Realizing a homogeneous distribution of two-dimensional nanosheets in polymer matrix, avoiding their agglomeration, has been a key scientific challenge in fabricating high-performance polymer ...nanocomposites. Herein, we report a simple and eco-friendly strategy for preparing thermoplastic polyurethane (TPU) nanocomposites with homogeneously dispersed Ti3C2 MXene nanosheets. In this method, MXene is first pretreated with polyethylene glycol (PEG) and then subjected to melt blending with TPU. These processes effectively exfoliate MXene nanosheets, which are then well dispersed inside the TPU matrix. The MXene/TPU nanocomposites show mechanical and thermal properties that are superior to those of pristine TPU. Tensile strength and storage modulus increase by 47.1% and 39.8% at MXene loading values of 0.5 wt%. The onset degradation temperature of the nanocomposites increases by 13.1 °C, whereas the maximum degradation temperature increases by 20.3 °C at 0.5 wt% MXene loading. This study may provide a promising strategy for manufacturing MXene-based polymer nanocomposites with effective reinforced properties at the industrial level.
Until now, poly(3,4-ethylenedioxythiophene):poly(styrensulfonate) (PEDOT:PSS) is widely used in Sn-Pb perovskite solar cells (PSCs) due to its many advantages, including high optical transparency, ...suitable conductivity, superior wettability, and so on. However, the acidic and hydroscopic properties of the PSS component, as well as the incongruous energy level of the hole transport layer (HTL), may lead to unsatisfying interface properties and decreased device performance. Herein, by adding polyethylene glycol dimethacrylate (PEGDMA) into PEDOT:PSS, a newly crosslinked-double-network obtain of PEDOT:PSS@PEGDMA film, which could not only optimize nucleation and crystallinity of Sn-Pb perovskite films, but also suppress defect density and optimize energy level alignment at the HTL/perovskite interface. As a result, the achieves highly efficient and stable mixed Sn-Pb PSCs with an encouraging power conversion efficiency of 20.9%. Additionally, the device can maintain good stability under N
atmosphere.
Fabrication of single and bundled filament-like tissues using hyaluronic acid-based hollow hydrogel fibers.
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Hydrogel fibers with biodegradable and biocompatible features are useful ...for the fabrication of filament-like tissues. We developed cell-laden hyaluronic acid (HA)-based hollow hydrogel fibers to create single and bundled filament-like tissues. The cell-laden fibers were fabricated by crosslinking phenolic-substituted hyaluronic acid (HA-Ph) in an aqueous solution containing cells through a horseradish peroxidase (HRP)-catalyzed reaction in the presence of catalase by extruding the solution in ambient flow of an aqueous solution containing H2O2. The encapsulated cells proliferated and grew within the hollow core, and the cells formed filament-like constructs in both single and bundled fibers, which were obtained by collection on a rotating cylindrical tube. Single and bundled filament-like tissues covered with an additional heterogeneous cell layer were obtained by degrading the fiber membrane using hyaluronidase after covering the fiber surface with heterogeneous cells. Cellular viability was preserved during HA-Ph hydrogel fiber fabrication and filament-like tissue formation. These results demonstrate the feasibility of HA-based hollow hydrogel fibers obtained through HRP- and catalase-mediated reactions to engineer filament-like tissues.
Hydrogels possess high water content and closely mimic the microenvironment of extracellular matrix. In this study, we created a hybrid hydrogel containing type II collagen, hyaluronic acid (HA), and ...polyethylene glycol (PEG) and incorporated magnetic nanoparticles into the hybrid hydrogels of type II collagen-HA-PEG to produce a magnetic nanocomposite hydrogel (MagGel) for cartilage tissue engineering. The results showed that both the MagGel and hybrid gel (Gel) were successfully cross-linked and the MagGel responded to an external magnet while maintaining structural integrity. That is, the MagGel could travel to the tissue defect sites in physiological fluids under remote magnetic guidance. The adhesion density of bone marrow derived mesenchymal stem cells (BMSCs) on the MagGel group in vitro was similar to the control group and greater than the Gel group. The morphology of BMSCs was normal and consistent in all groups. We also found that BMSCs engulfed magnetic nanoparticles in culture and the presence of magnetic nanoparticles did not affect BMSC adhesion and morphology. We hypothesized that the ingested nanoparticles may be eventually broken down by lysosome and excreted through exocytosis; further studies are necessary to confirm this. This study reports a promising magnetic responsive nanocomposite hydrogel for potential cartilage tissue engineering applications, which should be further studied for its effects on cell functions when combined with electromagnetic stimulation.
