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Background: Autologous tissues such as buccal mucosa (BM) are widely used for reconstruction of urethral strictures; however, limitations such as donor site morbidity and scarce tissue supply require the development of alternative biomaterials for urethral repair. The goals of this study were to determine the safety and efficacy of bi-layer silk fibroin (BLSF) matrices for urethral stricture repair and compare histological and functional outcomes to the standard approach, BM urethroplasty under good laboratory practices.Material and methods: A total of 13 rabbits exhibiting urethral stricture formation following electrocoagulation injury were treated with onlay urethroplasty with either acellular BLSF (N = 7) or autologous BM (N = 6) grafts for 3 months. Uninjured control rabbits were maintained in parallel (N = 4).Results and conclusion: Animals receiving BLSF implants were demonstrated to be functionally equivalent to BM grafts in their ability to restored strictured calibers, support micturition and promote tissue regeneration with minimal inflammation.

BackgroundAutologous tissues derived from bowel, buccal mucosa and skin are primarily used to repair or replace diseased vaginal segments as well as create neovaginas for male-to-female transgenders. These grafts are often limited by scarce tissue supply, donor site morbidity and post-operative complications. Bi-layer silk fibroin (BLSF) biomaterials represent potential alternatives for vaginoplasty given their structural strength and elasticity, low immunogenicity, and processing flexibility. The goals of the current study were to assess the potential of acellular BLSF scaffolds for vaginal tissue regeneration in respect to conventional small intestinal submucosal (SIS) matrices in a rat model of vaginoplasty.MethodsInlay vaginoplasty was performed with BLSF and SIS scaffolds (N = 21 per graft) in adult female rats for up to 2 months of implantation. Nonsurgical controls (N = 4) were investigated in parallel. Outcome analyses included histologic, immunohistochemical and histomorphometric evaluations of wound healing patterns; µ-computed tomography (CT) of vaginal continuity; and breeding assessments.ResultsAnimals in both scaffold cohorts exhibited 100% survival rates with no severe post-operative complications. At 2 months post-op, µ-CT analysis revealed normal vaginal anatomy and continuity in both graft groups similar to controls. In parallel, BLSF and SIS grafts also induced comparable constructive remodeling patterns and were histologically equivalent in their ability to support formation of vascularized vaginal neotissues with native tissue architecture, however with significantly less smooth muscle content. Vaginal tissues reconstructed with both implants were capable of supporting copulation, pregnancy and similar amounts of live births.ConclusionsBLSF biomaterials represent potential "off-the-shelf" candidates for vaginoplasty.

The frequent occurrence of respiratory infectious diseases has made it difficult for traditional antibacterial materials to meet practical needs in recent years. There was an urgent need to develop new antimicrobial materials with stronger antimicrobial effects and biosafety. In this paper, the carboxymethyl chitosan (CMCTS)/silk fibroin (SF) composite microspheres were synthesized through self‐assembly, and the Ag+/CMCTS/SF composite microspheres were prepared by loading the Ag+ onto their surface. It investigated the effect of CMCTS contents, SF on the size and secondary structure of CMCTS/SF composite microspheres, and the antibacterial activity and mechanism of Ag+/CMCTS/SF composite microspheres. The results showed that the average particle size distribution size of CMCTS/SF composite microspheres was ranged from approximately 593–1115 nm. When CMCTS was added at 50 wt%, the content of β‐sheet structures in silk fibroin microspheres was the largest at 38.6%. And the CMCTS/SF composite microspheres loaded with Ag+ enhanced the bactericidal rate against Escherichia coli and Staphylococcus aureus by 27.51% and 36.39%, respectively. In addition, the Ag+/CMCTS/SF composite microspheres have high biological safety, providing a new method for designing an efficient, green, and safe composite antibacterial agent. [ABSTRACT FROM AUTHOR]

Dental caries result from an imbalance between the demineralization and remineralization of dental hard tissues, primarily caused by biofilm accumulation. According to the theory of interrupting dental caries, effective anticaries materials and techniques should possess both remineralizing and antibacterial properties. However, current anticaries materials fail to mimic the process of amelogenesis to achieve remineralization while inhibiting the adhesion of cariogenic bacteria and the formation of biofilms. In this study, silk fibroin (SF) loaded with benzalkonium chloride (BZC) successfully formed an SF-BZC composite. This composite stabilized amorphous calcium phosphate (ACP), creating an ACP@SF-BZC dual-functional nanocomplex with both remineralizing and antibacterial properties. ACP@SF-BZC demonstrated significant anti-adhesion and biofilm inhibitory effects against Streptococcus mutans and Streptococcus sobrinus. Moreover, compared to fluoride, ACP@SF-BZC significantly enhanced the remineralization of demineralized enamel surfaces, forming a stable remineralized layer with improved mechanical properties, both in vitro and in vivo. In summary, the dual-function ACP@SF-BZC nanocomplex, with its remineralizing and antibacterial effects, offers a promising alternative for preventing and arresting enamel caries. [Display omitted] • Construction of A Novel Bifunctional Nanocomplex-ACP@SF-BZC. • Biomimetic Amelogenisis Process in Vitro. • Potential for Clinical Application in Enamel Caries Management. [ABSTRACT FROM AUTHOR]

