Despite intensive research efforts, reports of cellular responses to nanomaterials are often inconsistent and even contradictory. Additionally, relationships between the responding cell type and ...nanomaterial properties are not well understood. Using three model cell lines representing different physiological compartments and nanomaterials of different compositions and sizes, we have systematically investigated the influence of nanomaterial properties on the degrees and pathways of cytotoxicity. In this study, we selected nanomaterials of different compositions (TiO2 and SiO2 nanoparticles, and multi-wall carbon nanotubes MWCNTs) with differing size (MWCNTs of different diameters < 8 nm, 20-30 nm, > 50 nm; but same length 0.5-2 microm) to analyze the effects of composition and size on toxicity to 3T3 fibroblasts, RAW 264.7 macrophages, and telomerase-immortalized (hT) bronchiolar epithelial cells.
Following characterization of nanomaterial properties in PBS and serum containing solutions, cells were exposed to nanomaterials of differing compositions and sizes, with cytotoxicity monitored through reduction in mitochondrial activity. In addition to cytotoxicity, the cellular response to nanomaterials was characterized by quantifying generation of reactive oxygen species, lysosomal membrane destabilization and mitochondrial permeability. The effect of these responses on cellular fate - apoptosis or necrosis - was then analyzed. Nanomaterial toxicity was variable based on exposed cell type and dependent on nanomaterial composition and size. In addition, nanomaterial exposure led to cell type dependent intracellular responses resulting in unique breakdown of cellular functions for each nanomaterial: cell combination.
Nanomaterials induce cell specific responses resulting in variable toxicity and subsequent cell fate based on the type of exposed cell. Our results indicate that the composition and size of nanomaterials as well as the target cell type are critical determinants of intracellular responses, degree of cytotoxicity and potential mechanisms of toxicity.
There is growing evidence to suggest that employees' perceptions of their employer's corporate social responsibility (CSR) positively influences their attitude and behavior. An increasing number of ...scholars have called for further explorations of the microfoundations of CSR. To that end, this study takes the conservation of resources perspective to examine relationships and the perception of CSR by employees, considering areas such as thriving at work, task significance, and employees taking charge. By analyzing 444 questionnaires completed by employees in China and using the conditional process analysis to test a hypothesis, results showed that the association between employees' CSR perception and taking charge is significantly and positively correlated, with thriving at work mediating the connection. We also found that task significance negatively moderates the mediating effect between CSR and taking charge, such that the lower the level of task significance of a job, the more positive the effect of CSR on taking charge via thriving at work. These findings have theoretical implications for micro-level CSR research and managerial implications for entrepreneurs.
Metallic materials have been extensively applied in clinical practice due to their unique mechanical properties and durability. Recent years have witnessed broad interests and advances on surface ...functionalization of metallic implants for high-performance biofunctions. Calcium phosphates (CaPs) are the major inorganic component of bone tissues, and thus owning inherent biocompatibility and osseointegration properties. As such, they have been widely used in clinical orthopedics and dentistry. The new emergence of surface functionalization on metallic implants with CaP coatings shows promise for a combination of mechanical properties from metals and various biofunctions from CaPs. This review provides a brief summary of state-of-art of surface biofunctionalization on implantable metals by CaP coatings. We first glance over different types of CaPs with their coating methods and in vitro and in vivo performances, and then give insight into the representative biofunctions, i.e. osteointegration, corrosion resistance and biodegradation control, and antibacterial property, provided by CaP coatings for metallic implant materials.
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•Discussions on the various biofunctions of CaP coatings.•Summary of different types of CaPs and their recent development.•Summary of CaP coating methods and selection criteria.
