Glycocalyx Research Articles

A novel, microfluidic high-throughput single-cell encapsulation of human bone marrow mesenchymal stromal cells

The efficacy of stem-cell therapy depends on the ability of the transplanted cells to escape early immunological reactions and to be retained at the site of transplantation. The use of tissue engineering scaffolds or injectable biomaterials as carriers has been proposed, but they still present limitations linked to a reliable manufacturing process, surgical practice and clinical outcomes. Alginate microbeads are potential candidates for the encapsulation of mesenchymal stromal cells with the aim of providing a delivery carrier suitable for minimally-invasive and scaffold-free transplantation, tissue-adhesive properties and protection from the immune response. However, the formation of stable microbeads relies on the cross-linking of alginate with divalent calcium ions at concentrations that are toxic for the cells, making control over the beads’ size and a single-cell encapsulation unreliable. The present work demonstrates the efficiency of an innovative, high throughput, and reproducible microfluidic system to produce single-cell, calcium-free alginate coatings of human mesenchymal stromal cells. Among the various conditions tested, visible light and confocal microscopy following staining of the cell nuclei by DAPI showed that the microfluidic system yielded an optimal single-cell encapsulation of 2000 cells/min in 2% w/v alginate microcapsules of reproducible morphology and an average size of 28.2 ± 3.7 µm. The adhesive properties of the alginate microcapsules, the viability of the encapsulated cells and their ability to escape the alginate microcapsule were demonstrated by the relatively rapid adherence of the beads onto tissue culture plastic and the cells’ ability to gradually disrupt the microcapsule shell after 24 h and proliferate. To mimic the early inflammatory response upon transplantation, the encapsulated cells were exposed to proliferating macrophages at different cell seeding densities for up to 2 days and the protection effect of the microcapsule on the cells assessed by time-lapse microscopy showing a shielding effect for up to 48 h. This work underscores the potential of microfluidic systems to precisely encapsulate cells by good manufacturing practice standards while favouring cell retention on substrates, viability and proliferation upon transplantation.Graphical

SiO2/WO3/ZnO based self-cleaning coatings for solar cells

The accumulation of pollution and any kinds of contamination on the glass cover of the solar cell affects the efficiency of the photovoltaic (PV) systems. The contamination on the glass cover can absorb and reflect a certain part of the sunlight irradiation, which can decrease the intensity of the light coming in through the glass cover. With the study, it was planned to develop self-cleaning coatings for the PV systems. It was aimed to prevent or reduce the contamination-induced efficiency loss of the existing PV systems. In the scope of the project, SiO2/WO3 and SiO2/WO3/ZnO composites were coated from their solutions on the glass substrates using a dip-coating technique. WO3 was selected as a photocatalyst semiconductor. Under the UV light irradiation, WO3 could absorb the photons of the UV light, generating the photoinduced charge carriers. The photoexcited charge carriers provide both the photoinduced hydrophilicity on the surface of the coating and the photocatalytic degradation of the organic contaminants accumulated on the surface of the coating, which allows water droplets to spread and flow on the surface of the cover glass to remove the contaminations. However, the recombination rate of the photoexcited charge carriers on the WO3 film was high. In order to suppress the recombination of the photoinduced charge carriers, WO3 was coupled with SiO2 and ZnO. Both of these semiconductors improved the photocatalytic activity of the WO3 film. Although SiO2 has superior features in terms of the light transmission, it was not very effective under UV light as a photocatalyst alone. The widely preferred photocatalyst ZnO was added into the composite film structure to enhance the photocatalytic activity. The self-cleaning mechanism of the film coatings on a solar cell was investigated through the photocatalytic dye removal efficiency on the as-prepared film samples. There was a slight decrease in the light transparency and the solar cell efficiency because of the WO3 content of the composite film. On the other hand, coupling the SiO2/WO3 film with ZnO enhanced the photocatalytic activity, and it suppressed the reduction effect of the WO3 phase on both the light transparency and the solar cell efficiency. The photocatalytic dye removal efficiency was increased to over 90% after 240 min of UVA light irradiation. In addition, the solar cell coated with the SiO2/WO3/ZnO film provided almost the same solar cell efficiency as the uncoated solar cell. The water contact angle measurement also exhibited the photocatalytic degradation of the model contamination on the glass cover of the solar cell under the UVA light irradiation.Graphical

