IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Bioactive glass incorporated dressing matrix for rapid hemostatic action with antibacterial activity
No full textUncontrolled bleeding stands as a leading cause of preventable death in both civilian trauma and military battlefield scenarios. Existing hemostatic dressings like HemCon, Celox, and QuickClot, often lack instant hemostasis at the bleeding site and may have biodegradability and exothermic issues. To address the above in this communication, we have synthesized a hemostatic glass (acronym AlBG, CaO-SiO2 system, incorporated with Al2O3 and ZnO) by sol gel route and carried out detail physicochemical characterizations, e.g., XRD, FESEM, FTIR, BET and particle size analysis etc. The AlBG of particle size range 140-253 nm was incorporated into the nonwoven surgical cotton gauze to obtain AlBGscg. In vitro biological assays including cytocomtability, hemocompatibility assays of the above coated gauze was undertaken using NIH3T3 of which, the later showed optimum hemocompatibility with <6 % lysis of red blood cells. Potent antibacterial action on both gram positive and gram negative strains were obtained with significant zone of inhibition of 17 +/- 0.34 mm and 16 +/- 0.56 mm, respectively. Importantly, significant reduction of the clotting time (31.81 +/- 0.12 % for P time and 33.3 +/- 0.23 % for aPTT) compared to the control group, indicated activation of both intrinsic and extrinsic coagulation pathways. Scanning electron microscope (SEM) images exhibited an enhanced in vitro blood clot formation in case of AlBGscg in comparison to the control (uncoated surgical cotton gauze), visually. Additionally, a noticeable reduction of similar to 30 % in the time required for the blood clot formation, in case of AlBGscg, was observed. The in vivo hemostatic potential of AlBGscg was evaluated in Wistar rats through femoral artery injury and was compared with commercially available surgical cotton gauze. The results demonstrated substantial reduction in the time required for hemostasis (approximately 50 % reduction), a lower amount of blood loss (7.33 % with AlBGscg compared to 22.31 % with surgical cotton gauze), and importantly, there were no incidents of re -bleeding observed with AlBGscg, highlighting its promise as a candidate for effective hemostasis
Special Application of Bioactive Glass as Active Ingredient in Woundcare and Hemostasis
No full textRecently, bioactive glass (BG) has emerged as a promising solution for treating injuries such as diabetic and venous ulcers. BG release the therapeutic ions that helps in fibrin clot formation by aid in platelet aggregation, supporting the coagulation cascade and helping in the regeneration of
soft tissue. In the Part A of this thesis, we synthesized a binary glass composition (named, AgBG)containing varying mol% of SiO2, CaO, B2O3, and Ag2O using the sol-gel technique, followed by electrospinning with an FDA-approved polymer to fabricate a fibrous matrix named ABGmnf based wound care matrix. We then conducted various material characterization techniques including XRD, FTIR, TG-DSC, FESEM, BET, angle of repose, zeta potential, solubility assessment, and mechanical property testing. Biological studies included in vitro
cytocompatibility, immunofluorescence staining for cellular proliferation and morphology, 2D wound healing assays, and antibacterial experiments to estimate zone of inhibition (ZOI) and determines minimum inhibitory concentration (MIC) using gram positive and gram negative strains. The in vitro material characterizations and biological studies confirmed the successful fabrication of ABGmnf based wound care matrix, its cytocompatibility, and antibacterial activity. Subsequently, in vivo pharmacokinetic and biodistribution studies along with
biocompatibility study by assessing IL-6 and TNF-α confirmed its safety profile. This was followed by in vivo wound healing assay, which exhibited fast closure of wound, and histological
assessment of various vital organs. These findings suggest that compositions like AgBG as ABGmnf based wound care matrix have great potential in the wound care market and could pave
the way for new directions in tissue engineering.
