Graphene-based materials (GBMs) are emerging as attractive materials for biomedical applications. Understanding how these materials are perceived by and interact with the immune system is of ...fundamental importance. Phagocytosis is a major mechanism deployed by the immune system to remove pathogens, particles, and cellular debris. Here, we discuss recent studies on the interactions of GBMs with different phagocytic cells, including macrophages, neutrophils, and dendritic cells. The importance of assessing GBMs for endotoxin contamination is discussed as this may skew results. We also explore the role of the bio-corona for interactions of GBMs with immune cells. Finally, we highlight recent evidence for direct plasma membrane interactions of GBMs.
Neutrophils were previously shown to digest oxidized carbon nanotubes through a myeloperoxidase (MPO)-dependent mechanism, and graphene oxide (GO) was found to undergo degradation when incubated with ...purified MPO, but there are no studies to date showing degradation of GO by neutrophils. Here we produced endotoxin-free GO by a modified Hummers' method and asked whether primary human neutrophils stimulated to produce neutrophil extracellular traps or activated to undergo degranulation are capable of digesting GO. Biodegradation was assessed using a range of techniques including Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and mass spectrometry. GO sheets of differing lateral dimensions were effectively degraded by neutrophils. As the degradation products could have toxicological implications, we also evaluated the impact of degraded GO on the bronchial epithelial cell line BEAS-2B. MPO-degraded GO was found to be non-cytotoxic and did not elicit any DNA damage. Taken together, these studies have shown that neutrophils can digest GO and that the biodegraded GO is non-toxic for human lung cells.
A stable anode‐free all‐solid‐state battery (AF‐ASSB) with sulfide‐based solid‐electrolyte (SE) (argyrodite Li6PS5Cl) is achieved by tuning wetting of lithium metal on “empty” copper ...current‐collector. Lithiophilic 1 µm Li2Te is synthesized by exposing the collector to tellurium vapor, followed by in situ Li activation during the first charge. The Li2Te significantly reduces the electrodeposition/electrodissolution overpotentials and improves Coulombic efficiency (CE). During continuous electrodeposition experiments using half‐cells (1 mA cm−2), the accumulated thickness of electrodeposited Li on Li2Te–Cu is more than 70 µm, which is the thickness of the Li foil counter‐electrode. Full AF‐ASSB with NMC811 cathode delivers an initial CE of 83% at 0.2C, with a cycling CE above 99%. Cryogenic focused ion beam (Cryo‐FIB) sectioning demonstrates uniform electrodeposited metal microstructure, with no signs of voids or dendrites at the collector‐SE interface. Electrodissolution is uniform and complete, with Li2Te remaining structurally stable and adherent. By contrast, an unmodified Cu current‐collector promotes inhomogeneous Li electrodeposition/electrodissolution, electrochemically inactive “dead metal,” dendrites that extend into SE, and thick non‐uniform solid electrolyte interphase (SEI) interspersed with pores. Density functional theory (DFT) and mesoscale calculations provide complementary insight regarding nucleation‐growth behavior. Unlike conventional liquid‐electrolyte metal batteries, the role of current collector/support lithiophilicity has not been explored for emerging AF‐ASSBs.
Lithiophilic Li2Te is synthesized by exposing the collector to tellurium vapor, followed by in situ Li activation. The Li2Te significantly reduces the electrodeposition/electrodissolution overpotentials and improves Coulombic efficiency. An anode‐free all‐solid‐state battery employing a sulfide‐based solid‐electrolyte (argyrodite Li6PS5Cl) with NMC811 cathode delivers an initial CE of 83% at 0.2C, with a cycling CE above 99%.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Crohn's disease (CD) results from a complex interplay between host genetic factors and endogenous microbial communities. In the current study, we used Ion Torrent sequencing to characterize the gut ...bacterial microbiota (bacteriome) and fungal community (mycobiome) in patients with CD and their nondiseased first-degree relatives (NCDR) in 9 familial clusters living in northern France-Belgium and in healthy individuals from 4 families living in the same area (non-CD unrelated NCDU). Principal component, diversity, and abundance analyses were conducted, and CD-associated inter- and intrakingdom microbial correlations were determined. Significant microbial interactions were identified and validated using single- and mixed-species biofilms. CD and NCDR groups clustered together in the mycobiome but not in the bacteriome. Microbiotas of familial (CD and NCDR) samples were distinct from those of nonfamilial (NCDU) samples. The abundance of Serratia marcescens and Escherichia coli was elevated in CD patients, while that of beneficial bacteria was decreased. The abundance of the fungus Candida tropicalis was significantly higher in CD than in NCDR (P = 0.003) samples and positively correlated with levels of anti-Saccharomyces cerevisiae antibodies (ASCA). The abundance of C. tropicalis was positively correlated with S. marcescens and E. coli, suggesting that these organisms interact in the gut. The mass and thickness of triple-species (C. tropicalis plus S. marcescens plus E. coli) biofilm were significantly greater than those of single- and double-species biofilms. C. tropicalis biofilms comprised blastospores, while double- and triple-species biofilms were enriched in hyphae. S. marcescens used fimbriae to coaggregate or attach with C. tropicalis/E. coli, while E. coli was closely apposed with C. tropicalis Specific interkingdom microbial interactions may be key determinants in CD.
Here, we characterized the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in multiplex families with CD and healthy relatives and defined the microbial interactions leading to dysbiosis in CD. We identified fungal (Candida tropicalis) and bacterial (Serratia marcescens and Escherichia coli) species that are associated with CD dysbiosis. Additionally, we found that the level of anti-Saccharomyces cerevisiae antibodies (ASCA; a known CD biomarker) was associated with the abundance of C. tropicalis We also identified positive interkingdom correlations between C. tropicalis, E. coli, and S. marcescens in CD patients and validated these correlations using in vitro biofilms. These results provide insight into the roles of bacteria and fungi in CD and may lead to the development of novel treatment approaches and diagnostic assays.