Axial–Equatorial Halide Ordering in Layered Hybrid Perovskites from Isotropic–Anisotropic 207Pb NMR

AbstractBandgap‐tuneable mixed‐halide 3D perovskites are of interest for multi‐junction solar cells, but suffer from photoinduced spatial halide segregation. Mixed‐halide 2D perovskites are more resistant to halide segregation and are promising coatings for 3D perovskite solar cells. The properties of mixed‐halide compositions depend on the local halide distribution, which is challenging to study at the level of single octahedra. In particular, it has been suggested that there is a preference for occupation of the distinct axial and equatorial halide sites in mixed‐halide 2D perovskites. 207Pb NMR can be used to probe the atomic‐scale structure of lead‐halide materials, but although the isotropic 207Pb shift is sensitive to halide stoichiometry, it cannot distinguish configurational isomers. Here, we use 2D isotropic–anisotropic correlation 207Pb NMR and relativistic DFT calculations to distinguish the [PbX6] configurations in mixed iodide–bromide 3D FAPb(Br1−xIx)3 perovskites and 2D BA2Pb(Br1−xIx)4 perovskites based on formamidinium (FA+) and butylammonium (BA+), respectively. We find that iodide preferentially occupies the axial site in BA‐based 2D perovskites, which may explain the suppressed halide mobility.

Axial-Equatorial Halide Ordering in Layered Hybrid Perovskites from Isotropic-Anisotropic 207 Pb NMR.

Bandgap-tuneable mixed-halide 3D perovskites are of interest for multi-junction solar cells, but suffer from photoinduced spatial halide segregation. Mixed-halide 2D perovskites are more resistant to halide segregation and are promising coatings for 3D perovskite solar cells. The properties of mixed-halide compositions depend on the local halide distribution, which is challenging to study at the level of single octahedra. In particular, it has been suggested that there is a preference for occupation of the distinct axial and equatorial halide sites in mixed-halide 2D perovskites. 207 Pb NMR can be used to probe the atomic-scale structure of lead-halide materials, but although the isotropic 207 Pb shift is sensitive to halide stoichiometry, it cannot distinguish configurational isomers. Here, we use 2D isotropic-anisotropic correlation 207 Pb NMR and relativistic DFT calculations to distinguish the [PbX6 ] configurations in mixed iodide-bromide 3D FAPb(Br1-x Ix )3 perovskites and 2D BA2 Pb(Br1-x Ix )4 perovskites based on formamidinium (FA+ ) and butylammonium (BA+ ), respectively. We find that iodide preferentially occupies the axial site in BA-based 2D perovskites, which may explain the suppressed halide mobility.

Glycocalyx analysis of bladder cancer: three-dimensional images in electron microscopy and vicia villosa lectin as a marker for invasiveness in frozen sections.

Introduction: The abnormal glycocalyx (GCX) on the surface of cancer cells has been reported to be tall and aberrantly glycosylated and has been linked to the progression and spread of cancer-a finding also observed in bladder cancer. However, the characteristics of GCX in various types of human bladder cancer remain unknown, and herein, we aimed to provide information on the diversity of glycan components in the GCX of bladder cancers and to shed light on their characteristics. Methods: We used scanning electron microscopy and lanthanum staining to examine the surface GCX of human bladder carcinomas in three-dimensional images, showing the bulky GCX in some carcinomas. We also examined glycan alterations in early to progressive stages of bladder cancers using 20 distinct lectin stains on frozen sections from transurethral resection of bladder tumors. Results and discussion: Distinctive Vicia villosa lectin (VVL) staining was observed in invasive urothelial carcinomas, including those with muscle invasion and variant components. In the clinical setting, cancers with atypia of grades 2-3 had a significantly higher VVL scoring intensity than those with grade 1 atypia (p < 0.005). This study identified that a specific lectin, VVL, was more specific to invasive urothelial carcinomas. This lectin, which selectively binds to sites of cancer progression, is a promising target for drug delivery in future clinical investigations.