The objective of this research is to develop a dual growth factor-releasing nanoparticle-in-nanofiber system for wound healing applications. In order to mimic and promote the natural healing ...procedure, chitosan and poly(ethylene oxide) were electrospun into nanofibrous meshes as mimics of extracellular matrix. Vascular endothelial growth factor (VEGF) was loaded within nanofibers to promote angiogenesis in the short term. In addition, platelet-derived growth factor-BB (PDGF-BB) encapsulated poly(lactic-co-glycolic acid) nanoparticles were embedded inside nanofibers to generate a sustained release of PDGF-BB for accelerated tissue regeneration and remodeling. In vitro studies revealed that our nanofibrous composites delivered VEGF quickly and PDGF-BB in a relayed manner, supported fibroblast growth and exhibited anti-bacterial activities. A preliminary in vivo study performed on normal full thickness rat skin wound models demonstrated that nanofiber/nanoparticle scaffolds significantly accelerated the wound healing process by promoting angiogenesis, increasing re-epithelialization and controlling granulation tissue formation. For later stages of healing, evidence also showed quicker collagen deposition and earlier remodeling of the injured site to achieve a faster full regeneration of skin compared to the commercial Hydrofera Blue® wound dressing. These results suggest that our nanoparticle-in-nanofiber system could provide a promising treatment for normal and chronic wound healing.
Zn
is an essential element for cell survival/growth, and its deficiency is linked to many disorders. Extracellular Zn
concentration changes participate in modulating fundamental cellular processes ...such as proliferation, secretion, ion transport, and cell signal transduction in a mechanism that is not well understood. Here, we hypothesize that the Zn
-sensing receptor ZnR/G protein-coupled receptor 39 (GPR39), found in tissues where dynamic Zn
homeostasis takes place, enables extracellular Zn
to trigger intracellular signaling pathways regulating key cell functions in vascular cells. Thus, we investigated how extracellular Zn
regulates cell viability, proliferation, motility, angiogenesis, vascular tone, and inflammation through ZnR/GPR39 in endothelial cells. Knockdown of GPR39 through siRNA largely abolished Zn
-triggered cellular activity changes, Ca
responses, as well as the downstream activation of Gαq-PLC pathways. Extracellular Zn
promoted vascular cell survival/growth through activation of cAMP and Akt as well as overexpressing of platelet-derived growth factor-α receptor and vascular endothelial growth factor A. It also enhanced cell adhesion and mobility, endothelial tubule formation, and cytoskeletal reorganization. Such effects from extracellular Zn
were not observed in GPR39
endothelial cells. Zn
also regulated inflammation-related key molecules such as heme oxygenase-1, selectin L, IL-10, and platelet endothelial cell adhesion molecule 1, as well as vascular tone-related prostaglandin I2 synthase and nitric oxide synthase-3. In sum, extracellular Zn
regulates endothelial cell activity in a ZnR/GPR39-dependent manner and through the downstream G
q-PLC pathways. Thus, ZnR/GPR39 may be a therapeutic target for regulating endothelial activity.
Threatened miscarriages is a common complication of first-trimester pregnancy. Due to the beneficial effects, there are increasing clinical studies on Yunkang oral liquid(YKOL). However, the efficacy ...and safety of YKOL are still unknown. The aim of this systematic review was to assess the efficacy and safety of YKOL in the treatment of threatened miscarriage during the first-trimester pregnancy (TMFP).
This protocol will be prepared according to the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) statement. The systematic review will include all randomized controlled trials (RCTs) studies published until April 2021. Electronic sources including CNKI, WF, VIP, CBM, MEDLINE(PubMed), Embase, Cochrane Library, and Web of Science will be searched for potentially eligible studies. The international clinical trial registration platform and the Chinese clinical trial registration platform of controlled trials will be searched from their inception until April 1st, 2021. According to the inclusion and exclusion criteria, screening literature, extraction data will be conducted by two researchers independently. Statistical analysis will use RevMan 5.3.5 software. The strength of evidence from the studies will be evaluated with the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) methods.
This study will provide evidence for YKOL combined with conventional therapy for TMFP.
The efficacy and safety of YKOL combined with conventional therapy for TMFP will be assessed.
