Cross-linking Properties Research Articles

Preparation and evaluation of microcapsules of sodium alginate based on microfluidic technology

Many active ingredients in food products are destroyed by gastric acids and enzymes as they pass through the stomach, thereby reducing the desired effect of the target ingredient. In addition, traditional microcapsule preparation methods usually break up the dispersion by mechanical stirring or oscillation, which generates droplets of uneven size and inconsistent inclusion content, and mechanical external forces may cause denaturation and inactivation of active substances. This study aimed to use microfluidics to generate Oil-in-water-in-oil (O/W/O) droplet structures with good monodispersity and highly tunable properties, and to further prepare microcapsules with high encapsulation rate and targeted intestinal release by taking advantage of the cross-linking properties of alginate that reacts with Ca2+ under acidic conditions. Finally, the particle size distribution, release effect, encapsulation effect and oxidative stability of the core-shell microcapsules were evaluated. In this study, two types of microcapsules, homogeneous and core-shell microcapsules, were prepared by selecting tea polyphenols and vitamin E as models for hydrophilic and lipophilic bioactive compounds, respectively. Thin shell microcapsules with a shell thickness of about 25 μm were prepared using PDMS chip conditioning. Large microcapsules with a particle size of 230 μm were generated by using capillary glass tube chips, which had an excellent antioxidant property with a retention rate of 88.66 ± 1.25% of VE after 20 days of storage at 4 °C, while all of the VE was oxidized in the bare environment. In addition, in simulated gastric fluid, the release of VE was only about 20%, while in artificial intestinal fluid, the release was close to 100%, so the microcapsules also had intestinal targeting properties.

Walking a thin line between fixation and epitope binding - characterization of antigen retrieval methods suitable for eosinophil and HSV-2 staining in formalin-fixed female reproductive tissue.

Antibody-based fluorescence analysis of female reproductive tissues in research of sexually transmitted diseases allows for an in-depth understanding of protein localization, interactions, and pathogenesis. However, in many cases, cryosectioning is not compatible with biosafety regulations; at all times, exposure of lab personnel and the public to potentially harmful pathogens from biological infectious material must be avoided; thus, formaldehyde fixation is essential. Due to formaldehyde's cross-linking properties, protein detection with antibodies can be impeded. To allow effective epitope binding during immunofluorescence of formalin-fixed paraffin-embedded vaginal tissue, we investigated two antigen retrieval methods. We tested these methods regarding their suitability for automated image analysis, facilitating reproducible quantitative microscopic data acquisition in sexually transmitted disease research. Heat-based retrieval at 80°C in citrate buffer proved to increase antibody binding to eosinophil protein and HSV-2 visibly and tissue morphology best, and was the most efficient for sample processing and quantitative analysis.

Crosslinking ionic oligomers sol-gel synthesis of high-surface-area mesoporous magnesium carbonate and its general applicability

Mesoporous magnesium carbonate has been widely used in controlled release of drugs, adsorption or catalysis. In traditional methods, expensive alkoxide or MgO are usually employed as Mg-source to prepare mesoporous magnesium carbonate. Herein, based on the crosslinking property of ionic oligomers, a novel crosslinking ionic oligomer sol-gel method was proposed to prepare high-surface-area mesoporous magnesium carbonate using cheap MgCl2·6H2O and CO2 as material. (MgCO3)n crosslinking oligomer sols was produced based on the H-bond capping effects of ethanol and triethylamine. The evolution mechanism of crosslinking (MgCO3)n oligomer sols to gels was studied by using ATR-FTIR and NMR. The results indicated that with the slow volatilization of ethanol and triethylamine, a part of H-bond disappeared, which initiating the chain growth of (MgCO3)n oligomer molecules, and finally forming a crosslinking network. Combined with a CO2 critical point drying process, amorphous mesoporous magnesium carbonate nanoparticle with high surface area was obtained and characterized using ATR-FTIR, XRD, XPS, nitrogen adsorption/desorption analysis, SEM, TEM and EDS systematically. The specific surface area of magnesium carbonate reached 628 m2 g−1 when the n(TEA)/n(Mg2+) was 40:1. Moreover, the general applicability of this method was verified. Mesoporous sulfate and phosphate were synthesized, which indicating the crosslinking oligomer sol-gel chemistry provided a general strategy for the construction of mesoporous inorganic oxysalt materials. Our work has important guiding significance for the preparation of other mesoporous materials that using cheap inorganic salt as raw material.

