Silk Fibroin-Based Biomaterials for Hemostatic Applications

The Emerging Role of Silk Fibroin for the Development of Novel Drug Delivery Systems

In order to reduce the toxicological impact on healthy cells and to improve the therapeutic response, many drug delivery systems have been fabricated and analysed, involving the use of different natural and synthetic materials at macro-, micro- and nanoscales. Among the natural materials which have demonstrated a huge potential for the development of effective drug delivery systems, silk fibroin has emerged for its excellent biological properties and for the possibility to be processed in a wide range of forms, which can be compliant with multiple active molecules and pharmaceutical ingredients for the treatment of various diseases. This review aims at presenting silk fibroin as an interesting biopolymer for applications in drug delivery systems, exploring the results obtained in recent works in terms of technological progress and effectiveness in vitro and in vivo.

Polydopamine-Coated Silk Fiber with Controllable Length for Enhanced Hemostatic Application

The development of highly effective hemostatic materials with high biocompatibility and outstanding performance is vital to the field of biomaterials. In this study, we develop a hemostatic fiber material that exhibits high biocompatibility and excellent performance. By incorporating polydopamine (PDA) into the alkaline treatment of silk fibroin (SF), we achieve PDA-coated SF fibers with lengths that can be controlled by the alkaline concentration. The PDA coating significantly enhances the hemostatic ability of the silk fibers and exhibits superior performance in both in vitro and ex vivo experiments. By performing animal studies involving a mouse liver puncture model and a femoral vein incision model, we demonstrate the remarkable hemostatic capability of the PDA-coated SF fibers, as evidenced by the lower blood loss compared to that of a commercial hemostat powder. These findings highlight the potential of applying a PDA-assisted alkaline treatment to SF fibers to efficiently create hemostatic fibers with controllable lengths, which would be promising candidates for clinical hemostatic applications.

A sodium alginate - silk fibroin biosponge loaded with thrombin: Effective hemostasis and wound healing

In trauma first aid, rapid hemostasis is a priority, extricating patients from hemorrhagic shock and infection risks. This paper explores novel hemostatic materials, using ion-crosslinking and freeze-drying techniques. Iterative experiments determined optimal conditions for the temperature-variable mixing-freeze-drying chemical reaction of sodium alginate (SA)/silk fibroin (SF). We used SA, SA/SF, SA/SF-TB and commercial hemostatic sponge control samples to perform hemostasis experiments on rat liver injury and femoral artery injury models, and to perform wound healing experiments on rat back full-layer skin. The results showed that the hemostatic time and blood loss of SA/SF-TB group rats (liver hemorrhage model: 397.17 ± 34.80 mg, 77.83 ± 7.41 s; Femoral artery bleeding model: 940.33 ± 41.93 mg, 96.83 ± 4.07 s) was significantly better than other experimental groups, and similar to the commercial group. The wound healing experiment showed that the new granulation tissue thickness of SA/SF-TB group was thicker (380.39 ± 28.56 μm) at day 14. In addition, the material properties and biocompatibility of sponges were characterized by cell experiments and in vivo embedding experiments. All the results showed that the SA/SF-TB hemostatic sponge prepared in this study could not only seal the wound quickly and stop bleeding, but also promote the growth of epidermal cells and fibroblasts and accelerate wound healing. This new material solves the shortcomings of traditional materials such as low stability, limited shelf life, high unit price, and has good biocompatibility, easy preparation, rapid hemostasis and other excellent properties. Therefore, this innovative hemostatic material has great prospects and potential in clinical applications.

Recent research advances on polysaccharide-, peptide-, and protein-based hemostatic materials: A review

Hemorrhage is a potentially life-threatening emergency that can occur at any time or place. Whether traumatic, congenital, surgical, disease-related, or drug-induced, bleeding can lead to severe complications or death. Therefore, the development of efficient hemostatic materials is critical. However, the results and prognosis demonstrated by clinical means of hemostasis do not reach expectations. With the development of technology, novel hemostatic materials have been developed from polysaccharides (chitosan, hyaluronic acid, alginate, cellulose, cyclodextrins, starch, dextran, and carrageenan), peptides (self-assembling peptides), and proteins (silk fibroin, collagen, gelatin, keratin, and thrombin). These new materials exhibit high hemostatic efficacy due to the enhancement or interaction of various hemostatic mechanisms. The main forms include adhesives, sealants, bandages, hemostatic powders, and hemostatic sponges. This article introduces the clotting process and principles of hemostatic methods and reviews the research on polysaccharide-, peptide-, and protein-based hemostatic materials in the last five years. The design ideas and hemostatic principles of polysaccharide-, peptide-, and protein-based hemostatic materials are mainly introduced. Finally, we summarize material designs, advantages, disadvantages, and challenges regarding hemostatic materials.

