Silk Fibroin-Based Biomaterials for Tissue Engineering Applications

Tissue engineering (TE) involves the combination of cells with scaffolding materials and appropriate growth factors in order to regenerate or replace damaged and degenerated tissues and organs. The scaffold materials serve as templates for tissue formation and play a vital role in TE. Among scaffold materials, silk fibroin (SF), a naturally occurring protein, has attracted great attention in TE applications due to its excellent mechanical properties, biodegradability, biocompatibility, and bio-absorbability. SF is usually dissolved in an aqueous solution and can be easily reconstituted into different forms, including films, mats, hydrogels, and sponges, through various fabrication techniques, including spin coating, electrospinning, freeze drying, and supercritical CO₂-assisted drying. Furthermore, to facilitate the fabrication of more complex SF-based scaffolds, high-precision techniques such as micro-patterning and bio-printing have been explored in recent years. These processes contribute to the diversity of surface area, mean pore size, porosity, and mechanical properties of different silk fibroin scaffolds and can be used in various TE applications to provide appropriate morphological and mechanical properties. This review introduces the physicochemical and mechanical properties of SF and looks into a range of SF-based scaffolds that have recently been developed. The typical applications of SF-based scaffolds for TE of bone, cartilage, teeth and mandible tissue, cartilage, skeletal muscle, and vascular tissue are highlighted and discussed followed by a discussion of issues to be addressed in future studies.     

丝素蛋白3D打印在生物医学领域中的应用

增材制造,也称为三维(3D)打印,正推动制造、工程、医学等领域的全面创新升级。3D打印技术由于能够个性化定制生物的复杂3D微结构,构建仿生的功能化活组织或人工器官,近十年来在生物医学领域中取得了长足的发展。丝素蛋白(SF)是一种来源丰富、生物可降解、力学性能优良、细胞相容性极佳的天然有机高分子,为3D打印墨水的设计提供了一种有前景的选择。然而,作为结构蛋白,单一组分的SF具有的生理功能有限,且其经过打印后的稳定性较差,限制了SF在3D打印以及生物医药领域中的进一步发展。为此,研究人员通过化学改性技术和先进3D打印技术相结合,使得改性后的SF能够更适用于3D打印,并发展成为一种具有应用价值的生物材料。本文综述了SF的结构特征、SF的化学修饰策略、打印墨水的制备策略以及3D打印SF材料在生物医学领域的最新应用进展,并展望了3D打印SF生物材料的未来发展趋势,为其在更广阔领域的应用提供一定的借鉴。     

Exosomes as New Generation Vehicles for Drug Delivery: Biomedical Applications and Future Perspectives

Currently, particular interest among the scientific community is focused on exploring the use of exosomes for several pharmaceutical and biomedical applications. This is due to the identification of the role of exosomes as an excellent intercellular communicator by delivering the requisite cargo comprising of functional proteins, metabolites and nucleic acids. Exosomes are the smallest extracellular vesicles (EV) with sizes ranging from 30–100 nm and are derived from endosomes. Exosomes have similar surface morphology to cells and act as a signal transduction channel between cells. They encompass different biomolecules, such as proteins, nucleic acids and lipids, thus rendering them naturally as an attractive drug delivery vehicle. Like the other advanced drug delivery systems, such as polymeric nanoparticles and liposomes to encapsulate drug substances, exosomes also gained much attention in enhancing therapeutic activity. Exosomes present many advantages, such as compatibility with living tissues, low toxicity, extended blood circulation, capability to pass contents from one cell to another, non-immunogenic and special targeting of various cells, making them an excellent therapeutic carrier. Exosome-based molecules for drug delivery are still in the early stages of research and clinical trials. The problems and clinical transition issues related to exosome-based drugs need to be overcome using advanced tools for better understanding and systemic evaluation of exosomes. In this current review, we summarize the most up-to-date knowledge about the complex biological journey of exosomes from biogenesis and secretion, isolation techniques, characterization, loading methods, pharmaceutical and therapeutic applications, challenges and future perspectives of exosomes.     

Vascularization in Bone Tissue Engineering: Physiology,Current Strategies,Major Hurdles and Future Challenges

The lack of a functional vascular supply has, to a large extent, hampered the whole range of clinical applications of ‘successful’ laboratory‐based bone tissue engineering strategies. To the present, grafts have been dependent on post‐implant vascularization, which jeopardizes graft integration and often leads to its failure. For this reason, the development of strategies that could effectively induce the establishment of a microcirculation in the engineered constructs has become a major goal for the tissue engineering research community. This review addresses the role and importance of the development of a vascular network in bone tissue engineering and provides an overview of the most up to date research efforts to develop such a network.

     

Poly (Ethyl Methacrylate) (PEMA) and its Composites for Various Applications: Background,Recent Progress,and Future challenges

This overview looks critically at the present prospects and future challenges in development of polyethyl methacrylate (PEMA) and its composites. It is shown herein to be a promising candidate for various applications, including energy storage, textile, electronics, biomedical, packaging, coatings and adhesives, etc. Due to its high ionic conductivity, thermal stability, and low cost of synthesis, PEMA is also used as a solid electrolyte in supercapacitors. This polymer has the ability to transport ions efficiently between the two electrodes of the supercapacitor, thereby leading to improved performance and efficiency. Additionally, PEMA can withstand high temperatures without breaking down, thus making it suitable for a range of applications. Further, it is shown due to its unique properties and versatility, PEMA has significant potential for a range of biomedical applications. This review of existing literature strongly suggests that the use of PEMA as a solid electrolyte in supercapacitors can be of significant potential for advancing energy storage technology. It also warrants further research to optimize its use in many other challenging practical applications.