Double networks hybrid hydrogels of silica nanoparticles/polyacrylamide: Network stiffness, viscoelastic, mechanical and adhesion properties

Today, the challenge of enhancing the strength and adhesion of the polyacrylamide hydrogel network is still a major concern in many applications. This study investigates the effect of silica nanoparticle concentration on the cross-linked polyacrylamide hydrogel’s gelation, viscoelastic, structural, and adhesion properties. The hybrid hydrogels were evaluated using DSC, XRD, SEM, and rheological analysis to determine their enthalpy of cross-linking, crystallinity, morphology, and elastic properties. The results of kinetic analysis confirmed the catalytic effect of silica nanoparticles on the gelation kinetics. A deviation from the elastic behavior of the unfilled hydrogel was found from the rheological studies. Using the Weibull Model to describe the creep test results showed a significant increase in retardation time with increasing silica nanoparticles content up to the percolation threshold of 0.24 wt.%. This confirmed the development of a more viscous behavior due to the formation of a physical network of nano-silica particles. Based on the DSC energy of hydrogels, both chemical and physical tie points (approximately 19 covalent crosslinking points) were calculated. The hydrogel containing 9 wt.% of silica nanoparticles demonstrated significant improvement in density, and adhesion to the metal surface by about 100% and 350%, respectively. As a result of this study, the hydrogel containing 9 wt% of silica nanoparticles (H9) is suggested for various field studies, such as oil well plugging industries.

Ceresin wax enhances hydrophobicity and density of bio-based polyurethane of controlled-release fertilizers: Streamlined production, improved nutrient release performance, and reduced cost

Bio-based coated controlled-release fertilizers (BCRFs) can significantly improve nutrient utilization and reduce pollution. However, challenges such as spray gun clogging, adhesion and tearing between fertilizers during the actual production of BCRFs pose a severe challenge to production chain development. In addition, the poor hydrophobicity and cross-linking properties of bio-based coatings severely affect the controlled release properties of BCRFs. Although some measures have been taken to ameliorate the above problems, the cumbersome and costly modification process is challenging to be applied on a large scale. Therefore, the primary goal of this work is to search for a more straightforward and efficient method of production and modification to address the aforementioned unresolved challenges in the field of CRFs. In this study, bio-based polyester polyol (BPP) was used as the base for polyurethane reaction, and low-viscosity castor oil (CO) was used as the modifier to reduce the viscosity of BPP. This led to the preparation of Inter-Modified Coated Controlled-Release Fertilizers (ICRFs) to prevent spray gun clogging. Building upon this, hydrophobic and dense wax-based coated fertilizer (WBCF) was prepared by modifying ICRF with Ceresin wax to alleviate the challenges associated with adhesion and tearing between fertilizer particles during the coating process. The WBCF exhibited remarkable controlled-release characteristics, with a nitrogen (N) release longevity of nearly 180 days, requiring only 3 % of the coating materials. This work provides a simple and efficient strategy for overcoming the key constraints in the development and production of CRFs and provides insights into developing green, low-cost fertilizers with excellent controlled-release properties.

Harnessing the Flexibility of Lightweight Cellulose Nanofiber Composite Aerogels for Superior Thermal Insulation and Fire Protection.