A mussel inspired polyvinyl alcohol/collagen/tannic acid bioadhesive for wet adhesion and hemostasis

Bioadhesives are useful in surgery for hemostasis, tissue sealing and wound healing. However, most bioadhesives have limitations such as weak adhesion in wet conditions, insufficient sealing and poor clotting performance. Inspired by the adhesion mechanism of marine mussels, a novel bioadhesive (PCT) was developed by simply combining polyvinyl alcohol (PVA), collagen (COL) and tannic acid (TA) together. The results showed that the adhesion, sealing and blood coagulation properties boosted with the increase of tannic acid content in PCT. The wet shear adhesion strength of PCT-5 (the weight ratio of PVA:COL:TA=1:1:5) was 60.8 ± 0.6 kPa, the burst pressure was 213.7 ± 0.7 mmHg, and the blood clotting index was 39.3% ± 0.6%, respectively. In rat heart hemostasis tests, PCT-5 stopped bleeding in 23.7 ± 3.2 s and reduced bleeding loss to 83.0 ± 19.1 mg, which outperformed the benchmarks of commercial gauze (53.3 ± 8.7 s and 483.0 ± 15.0 mg) and 3 M adhesive (Type No.1469SB, 35.3 ± 5.0 s and 264.0 ± 14.2 mg). The as-prepared bioadhesive could provide significant benefits for tissue sealing and hemorrhage control along its low cost and facile preparation process.

Preparation and application of hemostatic microspheres containing biological macromolecules and others

Bleeding from uncontrollable wounds can be fatal, and the body's clotting mechanisms are unable to control bleeding in a timely and effective manner in emergencies such as battlefields and traffic accidents. For irregular and inaccessible wounds, hemostatic materials are needed to intervene to stop bleeding. Hemostatic microspheres are promising for hemostasis, as their unique structural features can promote coagulation. There is a wide choice of materials for the preparation of microspheres, and the modification of natural macromolecular materials such as chitosan to enhance the hemostatic properties and make up for the deficiencies of synthetic macromolecular materials makes the hemostatic microspheres multifunctional and expands the application fields of hemostatic microspheres. Here, we focus on the hemostatic mechanism of different materials and the preparation methods of microspheres, and introduce the modification methods, related properties and applications (in cancer therapy) for the structural characteristics of hemostatic microspheres. Finally, we discuss the future trends of hemostatic microspheres and research opportunities for developing the next generation of hemostatic microsphere materials.

Silk fibroin-derived electrospun materials for biomedical applications: A review

Electrospinning is a versatile technique for fabricating polymeric fibers with diameters ranging from micro- to nanoscale, exhibiting multiple morphologies and arrangements. By combining silk fibroin (SF) with synthetic and/or natural polymers, electrospun materials with outstanding biological, chemical, electrical, physical, mechanical, and optical properties can be achieved, fulfilling the evolving biomedical demands. This review highlights the remarkable versatility of SF-derived electrospun materials, specifically focusing on their application in tissue regeneration (including cartilage, cornea, nerves, blood vessels, bones, and skin), disease treatment (such as cancer and diabetes), and the development of controlled drug delivery systems. Additionally, we explore the potential future trends in utilizing these nanofibrous materials for creating intelligent biomaterials, incorporating biosensors and wearable sensors for monitoring human health, and also discuss the bottlenecks for its widespread use. This comprehensive overview illuminates the significant impact and exciting prospects of SF-derived electrospun materials in advancing biomedical research and applications.

Chemical modification of chitosan for developing of new hemostatic materials: A review

Uncontrolled bleeding that occurs during surgery, trauma, and in combat conditions is critical and require immediate action. Chitosan is a polysaccharide, obtained from natural sources with unique biological properties. It is often used as basis for local hemostatic agents (LHA). We summarized the data on hemostatic properties of chitosan, commercially available chitosan-based products with focus in the field of chemical modification of chitosan. Various approaches are used to enhance hemostatic activity of chitosan-based materials. The approach with chemical modification of chitosan allows changing the properties of the polymer in order to obtain an active macromolecule that contributes to hemostasis. Ongoing research on the mechanism of interaction with blood components in the case of different chitosan derivatives will make it possible to identify promising directions for chemical modification to obtain an effective LHA.