The short lifetime of protein-based therapies has largely limited their therapeutic efficacy in injured nervous post-spinal cord injury (post-SCI).
In this study, an affinity-based hydrogel delivery ...system provided sustained-release of proteins, thereby extending the efficacy of such therapies. The affinity-based hydrogel was constructed using a novel polymer, heparin-poloxamer (HP), as a temperature-sensitive bulk matrix and decellular spinal cord extracellular matrix (dscECM) as an affinity depot of drug. By tuning the concentration of HP in formulation, the cold ternary fibroblast growth factor-2 (FGF2)-dscECM-HP solution could rapidly gelatinize into a hydrogel at body temperature. Due to the strong affinity for FGF2, hybrid FGF2-dscECM-HP hydrogel enabled sustained-release of encapsulated FGF2 over an extended period in vitro.
Compared to free FGF2, it was observed that both neuron functions and tissue morphology after SCI were clearly recovered in rats treated with FGF2-dscECM-HP hydrogel. Moreover, the expression of neurofilament protein and the density of axons were increased after treatment with hybrid FGF2-dscECM-HP. In addition, the neuroprotective effects of FGF2-dscECM-HP were related to inhibition of chronic endoplasmic reticulum stress-induced apoptosis.
The results revealed that a hybrid hydrogel system may be a potential carrier to deliver macromolecular proteins to the injured site and enhance the therapeutic effects of proteins.
Lemongrass oil (LGO) is a volatile oil extracted from the leaves of Cymbopogon citratus that has become one of the most important natural oils in the pharmaceutical industry because of its diverse ...pharmacologic and clinical effects. However, LGO suffers from low aqueous solubility, which could lead to a reduced effect. Moreover, the instability of its major active constituent, citral, could lead to volatilization, reaction with other formulation ingredients, and consequently, skin irritation. To surmount these problems, this research aims to formulate lemongrass-loaded ethyl cellulose nanosponges with a topical hydrogel with an enhanced antifungal effect and decreased irritation. The minimal inhibitory concentration and minimal fungicidal concentration of LGO against Candida albicans strain ATC 100231, determined using the broth macrodilution method, were found to be 2 and 8 μL/mL, respectively. The emulsion solvent evaporation technique was used for the preparation of the nanosponges. The nanosponge dispersions were then integrated into carbopol hydrogels (0.4%). Nine formulations were prepared based on a 32 full factorial design employing the ethyl cellulose:polyvinyl alcohol ratio and stirring rate as independent variables. The prepared formulations were evaluated for particle size, citral content, and in vitro release. Results revealed that all the nanosponge dispersions were nanosized, with satisfactory citral content and sustained release profiles. Statistical analysis revealed that both ethyl cellulose:polyvinyl alcohol ratio and stirring rate have significant effects on particle size and percentage released after 6 hours; however, the effect of the stirring rate was more prominent on both responses. The selected hydrogel formulation, F9, was subjected to surface morphological investigations, using scanning and transmission electron microscopy, where results showed that the nanosponges possess a spherical uniform shape with a spongy structure, the integrity of which was not affected by integration into the hydrogel. Furthermore, the selected formulation, F9, was tested for skin irritation and antifungal activity against C. albicans, where results confirmed the nonirritancy and the effective antifungal activity of the prepared hydrogel.