Thermally insulating materials from renewable and readily available resources are in high demand for ecologically beneficial applications. Cellulose aerogels made from lignocellulosic waste have various advantages. However, they are fragile and breakable when bent or compressed. In addition, cellulose aerogels are flammable and weather-sensitive. Hence, to overcome these problems, this work included the preparation of polyurethane (PU)-based cellulose nanofiber (CNF) aerogels that had flexibility, flame retardancy, and thermal insulation. Methyl trimethoxysilane (MTMS) and water-soluble ammonium polyphosphate (APP) were added to improve the cross-linking, hydrophobicity, and flame-retardant properties of aerogels. The flexibility of chemically cross-linked CNF aerogels is enhanced through the incorporation of polyurethane via the wet coagulating process. The aerogels obtained during this study have exhibited low weight (density: 35.3-91.96 kg/m3) together with enhanced hydrophobic properties, flame retardancy, and decreased thermal conductivity (26.7-36.7 mW/m K at 25 °C). Additionally, the flame-retardant properties were comprehensively examined and the underlying mechanism was deduced. The aerogels prepared in this study are considered unique in the nanocellulose aerogel category due to their integrated structural and performance benefits. The invention is considered to substantially contribute to the large-scale manufacture and use of insulation in construction, automobiles, and aerospace.

Features of printing textile materials with pigments and the use of water dispersions of synthetic copolymers

In pigment printing, a pressing issue is the search for new binders for printing inks. The work examines the search for accessible and cheap polymer preparations that have cross-linking properties and are capable of forming strong, elastic and transparent films to create an effective low-component and environmentally friendly pigment printing technology. The use of polyurethane dispersions in various proportions with additional cross-linking agents has been studied. They used methazine, carbamol GL, and PVA. For the Aquapol - Methazine mixture, it is necessary to use the ratio with the lowest content of thermosetting resin precondensates. When using PVA, the optimal ratio is 1:1. When adding Aquapol 12, the color fastness to dry rubbing and washing is 5 points. PVA increases the adhesion of the print to the fabric. In the case of PVA, the fingerboard is softer. With increasing concentration of PVA in the composition, the hardness either does not change or decreases. After modification of polyurethane dispersions with PVA, its use is economically beneficial.

Influences of amine/epoxide ratio on cross-linking structure and mechanical properties of cured hydrogenated epoxy resin sheets and single-lap joints

The influence of the amine/epoxide ratio (N–H/Ep.), controlled from 0.5 to 2.0, on the network structure and mechanical properties of cured epoxy resin (CER) was investigated using a cycloaliphatic epoxy and amine components, in a form of sheets and single-lap joints (SLJs). The cross-linking density and glass transition temperature of CER sheet was the highest at 1:1 stoichiometric N–H/Ep. ratio and became lower with being out of the ratio. On the contrary, tensile strength of sheet and shear strength of SLJ monotonically increased and decreased with an increase in amine content, respectively. Excess amine can work as fillers for sheets and made interfacial strength weaken between adherend and adhesive for SLJs. Changing the N–H/Ep. ratio can control the mechanical properties of not only sheets, but SLJs. Comparisons with mechanical properties of sheets and SLJs are quite helpful to design the high-performance adhesive.

Time domain NMR evaluation of thermal and thermochemical aging of nitrile rubber on crosslinking and mechanical properties

This study investigates the impact of aging on nitrile rubber (NBR) compositions under thermal and thermochemical aging conditions. The effects of aging were assessed using the 1H Double Quantum Time Domain NMR (DQ-NMR) technique, providing molecular-scale insights into average cross-link density, spatial heterogeneity, and network inelastic defects. The aging's influence on the macroscopic mechanical properties of NBR, including hardness, elongation, and stress at break, known to be closely related to cross-linking, was examined. It was observed that temperature-induced aging affected NBR differently based on the acrylonitrile content and solvent absorption capacity. 1H Double Quantum Time Domain NMR provided evidence of increasing heterogeneous cross-linking, which created a denser network structure. The changes in mechanical properties during aging were consistent with the NMR analyses, providing valuable insights for understanding, customizing, and predicting the service life of a specific O-Ring based NBR formulation.