The emerging progress on wound dressings and their application in clinic wound management

BACKGROUND

In addition to its barrier function, the skin plays a crucial role in maintaining the stability of the body's internal environment and normal physiological functions. When the skin is damaged, it is important to select proper dressings as temporary barriers to cover the wound, which can exert significant effects on defence against microbial infection, maintaining normal tissue/cell functions, and coordinating the process of wound repair and regeneration. It now forms an important approach in clinic practice to facilitate wound repair.

SEARCH STRATEGIES

We conducted a comprehensive literature search using online databases including PubMed, Web of Science, MEDLINE, ScienceDirect, Wiley Online Library, CNKI, and Wanfang Data. In addition, information was obtained from local and foreign books on biomaterials science and traumatology.

RESULTS

This review focuses on the efficacy and principles of functional dressings for anti-bacteria, anti-infection, anti-inflammation, anti-oxidation, hemostasis, and wound healing facilitation; and analyses the research progress of dressings carrying living cells such as fibroblasts, keratinocytes, skin appendage cells, and stem cells from different origins. We also summarize the recent advances in intelligent wound dressings with respect to real-time monitoring, automatic drug delivery, and precise adjustment according to the actual wound microenvironment. In addition, this review explores and compares the characteristics, advantages and disadvantages, mechanisms of actions, and application scopes of dressings made from different materials.

CONCLUSION

The real-time and dynamic acquisition and analysis of wound conditions are crucial for wound management and prognostic evaluation. Therefore, the development of modern dressings that integrate multiple functions, have high similarity to the skin, and are highly intelligent will be the focus of future research, which could drive efficient wound management and personalized medicine, and ultimately facilitate the translation of health monitoring into clinical practice.

Evaluation and Application of Silk Fibroin Based Biomaterials to Promote Cartilage Regeneration in Osteoarthritis Therapy

Osteoarthritis (OA) is a common joint disease characterized by cartilage damage and degeneration. Traditional treatments such as NSAIDs and joint replacement surgery only relieve pain and do not achieve complete cartilage regeneration. Silk fibroin (SF) biomaterials are novel materials that have been widely studied and applied to cartilage regeneration. By mimicking the fibrous structure and biological activity of collagen, SF biomaterials can promote the proliferation and differentiation of chondrocytes and contribute to the formation of new cartilage tissue. In addition, SF biomaterials have good biocompatibility and biodegradability and can be gradually absorbed and metabolized by the human body. Studies in recent years have shown that SF biomaterials have great potential in treating OA and show good clinical efficacy. Therefore, SF biomaterials are expected to be an effective treatment option for promoting cartilage regeneration and repair in patients with OA. This article provides an overview of the biological characteristics of SF, its role in bone and cartilage injuries, and its prospects in clinical applications to provide new perspectives and references for the field of bone and cartilage repair.

An All-In-One Transient Theranostic Platform for Intelligent Management of Hemorrhage

Developing theranostic devices to detect bleeding and effectively control hemorrhage in the prehospital setting is an unmet medical need. Herein, an all-in-one theranostic platform is presented, which is constructed by sandwiching silk fibroin (SF) between two silver nanowire (AgNW) based conductive electrodes to non-enzymatically diagnose local bleeding and stop the hemorrhage at the wound site. Taking advantage of the hemostatic property of natural SF, the device is composed of a shape-memory SF sponge, facilitating blood clotting, with ≈82% reduction in hemostatic time in vitro as compared with untreated blood. Furthermore, this sandwiched platform serves as a capacitive sensor that can detect bleeding and differentiate between blood and other body fluids (i.e., serum and water) via capacitance change. In addition, the AgNW electrode endows anti-infection efficiency against Escherichia coli and Staphylococcus aureus. Also, the device shows excellent biocompatibility and gradually biodegrades in vivo with no major local or systemic inflammatory responses. More importantly, the theranostic platform presents considerable hemostatic efficacy comparable with a commercial hemostat, Dengen, in rat liver bleeding models. The theranostic platform provides an unexplored strategy for the intelligent management of hemorrhage, with the potential to significantly improve patients' well-being through the integration of diagnostic and therapeutic capabilities.