In the Part B of the thesis, we report a unique composition of bioactive glass, 70 SiO2: (30-x-y) CaO: x.Al2O3: y.ZnO, where x=10-18 mole% and y= 0-8 mole%, exhibiting haemostatic property as well as antibacterial activity. The as-prepared glass was characterized using XRD,SEM-EDX, FTIR, BET and TG-DSC along with in vitro degradation study and biological studies e.g., cytocompatibility, haemocompatibility, in vitro thrombus formation, in vitro blood absorption capacity, blood coagulation assays (PT, aPTT), erythrocyte adhesion assay,
measuring blood clotting index (BCI), in vitro antibacterial assay against S. aureus as well as invivo acute dermal toxicity followed by histopathological analysis) and in vivo hemostasis efficacy were undertaken. The novel bioactive glass composition exhibits promises to be an efficient haemostatic agent with antibacterial activity
Cobalt Containing Antimicrobial Bioactive Glass Coated Urinary Catheter Towards Management Of Catheter Associated Urinary Tract Infection (CAUTI): Significant In Vitro Characterizations
No full textUncontrolled bleeding stands as a leading cause of preventable death in both civilian trauma and military battlefield scenarios. Existing hemostatic dressings like HemCon, Celox, and QuickClot, often lack instant hemostasis at the bleeding site and may have biodegradability and exothermic issues. To address the above in this communication, we have synthesized a hemostatic glass (acronym AlBG, CaO-SiO2 system, incorporated with Al2O3 and ZnO) by sol gel route and carried out detail physicochemical characterizations, e.g., XRD, FESEM, FTIR, BET and particle size analysis etc. The AlBG of particle size range 140–253 nm was incorporated into the nonwoven surgical cotton gauze to obtain AlBGscg. In vitro biological assays including cytocomtability, hemocompatibility assays of the above coated gauze was undertaken using NIH3T3 of which, the later showed optimum hemocompatibility with <6 % lysis of red blood cells. Potent antibacterial action on both gram positive and gram negative strains were obtained with significant zone of inhibition of 17 ± 0.34 mm and 16 ± 0.56 mm, respectively. Importantly, significant reduction of the clotting time (31.81 ± 0.12 % for P time and 33.3 ± 0.23 % for aPTT) compared to the control group, indicated activation of both intrinsic and extrinsic coagulation pathways. Scanning electron microscope (SEM) images exhibited an enhanced in vitro blood clot formation in case of AlBGscg in comparison to the control (uncoated surgical cotton gauze), visually. Additionally, a noticeable reduction of ∼30 % in the time required for the blood clot formation, in case of AlBGscg, was observed. The in vivo hemostatic potential of AlBGscg was evaluated in Wistar rats through femoral artery injury and was compared with commercially available surgical cotton gauze. The results demonstrated substantial reduction in the time required for hemostasis (approximately 50 % reduction), a lower amount of blood loss (7.33 % with AlBGscg compared to 22.31 % with surgical cotton gauze), and importantly, there were no incidents of re-bleeding observed with AlBGscg, highlighting its promise as a candidate for effective hemostasis
Effect of Nd2O3 concentration on crystallization mechanism and third-order optical nonlinearity of lanthanide-titanium-tellurite glass and glass-ceramics
No full textRare-earth (RE) doped transparent tellurite glass-ceramics (GCs) embedded with “anti-glass” crystallites not only exhibit superior emission properties, can also be a potential medium for nonlinear optical (NLO) applications. Both of these properties depend on their transparency. Keeping this in view, we aimed to elucidate the effect of Nd3+ion concentration(0.5-2 mol%) on crystallization mechanism of lanthanum-gadolinium-titanium-tellurite (LGTT) glass in retaining the transparency, and NLO properties.XRD reveals the precipitation of (La/Nd)2T6O15 and Gd2Te6O15“anti-glass” crystallites upon ceramization of these glasses.Particle size-dependent DSC confirms competition between the growth of these two crystalline phasesat higher Nd3+ concentration that aids in controlling crystal growth.The FE-SEM microstructures demonstrate a change in morphology of the crystallites from rectangular (1.5 μm) to spherical (120 nm) with increasing Nd2O3 concentration from 0.5→2 mol% and thereby retaining optical transparency (12%→55%) in GCs. Photoluminescence spectra reveal maximum emissionintensity for 1 mol% of Nd2O3 doped glass, however, lifetime is maximum (156 μs) for 0.5 % Nd2O3 doping. This study also discloses an enhancement of third-order NLO properties as a function of Nd2O3 concentration in LGTT glasses under femtosecond laser excitation at 800-1200 nmdue to resonant nonlinearity. Emission intensity and NLO responses is increased in the GCs compared to their parent glasses.Maximum nonlinearabsorption coefficient (α2) of 4.986×10-10 m/W and nonlinear refractive index (n2) of 3.115× 10-17 m2/W has been obtained from LGTT-Nd2(GC-36h) GCs at 800 nm. GCsexhibit an optical limiting threshold of 4.14 mJ/cm2 suggesting its great potential for intense radiation shielding