An efficient protocol for extracting thylakoid membranes and total leaf proteins from Posidonia oceanica and other polyphenol-rich plants

BackgroundThe extraction of thylakoids is an essential step in studying the structure of photosynthetic complexes and several other aspects of the photosynthetic process in plants. Conventional protocols have been developed for selected land plants grown in controlled conditions. Plants accumulate defensive chemical compounds such as polyphenols to cope with environmental stresses. When the polyphenol levels are high, their oxidation and cross-linking properties prevent thylakoid extraction.ResultsIn this study, we developed a method to counteract the hindering effects of polyphenols by modifying the grinding buffer with the addition of both vitamin C (VitC) and polyethylene glycol (PEG4000). This protocol was first applied to the marine plant Posidonia oceanica and then extended to other plants synthesizing substantial amounts of polyphenols, such as Quercus pubescens (oak) and Vitis vinifera (grapevine). Native gel analysis showed that photosynthetic complexes (PSII, PSI, and LHCII) can be extracted from purified membranes and fractionated comparably to those extracted from the model plant Arabidopsis thaliana. Moreover, total protein extraction from frozen P. oceanica leaves was also efficiently carried out using a denaturing buffer containing PEG and VitC.ConclusionsOur work shows that the use of PEG and VitC significantly improves the isolation of native thylakoids, native photosynthetic complexes, and total proteins from plants containing high amounts of polyphenols and thus enables studies on photosynthesis in various plant species grown in natural conditions.

Fabrication of silicon-based nickel nanoflower-encapsulated gelatin microspheres as an active antimicrobial carrier

Local antibiotic application might mitigate the burgeoning problem of rapid emergence of antibiotic resistance in pathogenic microbes. To accomplish this, delivery systems must be engineered. Hydrogels have a wide range of physicochemical properties and can mimic the extracellular matrix, rendering them promising materials for local antibacterial agent application. Here, we synthesized antibacterial silicon (Si)-based nickel (Ni) nanoflowers (Si@Ni) and encapsulated them in gelatin methacryloyl (GelMA) using microfluidic and photo-crosslink technology, constructing uniform micro-sized hydrogel spheres (Si@Ni-GelMA). Si@Ni and Si@Ni-GelMA were characterized using X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Injectable Si@Ni-GelMA exhibited excellent antibacterial activities owing to the antibiotic effect of Ni against Pseudomonas aeruginosa, Klebsiella pneumoniae, and methicillin-resistant Staphylococcus aureus, while showing negligible cytotoxicity. Therefore, the Si@Ni-GelMA system can be used as drug carriers owing to their injectability, visible light-mediated crosslinking, degradation, biosafety, and superior antibacterial properties.

Chemical, thermal and film properties of metal cross-linking fluorinated polyacrylate colloid prepared via semi-continuous seeded emulsion polymerization

The metal cross-linking fluorinated polyacrylate colloid has a high cross-linking density, high transparency, high heat resistance and hydrophobicity. In this paper, the metal cross-linking fluorinated polyacrylate colloid is synthesized via the semi-continuous seeded emulsion polymerization technology, which uses the self-made magnesium acrylate, calcium acrylate and zinc acrylate as metal crosslinker and dodecafluoroheptyl methacrylate as a fluorine monomer. In this study, the ablation effect of the metal ions is weakened by the increased amount of environmentally friendly and polymerizable anion emulsifier DNS-86. The demulsification phenomenon of emulsion is successfully overcome through destroying the double layer structure of micelles or colloid particles by polyvalent metal ions. The colloidal particle size is smaller and the particle size distribution of the colloid is more uniform. Colloidal film has a good hydrophobicity and the glass transition temperature and the thermal decomposition temperature are high.

Effect of chitosan crosslinking time on the structure and antifouling performance of polyvinylidene fluoride membrane by surface gelation-immersion precipitation phase inversion.