Coating Performance Prediction using a Modified Spin Coater and the Taguchi Technique for Solar Cells

Background:: This paper presents a novel approach to enhance the efficiency of solar cells by employing a modified spin coating technique with a Zinc oxide (ZnO) solution. Spin coating, known for its ability to achieve uniform, thin coatings on flat to moderately curved surfaces, serves as the central method in this research. The study meticulously investigates various factors affecting the coating process, including the volume of the solution, spinning speed, and spinning duration. To optimize these factors effectively, the Taguchi approach is employed, aiming to achieve the desired ZnO layer thickness and uniformity. The experimental findings reveal that the most favorable results are obtained when implementing a 3-second spin cycle at a rapid spin speed of 2000 rpm while using a ZnO solution volume of 5 microliters. Furthermore, advanced techniques such as scanning electron microscopy (SEM) are harnessed to scrutinize the surface characteristics of the ZnO layer and its interaction with the solution. To gauge the quality of the coatings, the signal-tonoise ratio (SNR) main impact plot is thoughtfully utilized. Subsequent in-depth analysis, employing the analysis of variance (ANOVA) technique, delves into the intricate relationship between the experimental parameters and the response parameter. The research outcomes are nothing short of remarkable, showcasing that the modified spin coating technique significantly elevates the efficiency of coated solar cells, ultimately achieving an impressive efficiency rate of 5.4%. In summation, this study introduces a pioneering spin coating technique tailored for solar cell applications with ZnO solution, leading to substantial enhancements in efficiency. The thorough optimization of process parameters through the Taguchi technique, coupled with the comprehensive analysis of experimental results via ANOVA, not only advances the comprehension of the coating process but also paves the way for more efficient and sustainable solar cell applications in the future. Methods:: The research systematically explored critical factors affecting the coating process for solar cells, optimizing the ZnO layer's thickness and uniformity. The ideal parameters identified were a 3-second spin cycle at 2000 rpm with a ZnO solution volume of 5 microliters. Quality assessment was done using the signal-to-noise ratio (SNR) main impact plot, and further analysis via ANOVA revealed intricate parameter relationships. These findings offer a precise and efficient method for improving solar cell coatings, promising enhanced efficiency in renewable energy production. Results:: The research achieved a minimum film thickness of 4.2 micrometers and revealed a correlation between spinning speed and film thickness. Solar cell efficiency reached an impressive 5.4% post-ZnO coating. The modified spin coating device outperformed conventional methods, enhancing efficiency by 5% to 10%. These results signify a significant breakthrough in improving solar cell performance and hold promise for more efficient solar energy production. Conclusion:: This research optimized the spin coating process to apply ZnO solution to solar cells, achieving the desired film thickness. Ideal parameters were found: 2000 rpm spinning speed, three seconds spinning duration, and four microliters of solution. This resulted in a minimum film thickness of 4.2 micrometers. Higher spinning speeds correlated with thinner films, as shown in a contour plot. Solar cell efficiency reached 5.4% after the ZnO coating. A redesigned spin coating device outperformed conventional methods, improving efficiency by 5% to 10%. This modified technique holds promise for more efficient solar panel production.

Dynamics of an aqueous suspension of short hyaluronic acid chains near a DPPC bilayer.

The synergy between hyaluronic acid (HA) and lipid molecules plays a crucial role in synovial fluids, cell coatings, etc. Diseased cells in cancer and arthritis show changes in HA concentration and chain size, impacting the viscoelastic and mechanical properties of the cells. Although the solution behavior of HA is known in experiments, a molecular-level understanding of the role of HA in the dynamics at the interface of HA-water and the cellular boundary is lacking. Here, we perform atomistic molecular dynamics simulation of short HA chains in an explicit water solvent in the presence of a DPPC bilayer, relevant in pathological cases. We identify a stable interface between HA-water and the bilayer where the water molecules are in contact with the bilayer and the HA chains are located away without any direct contact. Both translation and rotation of the interfacial waters in contact with the lipid bilayer and translation of the HA chains exhibit subdiffusive behavior. The diffusive behavior sets in slightly away from the bilayer, where the diffusion coefficients of water and HA decrease monotonically with increase in HA concentration. On the contrary, the dependence on HA chain size is only marginal due to enhanced chain flexibility as their size increases.

