Improving the properties of fish skin collagen/silk fibroin dressing by chemical treatment for corneal wound healing

Natural biomaterials are crucial in ocular tissue engineering because they allow cells to proliferate, differentiate, and stratify while maintaining the typical epithelial phenotype. In this study, membranes as dressings were formed from silk fibroin and collagen (Co) extracted from fish skin and then modified with carbodiimide chemical cross linker in different concentrations. The samples were evaluated by different analyses such as structural, physical (optical, swelling, denaturation temperature, degradation), mechanical, and biological (viability, cell adhesion, immunocytochemistry) assays. The results showed that all membranes have excellent transparency, especially with higher silk fibroin content. Increasing the cross linker concentration and the ratio of silk fibroin to Co increased the denaturation temperature and mechanical strength and, conversely, reduced the degradation rate and cell adhesion. The samples did not show a significant difference in toxicity with increasing cross linker and silk fibroin ratio. In general, samples with a low silk fibroin ratio combined with cross linker can provide desirable properties as a membrane for corneal wound healing.     

Silk proteins in reconstructive surgery: Do they possess an inherent antibacterial activity? A systematic review

The field of reconstructive surgery encompasses a wide range of surgical procedures and regenerative approaches to treat various tissue types. Every surgical procedure is associated with the risk of surgical site infections, which are not only a financial burden but also increase patient morbidity. The surgical armamentarium in this area are biomaterials, particularly natural, biodegradable, biocompatible polymers, including the silk proteins fibroin (SF) and sericin (SS). Silk is known to be derived from silkworms and is mainly composed of 60–80% fibroin, which provides the structural form, and 15–35% sericin, which acts as a glue-like substance for the SF threads. Silk proteins possess most of the desired properties for biomedical applications, including biocompatibility, biodegradability, minimal immunogenicity, and tunable biomechanical behaviour. In an effort to alleviate or even prevent infections associated with the use of biomaterials in surgery, antibacterial/antimicrobial properties have been investigated in numerous studies. In this systematic review, the following question was addressed: Do silk proteins, SF and SS, possess an intrinsic antibacterial property and how could these materials be tailored to achieve such a property?     

Neem (Azadirachta Indica) and silk fibroin associated hydrogel: Boon for wound healing treatment regimen

Background & ObjectivesWound healing is the complex physiological process of replacing damaged cells or tissue layers. The neem (Azadirachta Indica) has a variety of biological activities, which may hasten the rate at which the wound healing mechanism occurs. Silk fibroin is a biomaterial that is reported for its tissue regeneration activity. So, the present study was designed to assess the effectiveness of a hydrogel comprising neem and silk fibroin biomaterials for the treatment of wounds.MethodsTopical neem hydrogels (N-HG) with and without silk fibroin (N-SFB-HG) were prepared using neem extract, silk fibroin, and guar gum, which act by entrapping the components by forming a gel. Evaluation tests such as Fourier transform infrared spectroscopy (FT-IR), visual emergence, pH, rheological behavior, spreading capacity, drug content, skin irritation, anti-microbial action, in vivo wound healing activity, and stability were carried out.ResultsThe FT-IR results showed no chemical interaction between the constituents. The formed hydrogels had pH values of 5.87 ± 0.3 for N-HG and 5.76 ± 0.2 for N-SFB-HG. The preferred topical gel viscosity was observed in the N-HG (54.2 ± 3.2cPs) and N-SFB-HG (59.9 ± 4.8cPs) formulations. The formulated hydrogels were sterile and did not irritate the skin. The in vivo wound healing investigation results reveal that the N-SF-HG treatment speeds up the regeneration of the injured area faster when compared to control and N-HG treated groups.Interpretation & ConclusionThese results support the efficacy of the topical hydrogel formulation, including neem and silk fibroin. Therefore, the neem-silk fibroin hydrogel formulation is a therapeutically viable choice that, following necessary clinical research, might be utilized in novel formulations for managing chronic wounds.     

Fabrication of biologically inspired electrospun collagen/silk fibroin/bioactive glass composited nanofibrous to accelerate the treatment efficiency of wound repair

A triple-layer matrix Collagen/Silk fibroin/Bioactive glass composited Nanofibrous was fabricated by linking electrospinning and freeze-drying systems, this typical three layered composite with a nanofibrous fragment as the key (top) layer, middle portion as inferior, and a spongy porous fragment as the third (bottom) deposit to develop the synergistic effect of composite materials resultant to physical and biological performances. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy were used to assess the final material's physicochemical properties (SEM). The triple-layer matrix had a nanofibrous and porous structure, which has qualities including high porosity, swelling, and stability, which are important in soft-tissue engineering. NIH 3 T3 fibroblast and humanoid keratinocyte (HaCaT) cell lines were also used to investigate the matrix's in vitro biological and fluorescent capabilities, which showed excellent cell adherence and proliferation across the composite layers. The synergistic arrangement of nanofibrous substantial deposition onto collagenous with silk fibroin candidates has therefore proven effective in the construction of a tri-layer matrix for skin-tissue-engineering applications.     

Rapid and repeatable fabrication of high A/R silk fibroin microneedles using thermally-drawn micromolds

Thermal drawing is a versatile rapid prototyping method that can freely form microneedle (MN) structures with ultra-high aspect ratio without relying on any complex and expensive process. However, it is still challenging to repeatedly produce MNs with identical shapes using this thermal drawing due to small fluctuations in processing conditions such as temperatures, drawing speeds, drawing heights, or parallelism in the drawing setup. In addition, thermal drawing is only applicable to thermoplastic materials and most natural biomaterials are incompatible with this method. Thus, we propose use of thermal drawing to fabricate master molds with high aspect ratios and replicate the shape by micromolding. In this work, high A/R MNs with various body profiles were fabricated by thermal drawing and replicated to silk fibroin (SF) MNs multiple times using micromolding. The original MN shape was precisely copied to the SF MNs. Methanol treatment enhanced the mechanical strength of SF MNs up to about 113% more depending on the treatment duration. We also demonstrated that methanol exposure time could effectively control drug release rates from SF MNs.     

丝素蛋白表面微观形貌对血管内皮细胞增殖功能的影响

目的:研究4种不同微观形貌的丝素蛋白膜对血管内皮细胞生长和增殖的影响,以寻找理想的丝素蛋白表面形貌,为生物材料应用于血管腔内治疗提供新的思路.方法:采用软印刷技术制备各种微观形貌的丝素蛋白膜,镜下观察丝素蛋白膜的不同微观形貌对血管内皮细胞形态以及行为的影响,采用磺基罗丹明B(sulforhodamine B,SRB)法观察丝素蛋白表面微观形貌对血管内皮细胞活性的影响.结果:内皮细胞在丝素蛋白材料上可以贴附生长,不同方式的表面微观形貌雕刻对于血管内皮细胞生长活性的影响不同；形貌2、3、4效果明显好于对照组(P＜0.05),形貌2雕刻的细胞生长优势最为明显；形貌5雕刻效果与对照组比较,差异无统计学意义(P＞0.05).结论:丝素蛋白覆膜材料能支持血管内皮细胞的正常生长和增殖,并可以通过丝素蛋白膜表面的微观形貌影响血管内皮细胞的形态及生物学行为.