaves for the environmental pollutant reduction and oxygen evolution process. Chemosphere 2022; 286:131893. [PMID: 34403903 DOI: 10.1016/j.chemosphere.2021.131893] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Facile and modest synthesis of significantly effective and less-cost catalysts for environmental pollutant degradation and oxygen evolution holds substantial potential in environmental and energy fields. Hereby, Trimetallic organic frameworks (TriMOF) consisting of Fe, Co, and Zn synergized on the surface of activated carbon (AC) from pineapple leaves tend to show exponential catalytic activity due to the more excellent ionic conductivity, catalytic stability and multiple active sites provided by different metal precursors. Furthermore, the developed nanocomposite was coated on the stainless-steel electrode substrate at room temperature, delivering greater electrocatalytic surface area and numerous active sites. The oxidation reaction kinetics drives the catalytic reduction of 4-nitrophenol to 4-aminophenol with a minimal time of 12 min @ >97 % efficiency. Furthermore, on electrocatalytic oxidation of water splitting process due to the presence of multiple metallic, active sites, the overpotential is at 370 mV having Tafel slope of 40 mV/dec and electrochemically active surface area of is 9.9 mF/cm2. This superior catalytic reduction of 4-nitrophenol and electrocatalytic water oxidation process is attributed to the developed composite's active centre and conductivity.
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Affiliation(s)
- Shiva Kumar Arumugasamy
- Department of Bionanotechnology, Gachon University, Seongnam-daero, Gyeonggi-do, 13120, Republic of Korea
| | - Gayathri Chellasamy
- Department of Bionanotechnology, Gachon University, Seongnam-daero, Gyeonggi-do, 13120, Republic of Korea
| | - Sankar Sekar
- Department of Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Centre, Dongguk University, Seoul, 04620, Republic of Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea; Quantum-functional Semiconductor Research Centre, Dongguk University, Seoul, 04620, Republic of Korea
| | - Saravanan Govindaraju
- Department of Bionanotechnology, Gachon University, Seongnam-daero, Gyeonggi-do, 13120, Republic of Korea.
| | - Kyusik Yun
- Department of Bionanotechnology, Gachon University, Seongnam-daero, Gyeonggi-do, 13120, Republic of Korea.
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18
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Dhanasekar M, Sekar S, Bhat SV. Insights into the exceptional stability of the molecular precursor solution for Cu 2ZnSnS 4 solar absorber. J Colloid Interface Sci 2021; 599:326-331. [PMID: 33957425 DOI: 10.1016/j.jcis.2021.04.090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/12/2021] [Accepted: 04/18/2021] [Indexed: 11/27/2022]
Abstract
Environment friendly molecular precursors are extensively studied for green, economical and scalable fabrication of inorganic thin films for various device applications. For compound semiconductors such as the chalcogenide solar absorber Cu2ZnSnS4 (CZTS), the stability of such precursor solution is highly sought after. The longer shelf life of the precursor could significantly improve the phase purity as well as the reproducibility of the resulting films, and also would aid the industrial scaling up of the fabrication process. Herein, the reason behind the exceptional stability shown by a precursor solution for CZTS is explored, by probing the nature of interaction between its various components. The unique combination of solvent and the sulfur source is shown as favorable for the stable bonds in the solution, especially the predominant bidentate bridging of sulfur source to the metal atoms. The insights elucidated through simple spectroscopic techniques can be handy when designing such sustainable precursors for other functional chalcogenides and technologically important inorganic compounds.
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Affiliation(s)
- M Dhanasekar
- SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India; Department of Physics & Nanotechnology, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - S Sekar
- SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India; Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - S Venkataprasad Bhat
- SRM Research Institute, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India; Department of Physics & Nanotechnology, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India.
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19
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Sekar S, Lee S. Derivation of Luminescent Mesoporous Silicon Nanocrystals from Biomass Rice Husks by Facile Magnesiothermic Reduction. Nanomaterials (Basel) 2021; 11:613. [PMID: 33804437 PMCID: PMC7999164 DOI: 10.3390/nano11030613] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 01/04/2023]
Abstract
High-quality silicon (Si) nanocrystals that simultaneously had superior mesoporous and luminescent characteristics were derived from sticky, red, and brown rice husks via the facile and cost-effective magnesiothermic reduction method. The Si nanocrystals were confirmed to comprise an aggregated morphology with spherical nanocrystals (e.g., average sizes of 15-50 nm). Due to the surface functional groups formed at the nanocrystalline Si surfaces, the Si nanocrystals clearly exhibited multiple luminescence peaks in visible-wavelength regions (i.e., blue, green, and yellow light). Among the synthesized Si nanocrystals, additionally, the brown rice husk (BRH)-derived Si nanocrystals showed to have a strong UV absorption and a high porosity (i.e., large specific surface area: 265.6 m2/g, small average pore diameter: 1.91 nm, and large total pore volume: 0.5389 cm3/g). These are indicative of the excellent optical and textural characteristics of the BRH-derived Si nanocrystals, compared to previously reported biomass-derived Si nanocrystals. The results suggest that the biomass BRH-derived Si nanocrystals hold great potential as an active source material for optoelectronic devices as well as a highly efficient catalyst or photocatalyst for energy conversion devices.
