Biodegradability of graphene is one of the fundamental parameters determining the fate of this material in vivo. Two types of aqueous dispersible graphene, corresponding to single‐layer (SLG) and ...few‐layer graphene (FLG), devoid of either chemical functionalization or stabilizing surfactants, were subjected to biodegradation by human myeloperoxidase (hMPO) mediated catalysis. Graphene biodegradation was also studied in the presence of activated, degranulating human neutrophils. The degradation of both FLG and SLG sheets was confirmed by Raman spectroscopy and electron microscopy analyses, leading to the conclusion that highly dispersed pristine graphene is not biopersistent.
Not biopersistent: Two types of aqueous dispersible graphene, corresponding to single layer (SLG) and few layer graphene (FLG), devoid of either chemical functionalization or stabilizing surfactants, were subjected to biodegradation. Graphene can be degraded by human myeloperoxidase secreted by activated neutrophils, indicating that this material is not biopersistent.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract Carbon-based nanomaterials including carbon nanotubes, graphene oxide, fullerenes and nanodiamonds are potential candidates for various applications in medicine such as drug delivery and ...imaging. However, the successful translation of nanomaterials for biomedical applications is predicated on a detailed understanding of the biological interactions of these materials. Indeed, the potential impact of the so-called bio-corona of proteins, lipids, and other biomolecules on the fate of nanomaterials in the body should not be ignored. Enzymatic degradation of carbon-based nanomaterials by immune-competent cells serves as a special case of bio-corona interactions with important implications for the medical use of such nanomaterials. In the present review, we highlight emerging biomedical applications of carbon-based nanomaterials. We also discuss recent studies on nanomaterial ‘coronation’ and how this impacts on biodistribution and targeting along with studies on the enzymatic degradation of carbon-based nanomaterials, and the role of surface modification of nanomaterials for these biological interactions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Over the past few decades, inorganic nanoparticles, which exhibit significantly distinct physical, chemical and biological properties from their bulk counterpart's, have elicited much interest. ...Discoveries in the past decade have demonstrated that the electromagnetic, optical and catalytic properties of noble-metal nanoparticles such as gold, silver and platinum, are strongly influenced by shape and size. This has motivated an upsurge in research on the synthesis routes that allow better control of shape and size for various nano-biotechnological applications. Biomedical applications of metal nanoparticles have been dominated by the use of nanobioconjugates that started in 1971 after the discovery of immunogold labeling by Faulk and Taylor. Currently metal-based nanoconjugates are used in various biomedical applications such as probes for electron microscopy to visualize cellular components, drug delivery (vehicle for delivering drugs, proteins, peptides, plasmids, DNAs, etc), detection, diagnosis and therapy (targeted and non-targeted). However biological properties of bare-metal (naked) nanoparticles have remained largely unexplored. Therefore, in this review we discuss the novel biological properties and applications of three most widely used metal nanoparticles, namely, the nanoparticles of gold, silver and platinum. We describe the novel properties and use of these nanoparticles in angiogenesis and cancer related disorders.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The rapid growth of electronic devices, their subsequent obsolescence and disposal has resulted in electronic waste (e-waste) being one of the fastest increasing waste streams worldwide. The main ...component of e-waste is printed circuit boards (PCBs), which contain substantial quantities of precious metals in concentrations significantly higher than those typically found in corresponding ores. The high value and limited reserves of minerals containing these metals makes urban mining of precious metals very attractive. This article is focused on the concentration and recovery of precious metals during pyro-metallurgical recycling of waste PCBs. High temperature pyrolysis was carried out for ten minutes in a horizontal tube furnace in the temperature range 800-1350°C under Argon gas flowing at 1L/min. These temperatures were chosen to lie below and above the melting point (1084.87°C) of copper, the main metal in PCBs, to study the influence of its physical state on the recovery of precious metals. The heat treatment of waste PCBs resulted in two different types of solid products, namely a carbonaceous non-metallic fraction (NMFs) and metallic products, composed of copper rich foils and/or droplets and tin-lead rich droplets and some wires. Significant proportions of Ag, Au, Pd and Pt were found concentrated within two types of metallic phases, with very limited quantities retained by the NMFs. This process was successful in concentrating several precious metals such as Ag, Au, Pd and Pt in a small volume fraction, and reduced volumes for further processing/refinement by up to 75%. The amounts of secondary wastes produced were also minimised to a great extent. The generation of precious metals rich metallic phases demonstrates high temperature pyrolysis as a viable approach towards the recovery of precious metals from e-waste.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
A controlled and up-scalable biosynthetic route to nanocrystalline silver particles with well-defined morphology using cell-free aqueous filtrate of a non-pathogenic and commercially viable ...biocontrol agent Trichoderma asperellum is being reported for the first time. A transparent solution of the cell-free filtrate of Trichoderma asperellum containing 1 mM AgNO(3) turns progressively dark brown within 5 d of incubation at 25 °C. The kinetics of the reaction was studied using UV-vis spectroscopy. An intense surface plasmon resonance band at ∼410 nm in the UV-vis spectrum clearly reveals the formation of silver nanoparticles. The size of the silver particles using TEM and XRD studies is found to be in the range 13-18 nm. These nanoparticles are found to be highly stable and even after prolonged storage for over 6 months they do not show significant aggregation. A plausible mechanism behind the formation of silver nanoparticles and their stabilization via capping has been investigated using FTIR and surface-enhanced resonance Raman spectroscopy.
