Designing hybrid materials with multifunctional interfaces for wound dressing, electrocatalysis, and chemical separation

Polymer-Based Hydrogel Loaded with Honey in Drug Delivery System for Wound Healing Applications

Excellent wound dressings should have crucial components, including high porosity, non-toxicity, high water absorption, and the ability to retain a humid environment in the wound area and facilitate wound healing. Unfortunately, current wound dressings hamper the healing process, with poor antibacterial, anti-inflammatory, and antioxidant activity, frequent dressing changes, low biodegradability, and poor mechanical properties. Hydrogels are crosslinked polymer chains with three-dimensional (3D) networks that have been applicable as wound dressings. They could retain a humid environment on the wound site, provide a protective barrier against pathogenic infections, and provide pain relief. Hydrogel can be obtained from natural, synthetic, or hybrid polymers. Honey is a natural substance that has demonstrated several therapeutic efficacies, including anti-inflammatory, antibacterial, and antioxidant activity, which makes it beneficial for wound treatment. Honey-based hydrogel wound dressings demonstrated excellent characteristics, including good biodegradability and biocompatibility, stimulated cell proliferation and reepithelization, inhibited bacterial growth, and accelerated wound healing. This review aimed to demonstrate the potential of honey-based hydrogel in wound healing applications and complement the studies accessible regarding implementing honey-based hydrogel dressing for wound healing.

Near-infrared light-responsive multifunctional hydrogel releasing peptide-functionalized gold nanorods sequentially for diabetic wound healing

Treatment for chronic diabetic wounds remains a clinical challenge. Wound healing process occurs in three phases: inflammation, proliferation and remodeling. Several factors including bacterial infection, decreased local angiogenesis and diminished blood supply delay wound healing. There is an urgent need to develop wound dressings with multiple biological effects for different stages of diabetic wound healing. Here, we develop a multifunctional hydrogel with two-stage sequential release upon near-infrared (NIR) stimulation, antibacterial activity and pro-angiogenic efficacy. This hydrogel consists of covalently crosslinked bilayer structure, with the lower thermoresponsive poly(N-isopropylacrylamide)/gelatin methacrylate (NG) layer and the upper highly stretchable alginate/polyacrylamide (AP) layer embedding different peptide-functionalized gold nanorods (AuNRs) in each layer. Antimicrobial peptide-functionalized AuNRs released from NG layer exert antibacterial effects. After NIR irradiation, the photothermal transition efficacy of AuNRs synergistically enhances bactericidal efficacy. The contraction of thermoresponsive layer also promotes the release of embedded cargos during early stage. The pro-angiogenic peptide-functionalized AuNRs released from AP layer promote angiogenesis and collagen deposition by accelerating fibroblast and endothelial cell proliferation, migration and tube formation during the subsequent healing phases. Therefore, the multifunctional hydrogel with effective antibacterial activity, pro-angiogenic efficacy and sequential release behaviors is a potential biomaterial for diabetic chronic wound healing.

Hybrid-Based Wound Dressings: Combination of Synthetic and Biopolymers

Most commercialized wound dressings are polymer-based. Synthetic and natural polymers have been utilized widely for the development of wound dressings. However, the use of natural polymers is limited by their poor mechanical properties, resulting in their combination with synthetic polymers and other materials to enhance their mechanical properties. Natural polymers are mostly affordable, biocompatible, and biodegradable with promising antimicrobial activity. They have been further tailored into unique hybrid wound dressings when combined with synthetic polymers and selected biomaterials. Some important features required in an ideal wound dressing include the capability to prevent bacteria invasion, reduce odor, absorb exudates, be comfortable, facilitate easy application and removal as well as frequent changing, prevent further skin tear and irritation when applied or removed, and provide a moist environment and soothing effect, be permeable to gases, etc. The efficacy of polymers in the design of wound dressings cannot be overemphasized. This review article reports the efficacy of wound dressings prepared from a combination of synthetic and natural polymers.

Preparation of stretchable composite film and its application in skin burn repair

The poor elasticity of wound dressings often leads to wound healing failure due to rupture and fall off. In this study, the composite films of zein and hydrogel poly (acrylic acid) were developed in order to obtain stretchable wound dressing for skin burn repair. The mechanical test revealed that the maximum elongation of break of composite films could reach 349.76% when the mass ratio of zein to poly (acrylic acid) was 1.5. SEM and FTIR analysis demonstrated the good elasticity of composite films might be due to the formation of a dense structure and the strong interaction between zein and poly (acrylic acid). Interestingly, the composite films exhibited great adhesiveness to human finger skin and stretchable ability under strenuous joint exercise. CCK-8 assay and fluorescence staining showed that the composite films and their extract had good cytocompatibility on human foreskin fibroblasts (L929) cells. The in vivo experiment on rat's skin burning model indicated that the composite films could promote wound healing and collagen synthesis by comparison with commercial gauze. It could be concluded that the stretchable composite films of zein and hydrogel poly (acrylic acid) had the potential as the wound dressing.

W doping dominated NiO/NiS2 interfaced nanosheets for highly efficient overall water splitting

Constructing high-efficiency electrocatalysts is vital towards electrocatalytic water splitting, but it remains a challenge. Although Ni-based materials have drawn extensive attention as highly active catalysts, the relatively limited electroactive sites in Ni-based catalysts still remains a great issue. In order to further boost the electrocatalytic performances, heteroatom doping and interface engineering are usually adopted for modification. Here, a new strategy is developed to construct W doped NiO/NiS₂ interfaced nanosheets directly on carbon sheet, which is working as efficient and bifunctional electrocatalysts for overall water splitting. W doped NiO nanosheets are directly constructed on the carbon sheet by the hydrothermal and annealing processes. After that, W-NiO was subjected to Ar plasma assisted sulfuration treatment for forming W doped NiO/NiS₂ interfaced nanosheets. Based on systematic investigations, we find that W doping can effectively induce the modified electronic structure of Ni to boost the intrinsic activities in NiO/NiS₂. Further, forming NiO/NiS₂ nanointerfaces can also provide rich electroactive sites and boost the charge transfer rate. Consequently, W doped NiO/NiS₂ exhibits the much enhanced performances for overall water splitting. As a bifunctional electrode, W-NiO/NiS₂ demonstrates a remarkable activity with a 1.614 V cell voltage at 10 mA cm^-2 for overall water splitting.