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Affiliation(s)
- Sankar Sekar
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea;
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Sejoon Lee
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea;
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
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Sekar S, Aqueel Ahmed AT, Kim DY, Lee S. One-Pot Synthesized Biomass C-Si Nanocomposites as an Anodic Material for High-Performance Sodium-Ion Battery. Nanomaterials (Basel) 2020; 10:E1728. [PMID: 32878244 PMCID: PMC7558135 DOI: 10.3390/nano10091728] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023]
Abstract
Aiming at materializing an excellent anodic source material of the high-performance sodium-ion battery (SIB), we fabricated the biomass carbon-silicon (C-Si) nanocomposites by the one-pot synthesis of facile magnesiothermic reduction using brown rice husk ashes. The C-Si nanocomposites displayed an aggregated morphology, where the spherical Si nanoparticles (9 nm on average) and the C nanoflakes were encapsulated and decorated with each other. When utilizing the nanocomposites as an SIB anode, a high initial discharge capacity (i.e., 378 mAh/g at 100 mA/g) and a high reversible capacity (i.e., 122 mAh/g at 200 mA/g) were achieved owing to their enhanced electronic and ionic conductivities. Moreover, the SIB device exhibited a high cyclic stability in its Coulombic efficiency (i.e., 98% after 100 charge-discharge cycles at 200 mA/g). These outstanding results depict that the one-pot synthesized biomass C-Si nanocomposites are beneficial for future green energy-storage technology.
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Affiliation(s)
- Sankar Sekar
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (A.T.A.A.); (D.Y.K.)
- Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Abu Talha Aqueel Ahmed
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (A.T.A.A.); (D.Y.K.)
| | - Deuk Young Kim
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (A.T.A.A.); (D.Y.K.)
- Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Sejoon Lee
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (A.T.A.A.); (D.Y.K.)
- Quantum-functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
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21
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Sekar S, Kim DY, Lee S. Excellent Oxygen Evolution Reaction of Activated Carbon-Anchored NiO Nanotablets Prepared by Green Routes. Nanomaterials (Basel) 2020; 10:E1382. [PMID: 32679812 PMCID: PMC7408599 DOI: 10.3390/nano10071382] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 01/13/2023]
Abstract
A sustainable and efficient electrocatalyst for the oxygen evolution reaction (OER) is vital to realize green and clean hydrogen production technology. Herein, we synthesized the nanocomposites of activated carbon-anchored nickel oxide (AC-NiO) via fully green routes, and characterized their excellent OER performances. The AC-NiO nanocomposites were prepared by the facile sonication method using sonochemically prepared NiO nanoparticles and biomass-derived AC nanosponges. The nanocomposites exhibited an aggregated structure of the AC-NiO nanotablets with an average size of 40 nm. When using the nanotablets as an OER catalyst in 1 M KOH, the sample displayed superb electrocatalytic performances, i.e., a substantially low value of overpotential (320 mV at 10 mA/cm2), a significantly small Tafel slope (49 mV/dec), and a good OER stability (4% decrease of overpotential after 10 h). These outstanding OER characteristics are considered as attributing to the synergetic effects from both the ample surface area of the electrochemically active NiO nanoparticles and the high electrical conductivity of the AC nanosponges. The results pronounce that the fully ecofriendly synthesized AC-NiO nanotablets can play a splendid role as high-performance electrocatalysts for future green energy technology.
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Affiliation(s)
- Sankar Sekar
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (D.Y.K.)
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Deuk Young Kim
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (D.Y.K.)
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Sejoon Lee
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea; (S.S.); (D.Y.K.)
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
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RajKumar G, Udhaya Sankar G, Ravi G, Moorthy CG, Sekar S. Portable Network Graphics Approach to the Authentication of Halftone Images with Henon Map Encryption. Smart Science 2020. [DOI: 10.1080/23080477.2020.1769978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- G. RajKumar
- Department of Electrical Electronic Engineering, Nehru College of Engineering and Research Centre, Pampady, India
- Department of EEE, Hindustan Institute of Technology and Science, Chennai, India
| | | | - G. Ravi
- Department of Physics, Alagappa University, Karaikudi, India
| | | | - S. Sekar
- Department of EEE, Hindustan Institute of Technology and Science, Chennai, India
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Sekar S, Aqueel Ahmed AT, Inamdar AI, Lee Y, Im H, Kim DY, Lee S. Activated Carbon-Decorated Spherical Silicon Nanocrystal Composites Synchronously-Derived from Rice Husks for Anodic Source of Lithium-Ion Battery. Nanomaterials (Basel) 2019; 9:E1055. [PMID: 31340552 PMCID: PMC6669463 DOI: 10.3390/nano9071055] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 01/07/2023]
Abstract
The nanocomposites of activated-carbon-decorated silicon nanocrystals (ACAC) were synchronously derived in a single step from biomass rice husks, through the simple route of the calcination method together with the magnesiothermic reduction process. The final product, ACAC, exhibited an aggregated structure of activated-carbon-encapsulated nanocrystalline silicon spheres, and reveals a high specific surface area (498.5 m2/g). Owing to the mutualization of advantages from both silicon nanocrystals (i.e., low discharge potential and high specific capacity) and activated carbon (i.e., high porosity and good electrical conductivity), the ACAC nanocomposites are able to play a substantial role as an anodic source material for the lithium-ion battery (LIB). Namely, a high coulombic efficiency (97.5%), a high discharge capacity (716 mAh/g), and a high reversible specific capacity (429 mAh/g after 100 cycles) were accomplished when using ACAC as an LIB anode. The results advocate that the simultaneous synthesis of biomass-derived ACAC is beneficial for green energy-storage device applications.