Lithium metal, although attracting renewed interest for the next revolution in energy storage, continues to be challenged with the detrimental dendrite formation. Recent experimental reports have ...demonstrated the contrasting impact of thermal attributes on the electrodeposition morphology, showcasing the alleviation and/or aggravation of dendrite formation. Herein, we present a comprehensive discourse to discern the thermally activated physical mechanisms governing lithium electrodeposition morphology. We report that the synergistic effect of enhanced electrolyte transport and surface self-diffusion under a uniform thermal field (∼75 °C) enables adequate dendrite suppression, even at high reaction rates. However, in contrast to this, a localization of the thermal field substantially increases the exchange current density of the confined region, instigating the growth of needle dendrites. Based on our mesoscale analysis, we demarcate safety limits for such an event, beyond which dendrite growth is inevitably triggered. Therefore, though the operational strategy of elevating the cell temperature promises to resolve the challenge of stable electrodeposition, it comes along with the caveat. This fundamental study provides a detailed insight into underlying electrochemical-thermal complexations, critical to the performance and safety of metal-based rechargeable batteries.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract The animal model deals with the species other than the human, as it can imitate the disease progression, its’ diagnosis as well as a treatment similar to human. Discovery of a drug and/or ...component, equipment, their toxicological studies, dose, side effects are in vivo studied for future use in humans considering its’ ethical issues. Here lies the importance of the animal model for its enormous use in biomedical research. Animal models have many facets that mimic various disease conditions in humans like systemic autoimmune diseases, rheumatoid arthritis, epilepsy, Alzheimer’s disease, cardiovascular diseases, Atherosclerosis, diabetes, etc., and many more. Besides, the model has tremendous importance in drug development, development of medical devices, tissue engineering, wound healing, and bone and cartilage regeneration studies, as a model in vascular surgeries as well as the model for vertebral disc regeneration surgery. Though, all the models have some advantages as well as challenges, but, present review has emphasized the importance of various small and large animal models in pharmaceutical drug development, transgenic animal models, models for medical device developments, studies for various human diseases, bone and cartilage regeneration model, diabetic and burn wound model as well as surgical models like vascular surgeries and surgeries for intervertebral disc degeneration considering all the ethical issues of that specific animal model. Despite, the process of using the animal model has facilitated researchers to carry out the researches that would have been impossible to accomplish in human considering the ethical prohibitions.
Despite progress in solid-state battery engineering, our understanding of the chemo-mechanical phenomena that govern electrochemical behaviour and stability at solid-solid interfaces remains limited ...compared to at solid-liquid interfaces. Here, we use operando synchrotron X-ray computed microtomography to investigate the evolution of lithium/solid-state electrolyte interfaces during battery cycling, revealing how the complex interplay among void formation, interphase growth and volumetric changes determines cell behaviour. Void formation during lithium stripping is directly visualized in symmetric cells, and the loss of contact that drives current constriction at the interface between lithium and the solid-state electrolyte (Li
SnP
S
) is quantified and found to be the primary cause of cell failure. The interphase is found to be redox-active upon charge, and global volume changes occur owing to partial molar volume mismatches at either electrode. These results provide insight into how chemo-mechanical phenomena can affect cell performance, thus facilitating the development of solid-state batteries.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
Lithium metal is an attractive negative electrode material for rechargeable lithium batteries because of its light weight and high electronegative redox potential. However, dendritic deposition of ...lithium during charging poses a safety concern. During discharging, some of the lithium may strip away from the electrode as the root of the dendrite is electrodissolved. This is referred to as dead lithium since it is not electrochemically active, which may result in low coulombic efficiency. In this work, a comprehensive understanding of the interface evolution leading to the formation of dead lithium is presented based on a mechanism-driven probabilistic analysis. A non-dendritic interface morphology is obtained under reaction and ionic transport controlled scenarios. Otherwise, this may evolve into mossy, dendritic, whisker or needle-like structures with the main characteristic being the propensity for undesirable vertical growth. During discharging, a pitted interface may be formed along with bulk dissolution. Surface diffusion is a key determinant controlling the extent of dead lithium formation, including a higher probability of the same when the effect of surface diffusion is comparable to that of ionic diffusion in the electrolyte and interface reaction.
Anode potential controlled charging prevents lithium plating Rangarajan, Sobana P; Barsukov, Yevgen; Mukherjee, Partha P
Journal of materials chemistry. A, Materials for energy and sustainability,
01/2020, Volume:
8, Issue:
26
Journal Article
Peer reviewed
We report a novel anode potential controlled charging strategy for lithium-ion cells which eliminates lithium plating under most aggressive conditions, such as at low temperatures. This is applicable ...for lithium-ion cells with a graphite anode irrespective of the form factor, capacity or cathode chemistry. This new charging strategy leads to a seven-fold increase in cycle life and a concomitant improvement in the electrochemical performance. Conventional charging shows copious lithium plating swiftly followed by cell failure due to accelerated increase in the anode resistance. The anode potential controlled charging strategy, based on a three-electrode cell construction, exhibits minimal increase in the anode resistance and shows no signs of lithium plating in operational extremes. Optical micrographs and high-resolution scanning electron images confirm that the graphite anode in the conventionally charged Li-ion cell undergoes significant loss in porosity resulting in massive underlithiation and dramatic capacity fading. The degradation rate in the anode is decelerated in anode potential controlled charging by ensuring that plating potential is not reached and improving ion transport in the anode even at low temperatures due to the absence of decomposition products that would have formed during plating.
We report a novel anode potential controlled charging strategy for lithium-ion cells which eliminates lithium plating under most aggressive conditions, such as at low temperatures.
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