Sustainable Fabrication of ZnO Nanostructures for Enhanced Photovoltaic Performance: Insights from SEM and XRD Analysis

The study of sustainable ZnO nanostructure coatings for photovoltaic cells has advanced solar energy technologies. Hydrothermal and sol-gel methods were utilized to make ZnO nanorods, nanowires, nanoflowers, nanoplates, and nanotubes. These nanostructures have many shapes and crystalline arrangements. SEM revealed different shapes. The average length of nanorods, nanoflowers, nanoplates, and nanotubes is 150, 120, 200, and 160 nm, respectively. XRD verified crystal structures and dimensions. The 25–30 nanometer crystals have orientations of (002), (101), (103), (110), and (112). These nanoparticles greatly improved solar cell performance. Open circuit voltages were 0.65 V to 0.74 V, while short circuit currents were 11.3 mA to 13.5 mA. Power conversion efficiency ranged from 5.9% to 7.1%, while fill factors were 76% to 85%. A strong association exists between nanostructure morphology, structural properties, and cellular performance. This shows how these settings improve solar cell efficiency. These findings show that ecologically friendly ZnO nanoparticles have exciting potential. They point to efficient, ecologically friendly solar energy conversion methods. Research and development of customized nanoparticles may improve solar devices. This may provide eco-friendly and efficient solar energy systems.

Study of Effect of Calcinations Temperature on Structural and Magnetic Properties of MgMnO2-λ Nanocrystallines

The researchers are interested in studying nanoparticulates as a result of their specific Physical, Chemical and Biological traits. These nanoparticulates are additionally applicable to a wide array of industries, which includes solar cell coatings, transparent sunscreen, self-cleaning windows and scratch-resistant eyewear. Nanoparticulates have significant properties at nano scale because of high surface to volume ratio. The advanced properties of these nanoparticulates increase the interest of today’s researchers and scientist. The metal oxide nanoparticulates of MgO have enhanced properties in the field of industries, defense and medical world. Metal oxide nanoparticulates like MgO and MnO2 are currently the subject of substantial research because of their well-known antibacterial activity against several kinds of bacteria and their advanced uses in the field of storage for hydrogen gas. In the current work, pure MgO and Mn (10%) doped MgO nanoparticulates were prepared via a microwave irradiated chemical co precipitation process . The samples were further calcined at 200o , 400o , 600o and 800o Celsius for two hours constant heating. XRD, FTIR, FESEM, and VSM examinations have been conducted on the calcined materials. The XRD results revels that nanoparticulates were formed with FCC crystal structures and no phase transformation occurred with addition of Mn dopant concentration in MgO. However, the presence of Mn2+ ion in place of Mg2+ ion were recognized via broadening of peak resulted by micro strain lattice. The grain size of nanoparticulates were calculated by use of Debye Scherer estimation and crystalline size 29.47nm, 27.68nm, 36.80nm and 46.14 nm pattern shows that crystallite size increases with increase in calcinations temperature. The IR sharp peaks inspected at 409cm-1 (pure MgO/800OC), 395cm-1 (pure MgO/600oC), 402cm-1 (pure MgO/400oC) and 409cm-1 (pure MgO/200oC) respectively and for Mn doped MgO nanoparticulates sharp peaks inspected at 450 cm-1 (Mn10%/600OC),400cm1 (Mn20%/600oC) respectively and were attributed by O-Mn-O molecule vibration were confirmed the XRD analyses that is Mn2+ ion exist at Mg2+ lattice site. The electron microscopic image of sample shows that cauliflower leaf like structure was seen with size nanometer in scale. The VSM characteristic of sample concluded that saturation magnetization gradually decreases with increase of calcinations temperature and all substances were ferromagnetic in behavior. The materials have recommended property in applications as electromagnet formation.