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Affiliation(s)
- Sankar Sekar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | | | - Akbar I Inamdar
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea
| | - Youngmin Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Hyunsik Im
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Deuk Young Kim
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea
| | - Sejoon Lee
- Department of Semiconductor Science, Dongguk University-Seoul, Seoul 04620, Korea.
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04620, Korea.
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Abstract
2D-BCNO transfers some energy to excite Eu3+ ions and together they generate white light.
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Affiliation(s)
- S. Sekar
- SRM Research Institute
- SRM Institute of Science and Technology
- Kancheepuram
- India
- Department of Chemistry
| | - S. Venkataprasad Bhat
- SRM Research Institute
- SRM Institute of Science and Technology
- Kancheepuram
- India
- Department of Physics & Nanotechnology
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Padmapriyadarsini C, Ramesh K, Sekar L, Ramachandran G, Reddy D, Narendran G, Sekar S, Chandrasekar C, Anbarasu D, Wanke C, Swaminathan S. Factors affecting high-density lipoprotein cholesterol in HIV-infected patients on nevirapine-based antiretroviral therapy. Indian J Med Res 2018; 145:641-650. [PMID: 28948955 PMCID: PMC5644299 DOI: 10.4103/ijmr.ijmr_1611_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background & objectives: Cardiovascular disease (CVD) risk with low high-density lipoprotein cholesterol (HDL-C) and high triglycerides is common in the general population in India. As nevirapine (NVP)-based antiretroviral therapy (ART) tends to increase HDL-C, gene polymorphisms associated with HDL-C metabolism in HIV-infected adults on stable NVP-based ART were studied. Methods: A cross-sectional study was conducted between January 2013 and July 2014 among adults receiving NVP-based ART for 12-15 months. Blood lipids were estimated and gene polymorphisms in apolipoprotein C3 (APOC3), cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genes were analyzed by real-time polymerase chain reaction. Framingham's 10-yr CVD risk score was estimated. Logistic regression was done to show factors related to low HDL-C levels. Results: Of the 300 patients included (mean age: 38.6±8.7 yr; mean CD4 count 449±210 cell/μl), total cholesterol (TC) >200 mg/dl was observed in 116 (39%) patients. Thirty nine per cent males and 47 per cent females had HDL-C levels below normal while 32 per cent males and 37 per cent females had TC/HDL ratio of 4.5 and 4.0, respectively. Body mass index [adjusted odds ratio (aOR)=1.70, 95% confidence interval (CI) 1.01-2.84, P=0.04] and viral load (aOR=3.39, 95% CI: 1.52-7.52, P=0.003) were negatively associated with serum HDL-C levels. The 10-yr risk score of developing CVD was 11-20 per cent in 3 per cent patients. Allelic variants of APOC3 showed a trend towards low HDL-C. Interpretation & conclusions: High-risk lipid profiles for atherosclerosis and cardiovascular disease were common among HIV-infected individuals, even after 12 months of NVP-based ART. Targeted interventions to address these factors should be recommended in the national ART programmes.
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Affiliation(s)
- C Padmapriyadarsini
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - K Ramesh
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - L Sekar
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - Geetha Ramachandran
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - Devaraj Reddy
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - G Narendran
- Department of Clinical Research, ICMR-National Institute for Research in Tuberculosis, Chennai, India
| | - S Sekar
- ART Centre, Rajiv Gandhi Government General Hospital, Chennai, India
| | - C Chandrasekar
- Nodal ART Medical Officer, Government Hospital of Thoracic Medicine, Chennai, India
| | - D Anbarasu
- ART Centre, Government Vellore Medical College & Hospital, Vellore, India
| | - Christine Wanke
- Department of Medicine, Tufts University School of Medicine, Boston, USA
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Schmidt J, Stein C, Poorman K, Lehman J, Mangold A, Costello C, Nelson S, DiCaudo D, Sharma A, Cappel M, Sekar S, Tassone E, Adkins J, Drenner K, Liang W, Sekulic A. 1000 Molecular mapping of necrobiosis lipoidica for identification of disease mechanisms and novel therapeutic strategies. J Invest Dermatol 2018. [DOI: 10.1016/j.jid.2018.03.1012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sekar S, Muller JG, Karthikeyan J, Murugan P, Lakshminarasimhan N. Unveiling the multifunctional roles of hitherto known capping ligand oleic acid as blue emitter and sensitizer in tuning the emission colour to white in red-emitting phosphors. Phys Chem Chem Phys 2018; 20:19087-19097. [DOI: 10.1039/c8cp02954g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multifunctional roles of oleic acid as capping ligand, blue emitter and sensitizer are revealed in obtaining white light emission from Eu3+-based red phosphors.