Polyvinylidene fluoride (PVDF) porous membrane was prepared by a two-step method of surface gelation-immersion precipitation phase inversion. Chitosan/acetic acid solution and glutaraldehyde aqueous solution were sequentially sprayed onto the surface of the PVDF solution film, with chitosan crosslinking and gelation occurring simultaneously on the film surface. The solution film was then immersed in a coagulation bath to obtain a modified PVDF porous membrane. The effect of the crosslinking time of chitosan and glutaraldehyde on the structure and properties of the PVDF porous membrane was discussed. The results showed that with the prolongation of crosslinking time, the surface structure of the membrane changed from a dense skin layer to a porous structure; the porosity and the mean pore size of the modified PVDF membranes increased first and then decreased, and the contact angle gradually decreased. When the crosslinking time extended to 15 min, the water flux of modified membrane (M153) reached a maximum value. BSA dynamic cyclic filtration experiment showed that the retention rate (R) of the modified membrane was significantly improved, compared to 68.3% retention rate of the blank membrane (M000), but the crosslinking time had little effect on the retention rates of the four modified membranes. The antifouling data showed that the flux recovery rate of the blank membrane was 73.0%, while the flux recovery rate of the modified membrane can reach as high as 84.40%, and the irreversible pollution rate of the blank membrane was 27.7%, while the irreversible pollution rate of the modified membrane reduced to 15.6%. These results indicated that, after surface chitosan crosslinking, the hydrophilicity and antifouling properties of PVDF membranes were improved. PRACTITIONER POINTS: Modified PVDF membranes with crosslinking CS coating were prepared by a two-step method of surface gelation-immersion precipitation phase inversion. -OH groups and -NH2 groups of CS coating improve the hydrophilicity and the antifouling property of modified PVDF membranes. Modified PVDF membranes had larger mean pore size and higher porosity than unmodified membrane. Flux recovery rates of the modified membranes were higher than that of unmodified membrane. Pollution degree, reversible pollution rate, and irreversible pollution rate of modified membranes were lower than those of unmodified membrane.

The effect of citric acid concentrations on the mechanical, thermal, and structural properties of starch edible films

SummaryThis study investigated the effects of citric acid on the properties of edible tapioca starch films plasticised with glycerol. These films were formed using 5% tapioca (w/w of water); 1%, 3%, 5%, 7% and 9% citric acid (w/w of starch); and 2.2% glycerol (w/w of water). Native starch films formed using 5% tapioca and 2.2% glycerol were used as the control. The properties tested included the degree of crosslinking, thermal stability, crystallinity and mechanical properties. These were evaluated using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR‐FTIR), X‐Ray diffraction (XRD), thermal gravimetric analysis (TGA) and tensile profile analysis (TPA). The FTIR results provided information about the nature of the crosslinking in the films, while TGA showed that increasing the citric acid concentration reduced the physical decomposition temperature of the materials. Films containing 9% citric acid had the highest degree of esterification and crosslinking, while those containing 7% citric acid had the lowest heat‐related weight loss that correlated with the degree of crosslinking. The weight loss among all six samples was the greatest in the temperature range 260 °C–350 °C where a total of 60% weight loss occurred. The XRD results showed that films containing 3% citric acid had the lowest crystallinity while the native starch films had the highest crystallinity. The TPA analyses showed that films containing 5% citric acid had the greatest influence on improving the tensile strength and elastic modulus, while also having the best impact on lowering the elongation. Tensile strength values recorded for films containing 0%, 1%, 3%, 5%, 7% and 9% citric acid were 5.327, 7.813, 8.688, 12.855, 14.549 and 11.614 MPa. Similarly, when citric acid concentration increased from 3% to 5%, the elastic modulus significantly increased from 831.058 to 2255.691 MPa. This study demonstrated that the physicochemical properties of tapioca starch‐based films could be modified by the incorporation of citric acid.

Recent advances in non-perfluorinated sulfonic acid proton exchange membranes in the energy field

Introduce the latest progress of non-perfluorinated sulfonic acid proton exchange membranes from the aspects of crosslinking methods, properties and applications.

Mononuclear copper(II) complexes with polypyridyl ligands: synthesis, characterization, DNA interactions/cleavages and in vitro cytotoxicity towards human cancer cells.