Tunable Visible Light and Energy Transfer Mechanism in Tm3+ and Silver Nanoclusters within Co-Doped GeO2-PbO Glasses.

This study introduces a novel method for producing Ag nanoclusters (NCs) within GeO2-PbO glasses doped with Tm3+ ions. Sample preparation involved the melt-quenching method, employing adequate heat treatment to facilitate Ag NC formation. Absorption spectroscopy confirmed trivalent rare-earth ion incorporation. Ag NC identification and the amorphous structure were observed using transmission electron microscopy. A tunable visible emission from blue to the yellow region was observed. The energy transfer mechanism from Ag NCs to Tm3+ ions was demonstrated by enhanced 800 nm emission under 380 and 400 nm excitations, mainly for samples with a higher concentration of Ag NCs; moreover, the long lifetime decrease of Ag NCs at 600 nm (excited at 380 and 400 nm) and the lifetime increase of Tm3+ ions at 800 nm (excitation of 405 nm) corroborated the energy transfer between those species. Therefore, we attribute this energy transfer mechanism to the decay processes from S1→T1 and T1→S0 levels of Ag NCs to the 3H4 level of Tm3+ ions serving as the primary path of energy transfer in this system. GeO2-PbO glasses demonstrated potential as materials to host Ag NCs with applications for photonics as solar cell coatings, wideband light sources, and continuous-wave tunable lasers in the visible spectrum, among others.

Endothelial glycocalyx sensitivity to chemical and mechanical sub-endothelial substrate properties.

Glycocalyx (GCX) is a carbohydrate-rich structure that coats the surface of endothelial cells (ECs) and lines the blood vessel lumen. Mechanical perturbations in the vascular environment, such as blood vessel stiffness, can be transduced and sent to ECs through mechanosensors such as GCX. Adverse stiffness alters GCX-mediated mechanotransduction and leads to EC dysfunction and eventually atherosclerotic cardiovascular diseases. To understand GCX-regulated mechanotransduction events, an in vitro model emulating in vivo vessel conditions is needed. To this end, we investigated the impact of matrix chemical and mechanical properties on GCX expression via fabricating a tunable non-swelling matrix based on the collagen-derived polypeptide, gelatin. To study the effect of matrix composition, we conducted a comparative analysis of GCX expression using different concentrations (60-25,000μg/mL) of gelatin and gelatin methacrylate (GelMA) in comparison to fibronectin (60μg/mL), a standard coating material for GCX-related studies. Using immunocytochemistry analysis, we showed for the first time that different substrate compositions and concentrations altered the overall GCX expression on human umbilical vein ECs (HUVECs). Subsequently, GelMA hydrogels were fabricated with stiffnesses of 2.5 and 5kPa, representing healthy vessel tissues, and 10kPa, corresponding to diseased vessel tissues. Immunocytochemistry analysis showed that on hydrogels with different levels of stiffness, the GCX expression in HUVECs remained unchanged, while its major polysaccharide components exhibited dysregulation in distinct patterns. For example, there was a significant decrease in heparan sulfate expression on pathological substrates (10kPa), while sialic acid expression increased with increased matrix stiffness. This study suggests the specific mechanisms through which GCX may influence ECs in modulating barrier function, immune cell adhesion, and mechanotransduction function under distinct chemical and mechanical conditions of both healthy and diseased substrates.

Biomaterial-Mediated Exogenous Facile Coating of Natural Killer Cells for Enhancing Anticancer Efficacy toward Hepatocellular Carcinoma.