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Affiliation(s)
- S. Sekar
- Functional Materials Division
- CSIR-Central Electrochemical Research Institute
- Karaikudi 630 003
- India
| | - J. George Muller
- Functional Materials Division
- CSIR-Central Electrochemical Research Institute
- Karaikudi 630 003
- India
| | - J. Karthikeyan
- Functional Materials Division
- CSIR-Central Electrochemical Research Institute
- Karaikudi 630 003
- India
- Academy of Scientific and Innovative Research
| | - P. Murugan
- Functional Materials Division
- CSIR-Central Electrochemical Research Institute
- Karaikudi 630 003
- India
- Academy of Scientific and Innovative Research
| | - N. Lakshminarasimhan
- Functional Materials Division
- CSIR-Central Electrochemical Research Institute
- Karaikudi 630 003
- India
- Academy of Scientific and Innovative Research
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Alex MJ, Periasamy P, Mohan K, Sekar S, Prabha KKS, Venkatachalam R. In situ synthesised TiO2-chitosan-chondroitin 4-sulphate nanocomposites for bone implant applications. IET Nanobiotechnol 2016; 10:107-13. [PMID: 27256888 DOI: 10.1049/iet-nbt.2015.0023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The artificial materials for bone implant applications are gaining more importance in the recent years. The series titania-chitosan-chondroitin 4-sulphate nanocomposites of three different concentrations (2:1:x, where x- 0.125, 0.25, 0.5) have been synthesised by in situ sol-gel method and characterised by various techniques. The particle size of the nanocomposites ranges from 30-50 nm. The bioactivity, swelling nature, and the antimicrobial nature of the nanocomposites were investigated. The swelling ability and bioactivity of the composites is significantly greater and they possess high zone of inhibition against the microorganisms such as Staphylococcus aureus and Escherichia coli. The cell viability of the nanocomposites were evaluated by using MG-63 and observed the composites possess high cell viability at low concentration. The excellent bioactivity and biocompatibility makes these nanocomposites a promising biomaterial for bone implant applications.
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Affiliation(s)
- Martina Jenitha Alex
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India
| | - Prabu Periasamy
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India.
| | - Kalirajan Mohan
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India
| | - Sankar Sekar
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India
| | - Kavitha Kandiah Suriya Prabha
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India
| | - Rajendran Venkatachalam
- Centre for Nano Science and Technology, K S Rangasamy College of Technology, Tiruchengode-637 215, Tamil Nadu, India
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Sekar S, Lemaire V, Hu H, Decher G, Pauly M. Anisotropic optical and conductive properties of oriented 1D-nanoparticle thin films made by spray-assisted self-assembly. Faraday Discuss 2016; 191:373-389. [DOI: 10.1039/c6fd00017g] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on the fabrication of oriented anisotropic metal nanoparticle thin films made by Grazing Incidence Spraying (GIS) and on the anisotropic plasmonic properties of the resulting thin films. Gold nanorods of two different aspect ratios and silver nanowires were self-assembled as a uniaxially aligned monolayer with the GIS approach. In particular, we examine the influence of the nanowire/nanorod length and diameter on the degree of ordering determined by electron microscopy pictures. Furthermore, we show that the anisotropy of the optical properties (probed by polarized UV-visible-near infrared spectroscopy) strongly depend on the quality of alignment. The prepared monolayer thin films have an orientation order parameter of up to 0.83 for silver nanowires, which is reflected in an optical anisotropy of 0.57 in the UV-visible and 0.76 in the near infrared through the selective excitation of transverse and longitudinal surface plasmon resonance modes. The electronic transport in oriented silver nanowire monolayers is also shown to be highly directional, with the sheet resistance varying over almost an order of magnitude depending on the transport direction. Such anisotropic conductive plasmonic thin films may find applications in various fields like biochemical sensing, energy transport and harvesting or optoelectronic devices.