DNA being the necessary element in cell regeneration, controlled cellular apoptosis via DNA binding/cleaving is considered an approach to combat cancer cells. The widely prescribed metallodrug cisplatin has shown interactions with the guanine-N7 center, and a plethora of complexes are continually developed to enhance crosslinking properties as well as covalent and non-covalent interactions. Two pentadentate ligands, L1 (1-(6-(1H-benzo[d]imidazol-2-yl)pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine) and L2 (1-(6-(1-methyl-1H-benzo[d]imidazol-2-yl)pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine), were synthesized together with their respective copper(II) complexes [1](ClO4)2 and [2](ClO4)2, which crystallized in a trigonal bipyramidal fashion. Different analytical and spectroscopic methods confirmed their formation, and their redox behaviour was also examined. The interactions of salmon sperm DNA (ss-DNA) with these two complexes were explored using absorbance spectroscopy, and they both exhibited a binding affinity (Kb) of ∼104 M-1. Fluorescence quenching experiments with ethidium bromide (EB)-bound DNA (EB-DNA) were also performed, and Stern-Volmer constant (KSV) values of 6.93 × 103 and 2.34 × 104 M-1 for [1](ClO4)2 and [2](ClO4)2, respectively, were obtained. Furthermore, DNA conformational changes due to the interactions of both complexes were validated via circular dichroism. We also assessed the DNA cleavage property of these complexes, which resulted in the linearization of circular plasmid DNA. This finding was supported by studying the growth of MDA-MB-231 breast cancer cells upon treatment with both Cu(II) complexes; IC50 values of 5.34 ± 1.02 μM and 0.83 ± 0.18 μM were obtained for [1](ClO4)2 and [2](ClO4)2, respectively. This validates their affinity towards DNA, and these insights can be further utilized for non-platinum based economical metallodrug development based on first row transition metals.

Ultraviolet light irradiated high‐efficiency crosslinking and insulating properties of LLDPE/EPDM blends

AbstractUltraviolet light (UV) irradiation crosslinked linear low‐density polyethylene (LLDPE)/ethylene propylene diene monomer (EPDM) composites with different blending ratios were prepared using benzophenone (BP) as photoinitiator and triallyl isocyanurate (TAIC) as crosslinking agent. The irradiation time was determined, the effects of rubber‐plastic ratio on the crystallization behaviors, mechanical properties, crosslinking properties and electrical properties of LLDPE/EPDM composites were investigated. The results show that with the increase of EPDM content, the crystalline structure of LLDPE/EPDM composite become looser and the crystallinity decreased. The blending of EPDM and LLDPE results in two different aggregation states of the same crystalline form. With the increase of LLDPE content, the crosslinking efficiency, tensile strength, and energy storage modulus show a significant upward trend. When two polymers simultaneously exist in the material, if the difference between the contents of two polymers is large, the breakdown strength of the composite is relatively lower. The relaxation polarization of LLDPE/EPDM at low frequencies increases with the content of EPDM, thus leading to the increase of loss factor at low frequencies. A novel UV crosslinked modified EPDM insulating material with high production efficiency and improved insulation performances has been developed for use as an insulating layer for flexible power cables.

Self-healing recyclable polymers based on azobenzenes with thermoset like behaviour