Sustainable Antibacterial Surgical Suture Based on Recycled Silk Resource by an Internal Combination of Inorganic Nanomaterials

The current antibacterial treatment methods of silk sutures can only be finished by surface modification, leading to problems of short antibacterial effects, easy slow-release consumption, prominent toxicity, and susceptibility to drug resistance. Speculatively, surgical sutures combining antibacterial material internally will possess a more promising efficacy. Hence, we extracted recycled regenerated silk fibroin (RRSF) from waste silk resources to make RRSF solutions. Internally combining with inorganic titanium dioxide (TiO₂) nanoparticles, we fabricated antibacterial RRSF-based surgical sutures. The morphologies, mechanical and antibacterial properties, biocompatibility tests, and in vivo experiments were carried out. The results showed that the surgical sutures with 1.25 wt % TiO₂ acquired 2.40 N knot strength (143 μm diameter) and achieved a sustainable antibacterial effect of 93.58%. Surprisingly, the sutures significantly reduced inflammatory reactions and promoted wound healing. Surgical sutures in this paper realize high-value recovery of waste silk fibers and provide a novel approach to preparing multifunctional sutures.

High Performance Marine and Terrestrial Bioadhesives and the Biomedical Applications They Have Inspired

This study has reviewed the naturally occurring bioadhesives produced in marine and freshwater aqueous environments and in the mucinous exudates of some terrestrial animals which have remarkable properties providing adhesion under difficult environmental conditions. These bioadhesives have inspired the development of medical bioadhesives with impressive properties that provide an effective alternative to suturing surgical wounds improving closure and healing of wounds in technically demanding tissues such as the heart, lung and soft tissues like the brain and intestinal mucosa. The Gecko has developed a dry-adhesive system of exceptional performance and has inspired the development of new generation re-usable tapes applicable to many medical procedures. The silk of spider webs has been equally inspiring to structural engineers and materials scientists and has revealed innovative properties which have led to new generation technologies in photonics, phononics and micro-electronics in the development of wearable biosensors. Man made products designed to emulate the performance of these natural bioadhesive molecules are improving wound closure and healing of problematic lesions such as diabetic foot ulcers which are notoriously painful and have also found application in many other areas in biomedicine. Armed with information on the mechanistic properties of these impressive biomolecules major advances are expected in biomedicine, micro-electronics, photonics, materials science, artificial intelligence and robotics technology.

Three-Dimensional Digital Light-Processing Bioprinting Using Silk Fibroin-Based Bio-Ink: Recent Advancements in Biomedical Applications

Three-dimensional (3D) bioprinting has been developed as a viable method for fabricating functional tissues and organs by precisely spatially arranging biomaterials, cells, and biochemical components in a layer-by-layer fashion. Among the various bioprinting strategies, digital light-processing (DLP) printing has gained enormous attention due to its applications in tissue engineering and biomedical fields. It allows for high spatial resolution and the rapid printing of complex structures. Although bio-ink is a critical aspect of 3D bioprinting, only a few bio-inks have been used for DLP bioprinting in contrast to the number of bio-inks employed for other bioprinters. Recently, silk fibroin (SF), as a natural bio-ink material used for DLP 3D bioprinting, has gained extensive attention with respect to biomedical applications due to its biocompatibility and mechanical properties. This review introduces DLP-based 3D bioprinting, its related technology, and the fabrication process of silk fibroin-based bio-ink. Then, we summarize the applications of DLP 3D bioprinting based on SF-based bio-ink in the tissue engineering and biomedical fields. We also discuss the current limitations and future perspectives of DLP 3D bioprinting using SF-based bio-ink.

Design of biopolymer-based hemostatic material: Starting from molecular structures and forms

Uncontrolled bleeding remains as a leading cause of death in surgical, traumatic, and emergency situations. Management of the hemorrhage and development of hemostatic materials are paramount for patient survival. Owing to their inherent biocompatibility, biodegradability and bioactivity, biopolymers such as polysaccharides and polypeptides have been extensively researched and become a focus for the development of next-generation hemostatic materials. The construction of novel hemostatic materials requires in-depth understanding of the physiological hemostatic process, fundamental hemostatic mechanisms, and the effects of material chemistry/physics. Herein, we have recapitulated the common hemostatic strategies and development status of biopolymer-based hemostatic materials. Furthermore, the hemostatic mechanisms of various molecular structures (components and chemical modifications) are summarized from a microscopic perspective, and the design based on them are introduced. From a macroscopic perspective, the design of various forms of hemostatic materials, e.g., powder, sponge, hydrogel and gauze, is summarized and compared, which may provide an enlightenment for the optimization of hemostat design. It has also highlighted current challenges to the development of biopolymer-based hemostatic materials and proposed future directions in chemistry design, advanced form and clinical application.

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Biopolymers possess sound biocompatibility, biodegradability and bioactivity for the design of hemostatic materials.

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Molecular structure designs including component and chemical modification are summarized from a microscopic perspective.

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Design of various forms of hemostatic materials is discussed and compared synthetically from a macroscopic perspective.