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Affiliation(s)
- S. Sekar
- Institut Charles Sadron
- CNRS (UPR22)
- F-67034 Strasbourg
- France
- Faculté de Chimie
| | - V. Lemaire
- Institut Charles Sadron
- CNRS (UPR22)
- F-67034 Strasbourg
- France
- Faculté de Chimie
| | - H. Hu
- Institut Charles Sadron
- CNRS (UPR22)
- F-67034 Strasbourg
- France
- Faculté de Chimie
| | - G. Decher
- Institut Charles Sadron
- CNRS (UPR22)
- F-67034 Strasbourg
- France
- Faculté de Chimie
| | - M. Pauly
- Institut Charles Sadron
- CNRS (UPR22)
- F-67034 Strasbourg
- France
- Faculté de Chimie
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Vitorazi L, Ould-Moussa N, Sekar S, Fresnais J, Loh W, Chapel JP, Berret JF. Evidence of a two-step process and pathway dependency in the thermodynamics of poly(diallyldimethylammonium chloride)/poly(sodium acrylate) complexation. Soft Matter 2014; 10:9496-9505. [PMID: 25347132 DOI: 10.1039/c4sm01461h] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recent studies have pointed out the importance of polyelectrolyte assembly in the elaboration of innovative nanomaterials. Beyond their structures, many important questions on the thermodynamics of association remain unanswered. Here, we investigate the complexation between poly(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium acrylate) (PANa) chains using a combination of three techniques: isothermal titration calorimetry (ITC), static and dynamic light scattering and electrophoresis. Upon addition of PDADMAC to PANa or vice-versa, the results obtained by the different techniques agree well with each other, and reveal a two-step process. The primary process is the formation of highly charged polyelectrolyte complexes of size 100 nm. The secondary process is the transition towards a coacervate phase made of rich and poor polymer droplets. The binding isotherms measured are accounted for using a phenomenological model that provides the thermodynamic parameters for each reaction. Small positive enthalpies and large positive entropies consistent with a counterion release scenario are found throughout this study. Furthermore, this work stresses the importance of the underestimated formulation pathway or mixing order in polyelectrolyte complexation.
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Affiliation(s)
- L Vitorazi
- Matière et Systèmes Complexes, UMR 7057 CNRS Université Denis Diderot Paris-VII, Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris, France.
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Mandal A, Sekar S, Chandrasekaran N, Mukherjee A, Sastry TP. Poly(ethylene) glycol-capped silver and magnetic nanoparticles: synthesis, characterization, and comparison of bactericidal and cytotoxic effects. Proc Inst Mech Eng H 2013; 227:1224-36. [PMID: 23959858 DOI: 10.1177/0954411913499290] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Silver and magnetic (Fe3O4) nanoparticles have attracted wide attention as novel antimicrobial agents due to their unique chemical and physical properties. In order to study the comparative effects on antibacterial and animal cytotoxicity, Staphylococcus aureus and NIH 3T3 fibroblasts were used, respectively. Both nanoparticles were synthesized via a novel matrix-mediated method using poly(ethylene) glycol. Formation of silver nanoparticles was confirmed by fluorescence and ultraviolet-visible spectroscopic techniques. The poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles were characterized by scanning electron microscope, transmission electron microscope, zeta potential, particle size analysis, Fourier-transform infrared, X-ray diffraction, and X-ray photoelectron spectroscopy. The antimicrobial results indicate that both poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles inhibited S. aureus growth at the concentrations of 5 and 10 µg/mL at all time points without showing any significant cytotoxicity on NIH 3T3 fibroblasts. The particle size of both the poly(ethylene) glycol-coated silver and Fe3O4 nanoparticles dominated in the range 10-15 nm, obtained by particle size analyzer. The poly(ethylene) glycol coating on the particles showed less aggregation of nanoparticles, as observed by scanning electron microscope and transmission electron microscope. The overall obtained results indicated that these two nanoparticles were stable and could be used to develop a magnetized antimicrobial scaffolds for biomedical applications.
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Affiliation(s)
- A Mandal
- Centre for Nano-Biotechnology, School of Bio-Sciences and Technology, VIT University, Vellore, Tamil Nadu, India
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Abstract
The aim of this study was to evaluate the efficacy of Al2(SO4)3 cross-linked human amniotic membrane for ocular surface reconstruction using tissue culture techniques. The human amniotic membrane was cross-linked with Al2(SO4)3, and the cross-linked human amniotic membrane was characterized for its mechanical properties, percentage of swelling in water, sterility, infrared spectroscopy and scanning electron microscopy. The potential of cross-linked human amniotic membrane to support the attachment and proliferation of corneal limbal epithelial cells was assessed in vitro, using static culture system. About 125% increase in the tensile strength was observed in the cross-linked human amniotic membrane compared to human amniotic membrane. Infrared spectroscopy studies have confirmed the cross-linking of human amniotic membrane with Al2(SO4)3. The cross-linked human amniotic membrane was found to be sterile up to 1 year. In culture studies, confluent sheets of epithelial cells were seen at the end of 14th day resembling the morphological features of limbal epithelia. The cross-linked human amniotic membrane has exhibited improved mechanical properties, and the tissue culture studies have shown its feasibility to be used as a limbal transplant. It was concluded that the crosslinked human amniotic membrane with its improved mechanical properties could be used on par with human amniotic membrane.