Self-healing materials are considered intelligent materials capable of recovering their original shapes from damaged or distorted forms after exposure to specific stimuli, such as chemicals, heat, moisture, or light. The utilization of thermoreversible crosslinks in polymer networks has garnered increasing interest as a method to create such materials. In these polymers, damage can be repaired simply by heating them above a gel-liquid transition temperature. Upon cooling, the material regains its previous cross-linked properties. However, finding alternative external stimuli other than heat presents an intriguing challenge. Among the various possibilities, light is the preferred choice due to its potential for remote and spatially-controlled activation. Additionally, the process can be easily paused and resumed by turning the excitation light on and off.Furthermore, the photo-switching of the glass transition temperature (Tg) in azobenzene-containing polymers induces reversible transitions from a solid to a liquid state. These reversible trans-to-cis transitions are triggered by UV and visible light irradiation. This phenomenon offers a novel approach to designing healable polymers and allows for precise control over the mechanical properties of polymers with spatio-temporal resolution.The main objective of this study is to investigate the feasibility of using light as a self-healing trigger in a recyclable polymer based on physically cross-linked epoxy/amine formulations. To achieve this goal, the matrix was modified with 4-phenylazophenol (PAP), which forms homogeneous blends with the polymer through hydrogen bond interactions. Films were prepared and characterized using various experimental techniques. Polymerization kinetics of samples with and without PAP was determined using FTIR, which was also employed for characterizing the final materials. Tg of the resulting products was measured using DSC, revealing a decrease in its value for PAP-modified samples. The transition from a solid to a liquid state during UV light irradiation was observed using rheometric analysis. The reversible photoisomerization behaviour of epoxy/amine/PAP was investigated using UV–visible spectroscopy in films prepared by spin-coating THF solutions.The ability of the material to self-heal at room temperature using light as a remote source was confirmed through TOM (Transmission Optical Microscopy) observations and quantified by profilometric measurements. In addition, surface mechanical properties were evaluated in order to determine the effect of the incorporation of the PAP, and the ability of the repaired material to recover its properties. Promising findings indicate that this recyclable polymer holds significant potential for multiple applications where its self-healing ability will be of great importance.

Thermo-accelerated curing of transparent glass-glass bondings through in-situ heat generation in the adhesive joint

ABSTRACT Bonding glass is challenging due to the brittle properties of the material. At the same time, it is interesting for transparent architectural applications, as the entire construction appears as a uniform surface without disturbance. Many adhesives are available for this purpose, whereby epoxy resins and polyurethanes fulfill the highest structural requirements due to their crosslinking properties. In addition, the curing of both can be accelerated by heat, so that short economic cycle times can be achieved. However, in conventional heating the entire construction element, often several meters long, has to be placed in an oven. This results again in long curing cycles, high-energy consumption and high costs. Induction or resistance methods achieve more targeted heating, but these require components at the adhesive joint that can be activated. Electrically conductive or magnetizable fillers are non-transparent and metallic substrates such as brackets or fixings do not exist on glass-glass bondings. Therefore, this study investigated heat generation on little-visible, metallic inserts and glass coatings. Different adhesives were analyzed for their accelerated heat curing properties and the resulting bond strength. A fast cured, highly transparent joint could be achieved with the combination of an epoxy resin and the resistant heating of a silver coating.

Injectable Decellularized Extracellular Matrix-Based Bio-Ink with Excellent Biocompatibility for Scarless Urethra Repair.

In recent years, decellularized extracellular matrices (dECM) derived from organs have attracted much attention from researchers due to their excellent biocompatibility, capacity to promote cell proliferation and migration, as well as pro-vascularization. However, their inferior mechanical properties, slow cross-linking, weak strengths, and poor supporting properties remain their inevitable challenges. In our study, we fabricated a novel dECM hydrogel with better crosslinking strength and speed, stronger support properties, and better mechanical properties. The hydrogel, which we named gelatin-based dECM powder hydrogel (gelatin-dECM hydrogel), was prepared by mixing dECM microparticles in gelatin solution and adding certain amount of 1-Ethyl-3-(3-dimethyl-aminopropyl-1-carbodiimide) (EDC) and N-hydroxysuccinimide (NHS). We evaluated the utility of this hydrogel by assessing the degradation rate, mechanical properties, and biocompatibility. The results showed that the gelatin-dECM hydrogel has high mechanical properties and biocompatibility and also has the ability to promote cell proliferation and migration. After injection of this hydrogel around the surgical sites of urethras in rabbits, the incorporation of dECM powder was demonstrated to promote angiogenesis as well as scarless repair by histological sections after surgery. The application of this novel hydrogel provides a new perspective for the treatment of post-traumatic urethral stricture.