Mechanism insights into the histopathological changes of polypropylene microplastics induced gut and liver in zebrafish.

Microplastics (MPs), emerging as significant pollutants, have been consistently detected in aquatic environments, with the Yangtze River experiencing a particularly severe level of microplastic pollution, exceeding all other watersheds in China. Polypropylene (PP), the plastic most abundantly found in the middle and lower reaches of the Yangtze River Basin, has less comprehensive research results into its toxic effects. Consequently, the present investigation employed zebrafish as a model organism to delve into the toxicological impacts of polypropylene microplastics (PP-MPs) with a diameter of 5 µm across varying concentrations (300 mg/L and 600 mg/L). Using histopathological, microbiota profiling, and transcriptomic approaches, we systematically evaluated the impact of PP-MPs exposure on the intestine and liver of zebrafish. Histopathological analysis revealed that exposure to PP-MPs resulted in thinner intestinal walls, damaged intestinal mucosa, and hepatic cellular damage. Intestinal microbiota profiling demonstrated that, the richness, uniformity, diversity, and homogeneity of gut microbes significantly increased after the PP-MPs exposure at high concentration. These alterations were accompanied by shifts in the relative abundance of microbiota associated with intestinal pathologies, suggesting a profound impact on the intestinal microbial community structure. Concurrently, hepatic transcriptome analysis and RT-qPCR indicated that the downregulation of pathways and genes associated with cell proliferation regulation and DNA damage repair mechanisms contributed to hepatic cellular damage, ultimately exerting adverse effects on the liver. Correlation analysis between the intestinal microbiota and liver transcriptome profiles further highlighted significant associations between intestinal microbiota and the downregulated hepatic pathways. Collectively, these results provide novel insights into the subacute toxicological mechanisms of PP-MPs in aquatic organisms and highlight the need for further research on the ecological and health risks associated with PP-MPs pollution.

Photoelastic Organogel with Multiple Stimuli Responses.

The photoelastic effect has many uses in mechanics today, but it is usually disregarded in flexible materials. Using 2-phenoxyethyl acrylate as a monomer and 4-cyano-4'-pentylbiphenyl (5CB) as a solvent, a multiple responsive photoelastic organogel (PO) with strong birefringence but low modulus is created. 5CB is a liquid crystal molecule that does not participate in the polymerization process and is always present as tiny molecules in the polymer. It endows the PO low modulus and high birefringence, as well as the ability to drive the birefringence using an electric field. This PO not only has high sensitivity and fast response as a photoelastic strain sensor, but also has a very sensitive response to heat, especially in the range of human body temperature. It also has a high dielectric constant and a strong correlation between the interference color and the applied electric field, allowing for easy writing and erasure of encrypted data. This unique multisignal response feature and low modulus that mimics human skin bring up new opportunities in the potential applications such as multiple information encryption, anticounterfeiting, and multifunctional wearable sensors.

Enhanced Influenza Immunity by Nasal Mucosal Administration of the TPGS-Modified Liposomal Vaccine.

Influenza infection is difficult to prevent, control, and treat because of rapid viral mutation, fast disease progression, and high mortality. Vaccination is the main means by which to prevent and control influenza, but effectiveness is limited in that poor cellular uptake and weak immunogenicity of vaccines provides less than optimal host protection. Liposomal influenza vaccines are a promising strategy to overcome these limitations and the use of liposomal immune modulators and intranasal administration of liposomal influenza vaccines may be a means by which to improve influenza protection. The cationic lipids, i.e., dimethyldioctadecylammonium (DDA), 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), and D-α-tocopherol polyethylene glycol 1000 (TPGS) can form blank liposomes, which can incorporate influenza antigens to produce an influenza vaccine (DDA-DSPC-TPGS). Herein, this vaccine was shown to induce dendritic cell maturation, increase host cellular uptake of the vaccine, and enhance immune responses both in vitro and in vivo. The addition of TPGS, as an amphiphilic immune adjuvant, significantly reduced the toxicity of the DDA liposomal influenza vaccine. Further, the polyethylene glycol component and tocopherol structure of TPGS enhanced the cellular uptake of the vaccine by means of stealth properties and the capacity to inhibit cellular efflux. After nasal mucosal immunization, enhanced cellular uptake rates and abundant immune cells in the nasopharyngeal-associated lymphoid tissue promoted the production of immunoglobulin A, immunoglobulin G1, and interferon-γ, which in turn mediated a more robust immune response against influenza virus. In summary, the DDA-DSPC-TPGS influenza vaccine is a safe and effective means by which to activate the immune system. The results herein provide an effective strategy by which to overcome current difficulties associated with the prevention and treatment of influenza.

Electric Field Intensity Effects on the Microstructural Characteristics Evolution of Methyl Vinyl Silicone Rubber via Molecular Simulation.

During ultra high voltage (UHV) transmission, the discharge caused by high intensity electric fields aggravates the aging process of external insulation materials used for composite insulators. The microstructural characteristics of its base material polymer-methyl vinyl silicone rubber-are the key basis for the performance of insulation materials under electric field exposure. Based on molecular dynamics simulations, a molecular model of methyl vinyl silicone rubber was established. Mechanisms influencing the microstructure evolution under electric fields had been studied at the atomic level. The results showed that the initial reaction characteristics of silicone rubber molecules involve the violent vibrated of all the methyl and vinyl atoms, and shortening of the chemical bonds. The neighboring groups were close to each other and generated different amounts of -Si-Si- bonds. This promoted the helical shrinkage of the molecule, and protrusion of the middle of the molecule which presented an inverted U shape. The high electric field greatly reduced the total energy of molecules, and the potential energy in particular was more severely destroyed, resulting in degradation of its structure. Besides, as the electric field intensity increased, the elastic modulus of the molecule gradually increased. It was shown that high electric fields would make the stiffness of silicone rubber become larger, and the brittleness to become stronger, which reduced the mechanical properties of materials, accelerating its aging. The results provide a theoretical basis for establishing the connection between the micro appearance and macro characteristics of materials, as well as reference values for the optimization of base materials used for making composite insulators.