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Affiliation(s)
- S Sekar
- Bio-Products Laboratory, Central Leather Research Institute, Chennai, India
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33
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Sekar S, Jonckers E, Verhoye M, Willems R, Veraart J, Van Audekerke J, Couto J, Giugliano M, Wuyts K, Dedeurwaerdere S, Sijbers J, Mackie C, Ver Donck L, Steckler T, Van der Linden A. Subchronic memantine induced concurrent functional disconnectivity and altered ultra-structural tissue integrity in the rodent brain: revealed by multimodal MRI. Psychopharmacology (Berl) 2013; 227:479-91. [PMID: 23354531 DOI: 10.1007/s00213-013-2966-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 01/03/2013] [Indexed: 10/27/2022]
Abstract
BACKGROUND An effective NMDA antagonist imaging model may find key utility in advancing schizophrenia drug discovery research. We investigated effects of subchronic treatment with the NMDA antagonist memantine by using behavioural observation and multimodal MRI. METHODS Pharmacological MRI (phMRI) was used to map the neuroanatomical binding sites of memantine after acute and subchronic treatment. Resting state fMRI (rs-fMRI) and diffusion MRI were used to study the changes in functional connectivity (FC) and ultra-structural tissue integrity before and after subchronic memantine treatment. Further corroborating behavioural evidences were documented. RESULTS Dose-dependent phMRI activation was observed in the prelimbic cortex following acute doses of memantine. Subchronic treatment revealed significant effects in the hippocampus, cingulate, prelimbic and retrosplenial cortices. Decreases in FC amongst the hippocampal and frontal cortical structures (prelimbic, cingulate) were apparent through rs-fMRI investigation, indicating a loss of connectivity. Diffusion kurtosis MRI showed decreases in fractional anisotropy and mean diffusivity changes, suggesting ultra-structural changes in the hippocampus and cingulate cortex. Limited behavioural assessment suggested that memantine induced behavioural effects comparable to other NMDA antagonists as measured by locomotor hyperactivity and that the effects could be reversed by antipsychotic drugs. CONCLUSION Our findings substantiate the hypothesis that repeated NMDA receptor blockade with nonspecific, noncompetitive NMDA antagonists may lead to functional and ultra-structural alterations, particularly in the hippocampus and cingulate cortex. These changes may underlie the behavioural effects. Furthermore, the present findings underscore the utility and the translational potential of multimodal MR imaging and acute/subchronic memantine model in the search for novel disease-modifying treatments for schizophrenia.
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Affiliation(s)
- S Sekar
- Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Campus Drie Eiken, D.UC.109, Universiteitsplein 1, 2610, Wilrijk, Belgium.
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Sundar JS, Uma T, Parameswari S, Sekar S, Kabilan N, Natarajan M. A rare combination of disease presentation of HIV positive person, attending Government Hospital, Chennai – a case report. BMC Infect Dis 2012. [PMCID: PMC3344731 DOI: 10.1186/1471-2334-12-s1-p37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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35
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Uma T, Srijayanth P, Valarmathi S, Sekar S, Kabilan N, Natarajan M. Socio-demographic profile of HIV/AIDS patients at ART centres in Chennai. BMC Infect Dis 2012. [PMCID: PMC3344751 DOI: 10.1186/1471-2334-12-s1-p53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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36
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Ramnath V, Sekar S, Sankar S, Sankaranarayanan C, Sastry TP. Preparation and evaluation of biocomposites as wound dressing material. J Mater Sci Mater Med 2012; 23:3083-95. [PMID: 23015263 DOI: 10.1007/s10856-012-4765-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 09/08/2012] [Indexed: 06/01/2023]
Abstract
Collagen was isolated from the chrome containing leather waste (CCLW) which is a major solid waste in leather industry. Composite films were made using sago starch (SG), soya protein (SY), and collagen (C) and were cross linked with glutaraldehyde (G).The films prepared were characterized for their physico chemical properties like tensile strength, infrared spectra, thermogravimetric analysis, surface morphology, and water absorption studies. Better mechanical properties and surface morphology were observed for SG-SY-G-C films compared to other films prepared using collagen. The composite films prepared were used as wound dressing material on the experimental wounds of rats and healing pattern was evaluated using planimetric, biochemical, and histopathological studies. These studies have revealed better wound healing capacity of SG-SY-G-C film and utilization of CCLW in the preparation of value added product like wound dressing material.
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Affiliation(s)
- V Ramnath
- Bioproducts Lab, Central Leather Research Institute, Adyar, Chennai, 600020, India
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37
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Marie Arockianathan P, Sekar S, Sankar S, Kumaran B, Sastry TP. Evaluation of biocomposite films containing alginate and sago starch impregnated with silver nano particles. Carbohydr Polym 2012; 90:717-24. [PMID: 24751098 DOI: 10.1016/j.carbpol.2012.06.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 05/09/2012] [Accepted: 06/02/2012] [Indexed: 10/28/2022]
Abstract
In recent years, the metal nanoparticles/polymer composites have created lot of attraction due to their wide range of applications. In the present study, the composite films of alginate (AL) and sago starch (SG) impregnated with silver nano particles (AgNP) with and without antibiotic gentamicin (G) were prepared by solvent casting method. The films prepared were characterized for thermo gravimetric analysis, SEM, TEM and mechanical properties and the results have shown the composite nature of the films. AL-SG-AgNP and AL-SG-AgNP-G composites were used as wound dressing materials in experimental wounds of rats. The healing pattern of the wounds was evaluated by planimetric studies, macroscopic observations, biochemical studies and histopathological observations. The results have shown faster healing pattern in the wounds treated with AL-SG-AgNP and AL-SG-AgNP-G composites compared to untreated control. This study revealed that AL-SG-AgNP film might be a potential and economical wound dressing material.