Natural killer (NK) cells exhibit a good therapeutic efficacy against various malignant cancer cells. However, the therapeutic efficacy of plain NK cells is relatively low due to inadequate selectivity for cancer cells. Therefore, to enhance the targeting selectivity and anticancer efficacy of NK cells, we have rationally designed a biomaterial-mediated ex vivo surface engineering technique for the membrane decoration of cancer recognition ligands onto NK cells. Our designed lipid conjugate biomaterial contains three major functional moieties: (1) 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) lipid for cell membrane anchoring, (2) polyethylene glycol for intracellular penetration blocker, and (3) lactobionic acid (LBA) for cancer recognition. The biomaterial was successfully applied to NK cell surfaces (LBA-NK) to enhance recognition and anticancer functionalities, especially toward asialoglycoprotein receptor (ASGPR)-overexpressing hepatocellular carcinoma. Highly efficient and homogeneous NK cell surface editing was achieved with a simple coating process while maintaining intrinsic properties of NK cells. LBA-NK cells showed potential ASGPR-mediated tumor cell binding (through LBA-ASGPR interaction) and thereby significantly augmented anticancer efficacies against HepG2 liver cancer cells. Thus, LBA-NK cells can be a novel engineering strategy for the treatment of liver cancers via facilitated immune synapse interactions in comparison with currently available cell therapies.

Glycan-modified cellular nanosponges for enhanced neutralization of botulinum toxin

Botulinum toxin (BoNT) is a potent neurotoxin that poses a significant threat as a biowarfare weapon and a potential bioterrorist tool. Currently, there is a lack of effective countermeasures to combat BoNT intoxication in the event of a biological attack. Here, we report on a novel solution by combining cell metabolic engineering with cell membrane coating nanotechnology, resulting in the development of glycan-modified cellular nanosponges that serve as a biomimetic and broad-spectrum BoNT detoxification strategy. Specifically, we increase the expression levels of gangliosides on THP-1 cells through metabolic engineering, and then collect the modified THP-1 cell membrane and coat it onto synthetic polymeric cores, creating cellular nanosponges that closely mimic host cells. Our findings demonstrate that higher levels of gangliosides on the cellular nanosponges result in greater binding capacities with BoNT. The glycan-modified cellular nanosponges exhibit superior efficacy in neutralizing BoNT cytotoxicity in vitro when compared to their unmodified counterparts. In a mouse model of BoNT intoxication, the glycan-modified cellular nanosponges show more pronounced survival benefits when administered both as a treatment and a preventative regimen. These results highlight the potential of cellular nanosponges, especially when modified with glycans, as a promising countermeasure platform against BoNT and related clostridial toxins.

Design of core-shell SiO2 nanoparticles to create anti-reflection and anti-fouling coatings for solar cells

Amphiphobic coatings with the anti-reflective property offer a promising strategy to mitigate the degradation of photovoltaic conversion efficiency in solar cells caused by fouling and reflection of incident light. Despite advancements in developing transparent and liquid-repellent coatings, achieving integration of both properties still poses a significant challenge. In this work, a unique nanostructure coating with extremely low roughness and surface energy is constructed by integrating fluorinated cluster core-shell structured silicon sols (BASSF) into a self-made silicon precursor (SP) using a template-free two-step base/acid-catalyzed reaction. The exceptional anti-fouling performance of the S-P@BASSF coating is a result of the chemical inertness of the polymer and the unique structure of the sol-gel particles. This innovative approach provides a potential solution for fabricating high-performance coatings and materials. The coating is capable of recovering to 97 % of its initial efficiency swiftly, even after severe dust contamination. The coating exhibits remarkable anti-reflective property due to the combination of sol particles with varying refractive indices. The coating also displays high weathering resistance, maintaining contact angles with water (≥105°) and diiodomethane (≥85°) even after prolonged exposure to UV lamps, high temperature and high humidity weather. The results obtained in this study show that nanocomposite coatings via the preparation of smooth, high refractive index and low reflectivity have great potential for outdoor applications such as energy harvesting and optical instruments under wet conditions.

Air-Knife-Assisted Spray Coating of Organic Solar Cells.

The power conversion efficiencies (PCEs) of organic solar cells (OSCs) have risen dramatically since the introduction of the "Y-series" of non-fullerene acceptors. However, the demonstration of rapid scalable deposition techniques to deposit such systems is rare. Here, for the first time, we demonstrate the deposition of a Y-series-based system using ultrasonic spray coating─a technique with the potential for significantly faster deposition speeds than most traditional meniscus-based methods. Through the use of an air-knife to rapidly remove the casting solvent, we can overcome film reticulation, allowing the drying dynamics to be controlled without the use of solvent additives, heating the substrate, or heating the casting solution. The air-knife also facilitates the use of a non-halogenated, low-toxicity solvent, resulting in industrially relevant, spray-coated PM6:DTY6 devices with PCEs of up to 14.1%. We also highlight the obstacles for scalable coating of Y-series-based solar cells, in particular the influence of slower drying times on blend morphology and crystallinity. This work demonstrates the compatibility of ultrasonic spray coating, and use of an air-knife, with high-speed, roll-to-roll OSC manufacturing techniques.