Honeycomb-Inspired Surface-Enhanced Raman Scattering Microarray for Large-Area Automated Testing of Urease in Saliva Samples.

Surface-enhanced Raman scattering (SERS) technology, as an important analytical tool, has been widely applied in the field of chemical and biomedical sensing. Automated testing is often combined with biochemical analysis technologies to shorten the detection time and minimize human error. The present SERS substrates for sample detection are time-consuming and subject to high human error, which are not conducive to the combination of SERS and automated testing. Here, a novel honeycomb-inspired SERS microarray is designed for large-area automated testing of urease in saliva samples to shorten the detection time and minimize human error. The honeycomb-inspired SERS microarray is decorated with hexagonal microwells and a homogeneous distribution of silver nanostars. Compared with the other four common SERS substrates, the optimal honeycomb-inspired SERS microarray exhibits the best SERS performance. The RSD of 100 SERS spectra continuously collected from saliva samples is 6.56%, and the time of one detection is reduced from 5 min to 10 s. There is a noteworthy linear relationship with a R2 of 0.982 between SERS intensity and urease concentration, indicating the quantitative detection capability of the urease activity in saliva samples. The honeycomb-inspired SERS microarray, combined with automated testing, provides a new way in which SERS technology can be widely used in biomedical applications.

3-D culture of human umbilical vein endothelial cells with reversible thermosensitive hydroxybutyl chitosan hydrogel.

The aim of this study was to present a non-trypsin 3D cell culture method with a reversible thermosensitive HBCS hydrogel. In this study, hydroxybutyl chitosan (HBCS) was synthesized by grafting hydroxybutyl groups on chitosan molecule chains. The prepared HBCS was water-soluble, and the reversible phase transformation temperature was 26 °C. Scanning electron microscope images illuminated the 3-D network of hydrogel formed irregular porous structure which ranged from 50-250 µm. Cell viability assay indicated that HBCS solution could promote the proliferation of human umbilical vein endothelial cells (HUVECs), and the boost of proliferation was enhanced with the increase of HBCS concentration. HBCS had no harm to the nitric oxide (NO) synthesis functionality of HUVECs. HUVECs could grow and reproduce inside the hydrogel, and showed good vitality after 14-days culture. Meanwhile, cells cultured inside the hydrogel could be passaged successively through the reversible phase transformation process of HBCS. The results revealed that HBCS have the potential to be used for 3-D cell culture without the use of trypsin.

Combination of a cationic complexes loaded with mRNA and α-Galactose ceramide enhances antitumor immunity and affects the tumor immune microenvironment.

mRNA vaccination is considered to be a promising strategy for tumor immunotherapy. Among, adequate antigen expression and regulation of tumor immune microenvironment are still the key to achieving therapeutic immounotherapy. In oreder to protect mRNA delivered to cells and reverse damaged dendritic cells(DCs), a novel vaccine delivery system composed of an α-Galactose ceramide/cationic liposome complex(α-GC-Lip) was constructed. The α-GC-liposome/protamine/mRNA vaccine complexes(α-GC-LPR) enabled the mRNA to be successfully translated into protein in the cytoplasm of antigen-presenting cells. Further, α-GC-LPR could stimulate dendritic cell maturation via significantly increasing the expression of bone marrow-derived cells(BMDCs) surface molecules and secretion of cytokines to improve the efficacy of immunotherapy. In vivo study, the α-GC-LPR was combined with programmed cell death protein 1(PD-1) inhibitor could activate natural killer cell(NK), T cells as well as significantly reduce the immunosuppression of immune cells, which induced strong antigen-specific immunity in breast cancer model. Our study indicated that the α-GC-LPR combined with immune checkpoint inhibitors as a potential design strategy to effectively enhance the antitumor immune response.

PREPARATION AND PROPERTIES OF COMPOUND ARNEBIAE RADIX MICROEMULSION GEL.

BACKGROUND: Compound Arnebiae radix oil has been clinically applied to treat burns and scalds for a long time. However, it is unstable and inconvenient to use. The aim of this study was to prepare a compound Arnebiae radix microemulsion gel for transdermal delivery system and evaluate its characteristics. MATERIALS AND METHODS: Based on the solubility of Shikonin, the active component of Arnebiae radix and the results of phase studies, adequate ratio of each component in microemulsion was determined. The optimized microemulsion gel was prepared using Carbomer 940. The gels were characterized in terms of appearance, preliminary stability test and the content of Shikonin in the compound Arnebiae radix microemulsion gel with HPLC analysis. RESULTS: The optimized conditions for preparing microemulsion were Tween-80, glycerin, isopropyl myristate (IPM) with the ratio of 6:3:2. The optimal microemulsion gel was obtained with Carbomer 940 (1.0%). CONCLUSION: The prepared compound Arnebiae radix microemulsion gel showed good stability over time. It is more convenience in application than the previous used formulations.

Polymer replicas of photonic porous silicon for sensing and drug delivery applications.

Elaborate one-dimensional photonic crystals are constructed from a variety of organic and biopolymers, which can be dissolved or melted, by templating the solution-cast or injection-molded materials in porous silicon or porous silicon dioxide multilayer (rugate dielectric mirror) structures. After the removal of the template by chemical dissolution, the polymer castings replicate the photonic features and the nanostructure of the master. We demonstrate that these castings can be used as vapor sensors, as deformable and tunable optical filters, and as self-reporting, bioresorbable materials.