A three-electrode cell can be a useful tool for measuring electrode-level and cell-level electrochemical characteristics, such as the impedance response and potential variations in lithium-ion cells. ...In this paper, a reliable three-electrode coin cell setup is introduced, which improves the stability and accuracy of electrochemical measurements by modifying the electrode alignment and employing Li4Ti5O12 as a reference electrode. An important highlight is the ability to obtain impedance evolution characteristics at different depth of discharge (DOD) for an individual electrode and the full cell based on both the frequency response analysis and the carrier function Laplace transform characteristics. The reliability of the proposed modified three-electrode coin cell setup has been validated by analyzing the impedance response of symmetric and full cells, and the voltage profiles of the full cell along with the positive/negative electrode contributions. The importance of the resistance contributions from the negative and positive electrodes to the full cell impedance evolution at different DOD is highlighted.
Nanomaterials may be contaminated with bacterial endotoxin during production and handling, which may confound toxicological testing of these materials, not least when assessing for immunotoxicity. In ...the present study, we evaluated the conventional Limulus amebocyte lysate (LAL) assay for endotoxin detection in graphene based material (GBM) samples, including graphene oxide (GO) and few-layered graphene (FLG). Our results showed that some GO samples interfered with various formats of the LAL assay. To overcome this problem, we developed a TNF-α expression test (TET) using primary human monocyte-derived macrophages incubated in the presence or absence of the endotoxin inhibitor, polymyxin B sulfate, and found that this assay, performed with non-cytotoxic doses of the GBM samples, enabled unequivocal detection of endotoxin with a sensitivity that is comparable to the LAL assay. FLG also triggered TNF-α production in the presence of the LPS inhibitor, pointing to an intrinsic pro-inflammatory effect. Finally, we present guidelines for the preparation of endotoxin-free GO, validated by using the TET.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recent years have witnessed an explosion of research and development efforts in the area of polymer electrolyte fuel cells (PEFC), perceived as the next generation clean energy source for automotive, ...portable and stationary applications. Despite significant progress, a pivotal performance/durability limitation in PEFCs centers on two-phase transport and mass transport loss originating from suboptimal liquid water transport and flooding phenomena. Liquid water blocks the porous pathways in the gas diffusion layer (GDL) and the catalyst layer (CL), thus hindering oxygen transport from the flow field to the electrochemically actives sites in the catalyst layer. Different approaches have been examined to model the underlying transport mechanisms in the PEFC with different levels of complexities. Due to the macroscopic nature, these two-phase models fail to resolve the underlying structural influence on the transport and performance. Mesoscopic modeling at the pore-scale offers great promise in elucidating the underlying structure-transport-performance interlinks in the PEFC porous components. In this article, a systematic review of the recent progress and prospects of pore-scale modeling in the context of two-phase transport in the PEFC is presented. Specifically, the efficacy of lattice Boltzmann (LB), pore morphology (PM) and pore network (PN) models coupled with realistic delineation of microstructures in fostering enhanced insight into the underlying liquid water transport in the PEFC GDL and CL is highlighted.
A key performance limitation in polymer electrolyte fuel cells (PEFC), manifested in terms of mass transport loss, originates from liquid water transport and resulting flooding phenomena in the ...constituent components. Liquid water covers the electrochemically active sites in the catalyst layer (CL) rendering reduced catalytic activity and blocks the available pore space in the porous CL and fibrous gas diffusion layer (GDL) resulting in hindered oxygen transport to the active reaction sites. The cathode CL and the GDL play a major role in the mass transport loss and hence in the water management of a PEFC. In this work the development of a mesoscopic modeling formalism coupled with realistic microstructural delineation is presented to study the influence of the pore structure and surface wettability on liquid water transport and interfacial dynamics in the PEFC catalyst layer and gas diffusion layer. The two-phase regime transition phenomenon in the capillary dominated transport in the CL and the influence of the mixed wetting characteristics on the flooding dynamics in the GDL are highlighted.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Solid‐state batteries (SSBs), utilizing a lithium metal anode, promise to deliver enhanced energy and power densities compared to conventional lithium‐ion batteries. Penetration of lithium filaments ...through the solid‐state electrolytes (SSEs) during electrodeposition poses major constraints on the safety and rate performance of SSBs. While microstructural attributes, especially grain boundaries (GBs) within the SSEs are considered preferential metal propagation pathways, the underlying mechanisms are not fully understood yet. Here, a comprehensive insight is presented into the mechanistic interactions at the mesoscale including the electrochemical‐mechanical response of the GB‐electrode junction and competing ion transport dynamics in the SSE. Depending on the GB transport characteristics, a highly non‐uniform electrodeposition morphology consisting of either cavities or protrusions at the GB‐electrode interface is identified. Mechanical stability analysis reveals localized strain ramps in the GB regions that can lead to brittle fracture of the SSE. For ionically less conductive GBs compared to the grains, a crack formation and void filling mechanism, triggered by the heterogeneous nature of electrochemical‐mechanical interactions is delineated at the GB‐electrode junction. Concurrently, in situ X‐ray tomography of pristine and failed Li7La3Zr2O12 (LLZO) SSE samples confirm the presence of filamentous lithium penetration and validity of the proposed mesoscale failure mechanisms.
The morphological stability of lithium metal electrodes in solid‐state batteries remains a major challenge. In this work, the electrochemical‐mechanical interactions and competing ion transport dynamics underlying the stability of grain boundary‐electrode junctions is examined. A mechanistic failure pathway including cavity growth and strain hotspot evolution is triggered due to the ionic transport mismatch between the grains and grain boundaries.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