INPLASY202140105 (https://www.doi.org/10.37766/inplasy2021.4.0105).
Studies have shown that wound pH is a potentially influential factor in the healing process. Due to the flaws of traditional pH measurement approaches, wound pH measurement has not become part of ...current standard of care. A near‐infrared pH‐sensitive ratiometric film was created and characterized for measuring wound pH. This film was fabricated by physically absorbing poly (N‐isopropyl Acrylamide) nanoparticles conjugated with pH‐sensitive (CypHer5E) and pH‐insensitive (Cy7) fluorescent dyes into 2‐hydroxyethyl methacrylate hydrogel film. The pH pattern on wounds can be indirectly measured by pressing freshly discarded wound dressing on top of the pH‐sensitive film and imaging it. In vitro tests show that the film can accurately and rapidly detect a wide range of pH (from pH 4 to 8) in wound milieu. Further, patient studies showed that, by measuring pH on wound contact side of discarded wound gauze, the pH and its non‐homogeneous distribution on wounds can be indirectly determined. By comparing patients with different wound conditions, we find that near‐infrared pH sensing film can be used to measure wound exudate pH with high accuracy and efficiency. In addition, wound pH determination can provide an accurate assessment of wound healing activity in real time.
High-efficiency quantum dots light-emitting diodes have been showing promise in the development of optoelectronic devices in displays and solid-state lighting. However, quantum dots surface traps ...strongly quench its luminescence when transfer it from in solution into on film. We propose a reproducible method of studying photoluminescence decay dynamics in nanocrystals by implementing surface passivation engineering, the results reveal that quantum dots surface traps-being the main cause of the fluorescence quenching and non-radiative recombination-could be eliminated by a series of surface post-treatment processes. Moreover, we study the quantum dots transient fluorescence spectra that the PL decay channel turned from the double exponential decay (control) to the mono-exponential decay kinetics (both the green and red quantum dots with UV-water co-treatment), and their quantum yields and stability are improved. Here we report all solution-processed multilayer monochromatic quantum dots light-emitting diodes what the emitting layer is formed from the surface post-treated red/green/blue quantum dots. These devices have exhibited a maximum current efficiency and external quantum efficiencies (EQE) of 20.7 cd/A and 14.4% for red, 65.1 cd/A and 15.9% for green, and 4.8 cd/A and 14.7% for blue devices, respectively. We expect the successful quantum dots surface passivation engineering would exert profound influence on their applications to light emitting devices.
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•Quantum dots surface passivation engineering improved their quantum yields.•By the synergistic effect, quantum dots transient PL decay dynamics turned from double to mono-exponential decay.•After quantum dots post-treatment, the R/G/B QD-LEDs of EQE reached up to 14.4%, 15.9% and 14.7%, respectively.
Animal models have been highly informative for understanding the characteristics, onset, and progression of cystic fibrosis (CF) lung disease. In particular, the CFTR
rat has revealed insights into ...the airway mucus defect characteristic of CF but does not replicate a human-relevant CFTR (cystic fibrosis transmembrane conductance regulator) variant.
We hypothesized that a rat expressing a humanized version of CFTR and harboring the ivacaftor-sensitive variant G551D could be used to test the impact of CFTR modulators on pathophysiologic development and correction.
In this study, we describe a humanized-CFTR rat expressing the G551D variant obtained by zinc finger nuclease editing of a human complementary DNA superexon, spanning exon 2-27, with a 5' insertion site into the rat gene just beyond intron 1. This targeted insertion takes advantage of the endogenous rat promoter, resulting in appropriate expression compared with wild-type animals.
The bioelectric phenotype of the epithelia recapitulates the expected absence of CFTR activity, which was restored with ivacaftor. Large airway defects, including depleted airway surface liquid and periciliary layers, delayed mucus transport rates, and increased mucus viscosity, were normalized after the administration of ivacaftor.
This model is useful to understand the mechanisms of disease and the extent of pathology reversal with CFTR modulators.
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