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Affiliation(s)
- P Marie Arockianathan
- Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India
| | - S Sekar
- Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India
| | - S Sankar
- Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India
| | - B Kumaran
- K.M Centre for P.G Studies, Lawspet, Puducherry 605008, India
| | - T P Sastry
- Bio-products Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India
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38
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Arockianathan PM, Sekar S, Kumaran B, Sastry TP. Preparation, characterization and evaluation of biocomposite films containing chitosan and sago starch impregnated with silver nanoparticles. Int J Biol Macromol 2012; 50:939-46. [PMID: 22390849 DOI: 10.1016/j.ijbiomac.2012.02.022] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 02/09/2012] [Accepted: 02/18/2012] [Indexed: 11/20/2022]
Abstract
The positive attributes of excellent biocompatibility and biodegradability of biopolymers with versatile biological activities have provided ample opportunities for further development of functional biomaterials of high potential in various fields. The biopolymers used in this study, i.e. chitosan and sago starch are abundantly available in nature and can be used in various biomedical applications. In the present study, the composite films of chitosan (Ch) and sago starch (SG) impregnated with silver nanoparticles (AgNP) with and without antibiotic gentamicin (G) were prepared by solvent casting method. The films prepared were characterized for their physic-chemical properties using conventional methods. The results obtained showed that with the increase of chitosan content in the composite results in decrease in its water absorption capacity. The FTIR and SEM studies have shown the composite nature of the films prepared. Ch-SG-AgNP and Ch-SG-AgNP-G composites were used as wound dressing materials in experimental wounds of rats. The healing pattern of the wounds was evaluated by planimetric studies, macroscopic observations, biochemical studies and histopathological observations. The results have shown faster healing pattern in the wounds treated with Ch-SG-AgNP and Ch-SG-AgNP-G composites compared to untreated control. This study suggests that Ch-SG-AgNP film may be a potential candidate as a dressing material for wound healing applications.
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39
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Karthikeyan K, Sekar S, Devi MP, Inbasekaran S, Lakshminarasaiah CH, Sastry TP. Fabrication of novel biofibers by coating silk fibroin with chitosan impregnated with silver nanoparticles. J Mater Sci Mater Med 2011; 22:2721-2726. [PMID: 22042460 DOI: 10.1007/s10856-011-4462-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 10/17/2011] [Indexed: 05/31/2023]
Abstract
Nanoparticle based agents often applied as coatings on biomaterials have shown promise in delivering the improved sterility against variety of microbes. In the present study, silk fibers (SF) were coated with chitosan impregnated with silver nanoparticles (Ag-C-SF). These Ag-C-SF fibers were characterized using scanning electron microscopy (SEM) with energy dispersive X-ray analysis, atomic force microscopy (AFM), Infra Red spectroscopy, Thermogravimetric Analysis and Microbiological assay techniques. AFM studies have confirmed the nano sized silver particles in chitosan solution; SEM pictures have exhibited the coating of chitosan along with silver nanoparticles on the silk fibroin. The modified fibers have also shown anti-microbial activity and improved thermal stability. The Ag-C-SF fibers may be explored as wound dressing and tendon reconstruction material in future.
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Affiliation(s)
- K Karthikeyan
- Bio-products Laboratory, Bioproducts Division, Central Leather Research Institute, Adyar, Chennai, India
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40
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Jasinski JP, Golen JA, Sekar S, Yathirajan HS, Naik N. 7-Meth-oxy-3,4-dihydro-naphthalen-1(2H)-one. Acta Crystallogr Sect E Struct Rep Online 2011; 67:o1646. [PMID: 21837050 PMCID: PMC3152045 DOI: 10.1107/s1600536811020174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 12/02/2022]
Abstract
In the title compound, C(11)H(12)O(2), the six-membered ketone ring fused to the 7-meth-oxy benzene ring adopts a slightly distorted envelope configuration with the central methyl-ene C atom being the flap. The crystal packing is stabilized by weak inter-molecular C-H⋯O and C-H⋯π inter-actions, which lead to supra-molecular layers in the bc plane.