Growth of Ge on silicon-on-insulator wafer by plasma enhanced chemical vapor deposition and fabrication of microline photodetector using the Ge layer
No full textA Ge top layer of thickness similar to 1.2 mu m was grown on the top Si of a silicon -on -insulator (SOI) wafer by plasmaenhanced chemical vapor deposition (PECVD) technique followed by rapid thermal annealing (RTA) makes this a GeSOI wafer. The top active Ge layer on RTA recrystallizes into a compact layer of Ge nanocrystals with lattice constants close to those of the Ge single crystal enabling device fabrication and a partially suspended Ge microline photodetector was fabricated that can show adequate photo gain. It was established through simulation that the partial suspension of the microline is necessary to isolate the microlines from the bulk of the wafer which inhibits carrier recombination by the underlying oxide layer
Ambient formation of high pressure Ag2Si2O5 and non-stoichiometric Ag0.3Al0.7 alloy under confinement
No full textWe report results of Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Analysis of X-rays (EDAX), X-ray Photoelectron Spectroscopy (XPS), X-ray Reflectivity (XRR), and X-ray Diffraction (XRD) and residual stress measurement studies of Ag-silica composite films on Al(001) co-deposited from precursors and spin-coated at different frequencies under ambient conditions. FESEM and EDAX show Ag nanoparticle formation, and XRD, XPS, and XRR show Ag0.3Al0.7 alloy and Ag-rich silicate Ag2Si2O5 formation in all samples. The alloy is non-stoichiometric and non-equilibrium, while the silicate forms at high oxygen pressure. XRR shows the presence of three layers, nanoparticles on top, silicate in the middle, and alloy at the bottom, on an Ag-doped Al substrate. Film thickness decreases exponentially with frequency. Individual layers increase in crystal domain size with a frequency of 3000 rpm when the silicate layer thins below unit cell thickness and the growth has a two-dimensional preference. Our results suggest total confinement by film thinning and local confinement from the Ag nanolayer. Residual stress measurements on the films deposited at 500 and 5000 rpms show a gradual increase in the tensile stress. The increase in spinning frequency reveals the formation of high pressure ambience
An approach to surface electron density-sensing property correlation in non-stoichiometric boron carbide
No full textThe key to most surface phenomena lies in the surface electron density. Particularly, it is the electron density distribution over the surface that primarily controls the overall interaction of the material with the external environment, say in processes like heterogeneous catalysis. Hence, a precise understanding of surface electron density is essential to understand and design improved surface active materials for catalysis and sensing. Surface structure has been determined primarily using surface sensitive techniques like high-energy surface x-ray diffraction (XRD), the crystal truncation rod scattering method, low-energy electron diffraction, scanning transmission electron microscopy, and grazing incidence small angle x-ray scattering. In this work, using aspherical electron density models of crystal structures in different molecular and extended solids, we show a convenient and complementary way of determining high-resolution experimental surface electron density distribution from conventional bulk x-ray diffraction data. The usefulness of our method has been validated by the surface functionality of boron carbide. While certain surfaces in boron carbide show the presence of substantial electron deficient centers, they are absent in others. Based on that, a new surface property of boron carbide has been inferred and has also been validated by chemiresistive gas sensing experiments. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/)
Flexible ceramic based 'paper separator' with enhanced safety for high performance lithium-ion batteries: Probing the effect of ceramics impregnation on electrochemical performances