Preparation of the Hybrids of Hydrotalcites and Chitosan by Urea Method and Their Antimicrobial Activities

Hybrid nano-supra molecular structured materials can boost the functionalityof nano- or supra-molecular materials by providing increased reactivity and conductivity, or by simply improving theirmechanical stability. Herein, the studies in materials science exploring hybrid systems are investigated from the perspective of two important related applications: healthcare andfood safety.Interfacing phase strategy was applied, and ZnAl layered double hydroxide-chitosan hybrids, prepared by the urea method (U-LDH/CS), were successfully synthesized under the conditions of different chitosan(CS) concentrations with a Zn/Al molar ratio of 5.0. The structure and surface properties of the U-LDH/CS hybrids were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer(FTIR), scanningelectronmicroscopy(SEM), ultravioletvisible(UV-Vis), and zero point charge (ZPC) techniques, where the effect of CS concentration on the structure and surface properties was investigated. The use of the U-LDH/CS hybrids as antimicrobial agents against Escherichia coli, Staphylococcus aureus,and Penicilliumcyclopiumwasinvestigated in order to clarify the relationship between microstructure and antimicrobial ability. The hybrid prepared in a CS concentration of 1.0 g∙L^-1 (U-LDH/CS₁) exhibited the best antimicrobial activity and exhibited average inhibition zones of 24.2, 30.4, and 22.3mm against Escherichia coli, Staphylococcus aureus, and Penicilliumcyclopium, respectively. The results showed that the appropriate addition of CS molecules could increase antimicrobial ability against microorganisms.

Use of Nanoparticles in Tissue Engineering and Regenerative Medicine

Advances in nanoparticle (NP) production and demand for control over nanoscale systems have had significant impact on tissue engineering and regenerative medicine (TERM). NPs with low toxicity, contrasting agent properties, tailorable characteristics, targeted/stimuli-response delivery potential, and precise control over behavior (via external stimuli such as magnetic fields) have made it possible their use for improving engineered tissues and overcoming obstacles in TERM. Functional tissue and organ replacements require a high degree of spatial and temporal control over the biological events and also their real-time monitoring. Presentation and local delivery of bioactive (growth factors, chemokines, inhibitors, cytokines, genes etc.) and contrast agents in a controlled manner are important implements to exert control over and monitor the engineered tissues. This need resulted in utilization of NP based systems in tissue engineering scaffolds for delivery of multiple growth factors, for providing contrast for imaging and also for controlling properties of the scaffolds. Depending on the application, materials, as polymers, metals, ceramics and their different composites can be utilized for production of NPs. In this review, we will cover the use of NP systems in TERM and also provide an outlook for future potential use of such systems.

A new alternative insight of nanoemulsion conjugated with κ-carrageenan for wound healing study in diabetic mice: In vitro and in vivo evaluation

Astaxanthin and alpha-tocopherol have attracted great attention because of their properties for the management of wound healing in diabetics. This study aimed to investigate the wound healing study of astaxanthin and alpha-tocopherol with κ-carrageenan nanoemulsion (AS-TP@KCNE) and to perform a histopathological study on streptozotocin (STZ)-induced diabetic mice. AS-TP@KCNE were also evaluated with aim of maintaining an effective and prolonged antidiabetic potential. KC@SENE and KC@USNE were obtained by spontaneous and ultrasonication emulsification methods and were characterized for stability, pH, particle size, and zeta potential by standard analysis. In vitro cytotoxicity and wound healing results demonstrated less toxicity and faster cell migration for the nanoemulsions at different concentrations. Based on the promising results, transdermal administration of AS-TP@KCNE can significantly restore the body weight, reduce fasting blood glucose levels, and improve glucose tolerance, which improved the ability to quickly heal of wounds in diabetic mice compared to control. In conclusion, the present study shows that the AS-TP@KCNE are biocompatible and possess healing properties that accelerate wound closure and exhibited better control of hyperglycemia and more superbly reversed the diabetes mellitus complications than STZ-induced diabetic mice. These results suggested that AS-TP@KCNE could be a promising platform for wound healing applications for diabetics.

Analysis of In Vitro Osteoblast Culture on Scaffolds for Future Bone Regeneration Purposes in Dentistry

One of the main focuses of tissue engineering is to search for tridimensional scaffold materials, complying with nature's properties for tissue regeneration. Determining material biocompatibility is a fundamental step in considering its use. Therefore, the purpose of this study was to analyze osteoblast cell adhesion and viability on different materials to determine which was more compatible for future bone regeneration. Tridimensional structures were fabricated with hydroxyapatite, collagen, and porous silica. The bovine bone was used as material control. Biocompatibility was determined by seeding primary osteoblasts on each tridimensional structure. Cellular morphology was assessed by SEM and viability through confocal microscopy. Osteoblast colonization was observed on all evaluated materials' surface, revealing they did not elicit osteoblast cytotoxicity. Analyses of four different materials studied with diverse compositions and characteristics showed that adhesiveness was best seen for HA and viability for collagen. In general, the results of this investigation suggest these materials can be used in combination, as scaffolds intended for bone regeneration in dental and medical fields.