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Affiliation(s)
- Jerry P. Jasinski
- Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA
| | - James A. Golen
- Department of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435-2001, USA
| | - S. Sekar
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
| | - H. S. Yathirajan
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
| | - Nagaraja Naik
- Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India
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41
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Yan M, Fresnais J, Sekar S, Chapel JP, Berret JF. Magnetic nanowires generated via the waterborne desalting transition pathway. ACS Appl Mater Interfaces 2011; 3:1049-1054. [PMID: 21401080 DOI: 10.1021/am101188y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report a simple and versatile waterborne synthesis of magnetic nanowires following the innovative concept of electrostatic "desalting transition". Highly persistent superparamagnetic nanowires are generated from the controlled assembly of oppositely charged nanoparticles and commercially available polyelectrolytes. The wires have diameters around 200 nm and lengths between 1 μm and 0.5 mm, with either positive or negative charges on their surface. Beyond, we show that this soft-chemistry assembly approach is a general phenomenon independent of the feature of the macromolecular building blocks, opening significant perspectives for the design of multifunctional materials.
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Affiliation(s)
- M Yan
- Matière et Systèmes Complexes, UMR 7057 CNRS, Université Denis Diderot Paris-VII , Bâtiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris, France
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42
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43
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44
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45
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Kathiravan A, Chandramohan M, Renganathan R, Sekar S. Photoinduced electron transfer from phycoerythrin to colloidal metal semiconductor nanoparticles. Spectrochim Acta A Mol Biomol Spectrosc 2009; 72:496-501. [PMID: 19083264 DOI: 10.1016/j.saa.2008.10.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 10/12/2008] [Accepted: 10/17/2008] [Indexed: 05/27/2023]
Abstract
Phycoerythrin is a water soluble pigment which absorbs in the visible region at 563 nm. The interaction of phycoerythrin with colloidal metal semiconductors was studied by absorption, FT-IR and fluorescence spectroscopy. Phycoerythrin adsorbed strongly on the surface of TiO(2) nanoparticles, the apparent association constant for the association between colloidal metal-TiO(2) nanoparticles and phycoerythrin was determined from fluorescence quenching data. The free energy change (DeltaG(et)) for electron transfer process has been calculated by applying Rehm-Weller equation.
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Affiliation(s)
- A Kathiravan
- School of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
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46
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Kathiravan A, Chandramohan M, Renganathan R, Sekar S. Spectroscopic studies on the interaction between phycocyanin and bovine serum albumin. J Mol Struct 2009. [DOI: 10.1016/j.molstruc.2008.09.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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47
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Kathiravan A, Chandramohan M, Renganathan R, Sekar S. Cyanobacterial chlorophyll as a sensitizer for colloidal TiO2. Spectrochim Acta A Mol Biomol Spectrosc 2009; 71:1783-1787. [PMID: 18678524 DOI: 10.1016/j.saa.2008.06.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Revised: 06/17/2008] [Accepted: 06/25/2008] [Indexed: 05/26/2023]
Abstract
Chlorophyll has been extracted from cyanobacteria. The adsorption of chlorophyll on the surface of colloidal TiO(2) through electrostatic interaction was observed. The apparent association constant (K(app)) of chlorophyll-TiO(2) obtained from absorption spectra is 3.78x10(4)M(-1). The K(app) value of chlorophyll-TiO(2) as determined from fluorescence spectra is 1.81x10(4)M(-1), which matches well with that determined from the absorption spectra changes. These data indicate that there is an interaction between chlorophyll and colloidal TiO(2) nanoparticle surface. The dynamics of photoinduced electron transfer from chlorophyll to the conduction band of colloidal TiO(2) nanoparticle has been observed and the mechanism of electron transfer has been confirmed by the calculation of free energy change (DeltaG(et)) by applying Rehm-Weller equation as well as energy level diagram. Lifetime measurements gave the rate constant (k(et)) for electron injection from the excited state chlorophyll into the conduction band of TiO(2) is 4.2x10(8)s(-1).
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Affiliation(s)
- A Kathiravan
- School of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
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Sastry TP, Sundaraseelan J, Swarnalatha K, Liji Sobhana SS, Uma Makheswari M, Sekar S, Mandal AB. Growth of hydroxyapatite on physiologically clotted fibrin capped gold nanoparticles. Nanotechnology 2008; 19:245604. [PMID: 21825816 DOI: 10.1088/0957-4484/19/24/245604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The growth of hydroxyapatite (HAp) on physiologically clotted fibrin (PCF)-gold nanoparticles is presented for the first time by employing a wet precipitation method. Fourier transform infrared (FTIR) spectroscopy confirmed the characteristic functionalities of PCF and HAp in the PCF-Au-HAp nanocomposite. Scanning electron microscopy (SEM) images have shown cuboidal nanostructures having a size in the range of 70-300 nm of HAp, whereas 2-50 nm sized particles were visualized in high-resolution transmission electron microscopy (TEM). Energy-dispersive x-ray (EDX) and x-ray diffraction (XRD) studies have confirmed the presence of HAp. These results show that gold nanoparticles with PCF acted as a matrix for the growth of HAp, and that PCF-Au-HAp nanocomposite is expected to have better osteoinductive properties.
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Kumar MM, Jeyabalachandran M, Sekar S. Intrahepatic cyst--a complication of ventriculoperitoneal shunt. J Indian Med Assoc 1995; 93:403. [PMID: 9053432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- M M Kumar
- Department of Neurology and Neurosurgery, Madurai Medical College and Government Rajaji Hospital
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