No full textCellulose is now considered as an appealing environment friendly material for the development of sustainable separators for rechargeable batteries. This study thus aims to develop high performance paper based ceramic separators with superior electrolyte wettability (>170 ), high thermal stability (>200 °C) and excellent flame safety. While developing paper based ceramic separator, extensive studies are carried out to understand thenature and functionality of different nano-structured ceramic materials (Al2O3, BaTiO3 and ZrO2) impregnated in paper matrix. Nano-ZrO2 facilitates an effective pathway for Li +-ion transport (tLi+ = 0.51), whereas BaTiO3 and Al2O3 ceramics show moderate Li +-ion transport properties (tLi+ of 0.29 and 0.30 respectively). Electrochemical Impedance Spectroscopy (EIS) measurement clearly reveals that ZrO2 exhibits more interfacial compatibility with the electrodes (MCMB and LiNi1/3Mn1/3Co1/3O2) compared to the other two ceramic separators during full cell operation. The developed paper separators show excellent electrochemical properties in terms of cycling (tested 300 cycles), multi-electrode compatibility and rate capabilities at different current densities of 0.1 1.2 mAcm 2. The pre- and post-electrochemical EIS data reveal that ZrO2 based impregnation offers significantly lower charge transfer resistance compared to the other two separators. The study thus demonstrates a real promise for its successful application in Li-ion battery towards achieving sustainability and safety
Reverse Polarizability of Rare Earth Ions (La3+, Gd3+, Lu3+, Y3+) in Tellurite Glasses and Glass Ceramics for Optical Limiting
No full textAll-optical modulation using inherent third-order optical nonlinearity of a medium has garnered considerable interest in photonics and optoelectronics. Herein, nonlinear optical (NLO) properties of tellurite glasses and glass ceramics (GCs) containing four different rare earths (RE = La, Gd, Lu, and Y) have been deliberated in near-infrared regions under an ultrafast regime. The La-based glass exhibits ∼10 times higher nonlinear refraction (n2) and absorption (α2) than reported NLO materials. The NLO susceptibility [χ(3)] trend in the studied glasses is La > Gd > Lu > Y, matching with RE3+ polarizability. Furthermore, Ln2Te6O15 nanocrystallite-embedded transparent GCs exhibit a larger NLO coefficient due to the enhanced local field from oxygen vacancies in crystallites. Interestingly, the trend of χ(3) in GCs follows the sequence of Y > Lu > Gd > La, precisely opposite to the glasses. This observation challenges the general polarizability approach of RE3+ ions, emphasizing that quadratic hyperpolarizability of RE3+ is pivotal for NLO properties of GCs. Among the studied matrices, Y-containing GCs showed the lowest optical limiting (OL) threshold (5.4 mJ/cm2 at 800 nm), much lower than those of the reported NLO materials, suggesting its potential as a femtosecond NIR-laser safety material. A combination of large α2 and n2 from the studied matrices indicates their advantage for harmonic generation, potentially aiding in the design of ultrafast signal processing devices
Visible-Light-Assisted Photocatalytic CO2 Reduction and N2-Fixation over TiO2 Covalent Organic Framework Heterojunction Photocatalyst
No full textThe potential applications of covalent organic frameworks (COFs) in the field of photocatalysis are constrained by the fast recombination rate of the photoinduced carriers and their limited visible light absorption capacity. Design of Z-scheme heteroframework utilizing COFs is believed to be an innovative and effective approach to assist the charge separation efficacy and improve the photocatalytic activity of the materials. Herein, the imine-based 2D COF (referred to as TP-TAPM COF) and TiO2 were effectively coupled together by covalent bonding using a simple solvothermal approach to construct a novel heterojunction TiO2/TP-TAPM photocatalyst. The resulting TiO2/TP-TAPM heterostructure was well characterized by a sequence of experimentations to investigate the compositional, structural, and morphological characteristics. Interestingly, the as-synthesized hybrid photocatalyst was applied for the first time to efficiently reduce CO2 to CH3OH as well as N-2 to NH3 under visible light illumination at ambient reaction conditions without the need of specific organic scavengers and cocatalysts. Using the TiO2/TP-TAPM hybrid photocatalyst (8 mg), a substantially higher yield of methanol was produced with a formation rate of 281.25 mmol g(cat)(-1) h(-1) after 4 h of visible light irradiation. Whereas, the generation rate of NH4+ was found to be 747 mu mol L-1 h(-1) after irradiation for 5 h using 5 mg of as-synthesized heterojunction photocatalyst. The development of a covalent interaction in the 2D-2D heterojunction between COF and TiO2, mostly as a result of their close interfacial contact, can be attributed to the greatly improved photocatalytic efficiency. Hence, the constructed 2D-2D-layered structure offers a high contact area, which substantially facilitates the separation and transportation of photogenerated charge carriers, boosts light absorption, and enhances photocatalytic activity. This work sheds light on the development of a promising approach for the artful integration of organic materials (COFs) with inorganic semiconductors into a single hybrid with a 2D-2D interface as effective photocatalysts for CO2 reduction as well as N-2 fixation, holding significant implications for extensions to other material systems