Fast-track preparation of lung specimens for electron microscope observations of the pulmonary endothelial glycocalyx.

The glycocalyx (GCX) covers the luminal surface of blood vessels and regulates vascular permeability. As GCX degradation predicts various types of vasculopathy, confirming the presence of this structure is useful for diagnosis. Since the GCX layer is very fragile, careful fixation is necessary to preserve its structure. We explored appropriate and feasible methodologies for visualizing the GCX layer using lung tissue specimens excised from anesthetized mice. Each specimen was degassed and immersed in Alcian blue (ALB) fixative solution, and then observed using electron microscopy. Specimens from septic mice were prepared as negative GCX controls. Using these immersion-fixed specimens, the GCX layer was successfully observed using both transmission and scanning electron microscopy; these observations were similar to those obtained using the conventional method of lanthanum perfusion fixation. Spherical aggregates of GCX were observed in the septic mouse specimens, and the GCX density was lower in the septic specimens than in the non-septic specimens. Of note, the presently reported methodology reduced the specimen preparation time from 6 to 2days. We, therefore, concluded that our novel method could be applied to human lung specimens and could potentially contribute to the further elucidation of vasculopathies.

A Microbial Cell Coating Based on a Conjugated Polyelectrolyte with Broad Reduction Potential Increases Inward and Outward Extracellular Electron Transfer (Adv. Electron. Mater. 7/2023)

A Microbial Cell Coating Based on a Conjugated Polyelectrolyte with Broad Reduction Potential Increases Inward and Outward Extracellular Electron Transfer (Adv. Electron. Mater. 7/2023)

Cardiac Pericytes Acquire a Fibrogenic Phenotype and Contribute to Vascular Maturation After Myocardial Infarction.

Pericytes have been implicated in tissue repair, remodeling, and fibrosis. Although the mammalian heart contains abundant pericytes, their fate and involvement in myocardial disease remains unknown. We used NG2Dsred;PDGFRαEGFP pericyte:fibroblast dual reporter mice and inducible NG2CreER mice to study the fate and phenotypic modulation of pericytes in myocardial infarction. The transcriptomic profile of pericyte-derived cells was studied using polymerase chain reaction arrays and single-cell RNA sequencing. The role of transforming growth factor-β (TGF-β) signaling in regulation of pericyte phenotype was investigated in vivo using pericyte-specific TGF-β receptor 2 knockout mice and in vitro using cultured human placental pericytes. In normal hearts, neuron/glial antigen 2 (NG2) and platelet-derived growth factor receptor α (PDGFRα) identified distinct nonoverlapping populations of pericytes and fibroblasts, respectively. After infarction, a population of cells expressing both pericyte and fibroblast markers emerged. Lineage tracing demonstrated that in the infarcted region, a subpopulation of pericytes exhibited transient expression of fibroblast markers. Pericyte-derived cells accounted for ~4% of PDGFRα+ infarct fibroblasts during the proliferative phase of repair. Pericyte-derived fibroblasts were overactive, expressing higher levels of extracellular matrix genes, integrins, matricellular proteins, and growth factors, when compared with fibroblasts from other cellular sources. Another subset of pericytes contributed to infarct angiogenesis by forming a mural cell coat, stabilizing infarct neovessels. Single-cell RNA sequencing showed that NG2 lineage cells diversify after infarction and exhibit increased expression of matrix genes, and a cluster with high expression of fibroblast identity markers emerges. Trajectory analysis suggested that diversification of infarct pericytes may be driven by proliferating cells. In vitro and in vivo studies identified TGF-β as a potentially causative mediator in fibrogenic activation of infarct pericytes. However, pericyte-specific TGF-β receptor 2 disruption had no significant effects on infarct myofibroblast infiltration and collagen deposition. Pericyte-specific TGF-β signaling was involved in vascular maturation, mediating formation of a mural cell coat investing infarct neovessels and protecting from dilative remodeling. In the healing infarct, cardiac pericytes upregulate expression of fibrosis-associated genes, exhibiting matrix-synthetic and matrix-remodeling profiles. A fraction of infarct pericytes exhibits expression of fibroblast identity markers. Pericyte-specific TGF-β signaling plays a central role in maturation of the infarct vasculature and protects from adverse dilative remodeling, but it does not modulate fibrotic remodeling.