Due to the unique physical and chemical characteristics of hydrogels, such as hydrophilicity, swellability, and modifiability, there is increasing research interest in the development and application ...of novel hydrogels in water and wastewater treatment. Hydrogels have exhibited superior performance in the adsorptive removal of a wide range of aqueous pollutants including heavy metals, nutrients, and toxic dyes. However, there remain certain challenges which need to be addressed in order to evolve hydrogel based treatment systems from the lab-scale to practical applications. This review provides a coverage of the latest developments in the application of hydrogels for the adsorptive removal of aqueous pollutants. A holistic overview of different steps involved in the hydrogel based treatment systems is provided, and the influencing factors and mechanisms of pollutants removal are reviewed. Major challenges pertaining to adsorption kinetics, operational pH range, interference, and hydrogel recovery are examined. Important considerations such as stability and reusability of hydrogels and resource recovery are also discussed, for economic and sustainability concerns.
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•Applications of hydrogels in the removal of aqueous pollutants are reviewed.•Overview of steps involved in hydrogel based treatment process is provided.•Influencing factors and mechanisms of pollutants removal are reviewed.•Perspectives on current challenges and their solutions are presented.•Stability, reusability, and resource recovery are discussed.
•Modification of epoxy resin with Carboxyl terminated polyethylene glycol succinate (CTPS) to improve its toughness.•Epoxy modified with 5 wt.% CTPS (CPSE5) shows maximum elongation and highest ...adhesion strength among all the coating compositions.•CPSE5 coating gives long term corrosion protection among all coating compositions.
Epoxy resins despite having excellent adhesion to various substrates, good corrosion and chemical resistance are less suitable for high-performance applications, as they are poor in ductility. In the present study, carboxyl terminated polyethylene glycol adipiate (CTPA) and carboxyl terminated polyethylene glycol succinate (CTPS) modifiers were synthesised and then used to modify bisphenol-A epoxy resin to raise the latter’s toughness. The study showed that in both the cases, 5 wt.% addition gave rise to the highest toughness as well as corrosion protection against salt fog and synthetic sea water exposure. However, between the two modifications the epoxy resin modified with 5 wt.% CTPS gave a better performance and so was pigmented with a mixture of zinc phosphate and red iron oxide to obtain the paint. The study showed that the epoxy resin modified with 5 wt.% CTPS + 30 vol.% pigments gave rise to the highest toughness (flexibility), adhesion and corrosion resistance when applied on to mild steel panels.
Nanogels made of biomolecules are one of the potential candidates as a nanocarrier for drug delivery applications. The unique structural characteristics and excellent biocompatibility of DNA suggest ...that DNA nanogels would be an ideal candidate. Herein, a general design strategy for the crafting of DNA nanogels with controllable size using the multivalent host-guest interaction between β-CD functionalized branched DNA nanostructures as the host and a star-shaped adamantyl-terminated 8-arm poly(ethylene glycol) polymer as the guest is reported. Our results reveal that multivalent host-guest interactions are necessary for the nanogel formation. Nanogels exhibit excellent biocompatibility, good cell permeability and high drug encapsulation ability, which are promising features for their application as a drug carrier. The encapsulation of doxorubicin, an anticancer drug, inside the hydrophobic network of the nanogel and its delivery into cancer cells are also reported. We hope that the general design strategy demonstrated for the creation of DNA nanogels may encourage other researchers to use this approach for the design of DNA nanogels of other DNA nanostructures, and explore the potential of DNA nanogels in drug delivery applications.
Maintenance of root growth is essential for plant adaptation to soil drying. Here, we tested the hypothesis that auxin transport is involved in mediating ABA's modulation by activating proton ...secretion in the root tip to maintain root growth under moderate water stress.
Rice and Arabidopsis plants were raised under a hydroponic system and subjected to moderate water stress (−0.47 MPa) with polyethylene glycol (PEG). ABA accumulation, auxin transport and plasma membrane H+-ATPase activity at the root tip were monitored in addition to the primary root elongation and root hair density.
We found that moderate water stress increases ABA accumulation and auxin transport in the root apex. Additionally, ABA modulation is involved in the regulation of auxin transport in the root tip. The transported auxin activates the plasma membrane H+-ATPase to release more protons along the root tip in its adaption to moderate water stress. The proton secretion in the root tip is essential in maintaining or promoting primary root elongation and root hair development under moderate water stress.
These results suggest that ABA accumulation modulates auxin transport in the root tip, which enhances proton secretion for maintaining root growth under moderate water stress.
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