Heme Interactions as Regulators of the Alternative Pathway Complement Responses and Implications for Heme-Associated Pathologies.

Heme (Fe2+-protoporphyrin IX) is a pigment of life, and as a prosthetic group in several hemoproteins, it contributes to diverse critical cellular processes. While its intracellular levels are tightly regulated by networks of heme-binding proteins (HeBPs), labile heme can be hazardous through oxidative processes. In blood plasma, heme is scavenged by hemopexin (HPX), albumin and several other proteins, while it also interacts directly with complement components C1q, C3 and factor I. These direct interactions block the classical pathway (CP) and distort the alternative pathway (AP). Errors or flaws in heme metabolism, causing uncontrolled intracellular oxidative stress, can lead to several severe hematological disorders. Direct interactions of extracellular heme with alternative pathway complement components (APCCs) may be implicated molecularly in diverse conditions at sites of abnormal cell damage and vascular injury. In such disorders, a deregulated AP could be associated with the heme-mediated disruption of the physiological heparan sulphate-CFH coat of stressed cells and the induction of local hemostatic responses. Within this conceptual frame, a computational evaluation of HBMs (heme-binding motifs) aimed to determine how heme interacts with APCCs and whether these interactions are affected by genetic variation within putative HBMs. Combined computational analysis and database mining identified putative HBMs in all of the 16 APCCs examined, with 10 exhibiting disease-associated genetic (SNPs) and/or epigenetic variation (PTMs). Overall, this article indicates that among the pleiotropic roles of heme reviewed, the interactions of heme with APCCs could induce differential AP-mediated hemostasis-driven pathologies in certain individuals.

Fluorescent Waveguide Lattices for Enhanced Light Harvesting and Solar Cell Performance.

We present the properties and performance of fluorescent waveguide lattices as coatings for solar cells, designed to address the significant mismatch between the solar cell's spectral response range and the solar spectrum. Using arrays of microscale visible light optical beams transmitted through photoreactive polymer resins comprising acrylate and silicone monomers and fluorescein o,o'-dimethacrylate comonomer, we photopolymerize well-structured films with single and multiple waveguide lattices. The materials exhibited bright green-yellow fluorescence emission through down-conversion of blue-UV excitation and light redirection from the dye emission and waveguide lattice structure. This enables the films to collect a broader spectrum of light, spanning UV-vis-NIR over an exceptionally wide angular range of ±70°. When employed as encapsulant coatings on commercial silicon solar cells, the polymer waveguide lattices exhibited significant enhancements in solar cell current density. Below 400 nm, the primary mode of enhancement is through down-conversion and light redirection from the dye emission and collection by the waveguides. Above 400 nm, the primary modes of enhancement were a combination of down-conversion, wide-angle light collection, and light redirection from the dye emission and collection by the waveguides. Waveguide lattices with higher dye concentrations produced more well-defined structures better suited for current generation in encapsulated solar cells. Under standard AM 1.5 G irradiation, we observed nominal average current density increases of 0.7 and 1.87 mA/cm2 for single waveguide lattices and two intersecting lattices, respectively, across the full ±70° range and reveal optimal dye concentrations and suitable lattice structures for solar cell performance. Our findings demonstrate the significant potential of incorporating down-converting fluorescent dyes in polymer waveguide lattices for improving the current spectral and angular response of solar cell technologies toward increasing clean energy in the energy grid.