In this research, a novel hydrogel nanobiocomposite was developed by combining natural Collagen (Col) and Gelatin (Ge) biopolymers with Glutaraldehyde (GA), forming a cross-linked Col-Ge hydrogel. This hydrogel was further enhanced by adding Silk fibroin (SF) protein and ZnFe layered double hydroxide (LDH) for improved mechanical properties and antibacterial functionality. Various analytical techniques were employed to comprehensively characterize the structural features of the designed Col-Ge hydrogel/SF/ZnFe LDH nanocomposite. Biological tests, including MTT and hemolytic assays, demonstrated 95.25 % and 96.51 % cell viability for human skin fibroblast cells (Hu02) after 2 and 3 days. Also, in addition to non-toxicity, the fibroblast shape of Hu02 cells was entirely maintained. The nanocomposite exhibited only 4.83 %hemolytic activity on human RBCs, indicating excellent hemocompatibility. In inhibiting bacterial growth, it showed 27.51 % inhibition for E. coli and 16.8 % for S. aureus. These findings suggest that the Col-Ge hydrogel/SF/ZnFe LDH nanobiocomposite holds promise for biomedical applications. [Display omitted] • Collagen-Gelatin hydrogel as a biocompatible and main substrate was prepared. • Silk fibroin was added due to increase mechanical properties and biocompatibility. • Antibacterial activity was achieved because of adding ZnFe LDH. • This nanostructure has low cytotoxicity and high biocompatibility. • Cell viability against treated Hu02 cells after 72 h was 96.15 %. [ABSTRACT FROM AUTHOR]

The conventional treatment of osteomyelitis with antibiotic‐loaded nondegradable polymethylmethacrylate (ATB‐PMMA) beads has certain limitations, including impeded bone reconstruction and the need for secondary surgery. To overcome this challenge, this study aimed to develop and characterize an injectable vancomycin‐loaded silk fibroin/methylcellulose containing calcium phosphate‐based in situ thermosensitive hydrogel (VC‐SF/MC‐CAPs). The VC‐SF/MC‐CAPs solution can be easily administered at room temperature with a low injectability force of ≤30 N and a high vancomycin (VC) content of ~96%. Additionally, at physiological temperature (37 °C), the solution could transform into a rigid hydrogel within 7 minutes. In vitro drug release performed under both physiological (pH 7.4) and infection conditions (pH 4.5) revealed a prolonged release pattern of VC‐SF/MC‐CAPs following the Peppas–Sahlin kinetic model. In addition, the released VC from VC‐SF/MC‐CAPs hydrogels exhibited antibacterial activity against Staphylococcus aureus for a period exceeding 35 days, as characterized by the disk diffusion assay. Furthermore, at pH 7.4, the VC‐SF/MC‐CAPs demonstrated >60% degradation within 35 days. Importantly, when exposed to physiological pH conditions, CAPs are transformed into bioactive hydroxyapatite, which benefits bone formation. Therefore, VC‐SF/MC‐CAPs showed significant potential as a local drug delivery system for treating osteomyelitis. [ABSTRACT FROM AUTHOR]

Water-stable proteins may offer a new field of applications in smart materials for buildings and infrastructures where hydraulic reactions are involved. In this study, cement mortars modified through water-soluble silk fibroin (SF) are proposed. Water-soluble SF obtained by redissolving SF films in phosphate buffer solution (PBS) showed the formation of a gel with the β sheet features of silk II. Electrical measurements of SF indicate that calcium ions are primarily involved in the conductivity mechanism. By exploiting the water solubility properties of silk II and Ca2+ ion transport phenomena as well as their trapping effect on water molecules, SF provides piezoresistive and piezocapacitive properties to cement mortars, thus enabling self-sensing of mechanical strain, which is quite attractive in structural health monitoring applications. The SF/cement-based composite introduces a capacitive gauge factor which surpasses the traditional resistive gauge factor reported in the literature by threefold. Cyclic voltammetry measurements demonstrated that the SF/cement mortars possessed memcapacitive behavior for positive potentials near +5 V, which was attributed to an interfacial charge build-up modulated by the SF concentration and the working electrode. Electrical square-biphasic excitation combined with cyclic compressive loads revealed memristive behavior during the unloading stages. These findings, along with the availability and sustainability of SF, pave the way for the design of novel multifunctional materials, particularly for applications in masonry and concrete structures. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is an ideal material for microneedle (MN) preparation. However, long extraction and short storage durations limit its application. Furthermore, MNs prepared from SF alone are easy to break during skin insertion. In this study, a regenerated SF solution was autoclaved and freeze-dried to produce a stable and water-soluble SF sponge. The freeze-dried SF (FD-SF) solution was ultrasonically treated before being used in the fabrication of MNs. The ultrasonically modified SFMNs (US-SFMNs) were evaluated in comparison to FD-SFMNs made from FD-SF and conventional SFMNs made from regenerated SF. The results indicated that the FD-SF could be completely dissolved in water and remained stable even after 8 months of storage. FTIR and XRD analyses showed that SF in US-SFMNs had increased β-sheet content and crystallization compared to FD-SFMNs, by 7.3% and 8.1%, respectively. The US-SFMNs had higher mechanical strength than conventional SFMNs and FD-SFMNs, with a fracture force of 1.55 N per needle and a rat skin insertion depth of 370 μm. The US-SFMNs also demonstrated enhanced transdermal drug delivery and enzymatic degradation in vitro. In conclusion, the autoclaving and freeze drying of SF, as well as ultrasonication-induced MN preparation, provide promising SF-based microneedles for transdermal drug delivery. [ABSTRACT FROM AUTHOR]

[Display omitted] With the rapid development of the global economy and the continuous consumption of fossil resources, sustainable and biodegradable natural biomass has garnered extensive attention as a promising substitute for synthetic polymers. Due to their hierarchical and nanoscale structures, natural biopolymers exhibit remarkable mechanical properties, along with excellent innate biocompatibility and biodegradability, demonstrating significant potential in various application scenarios. Among these biopolymers, proteins and polysaccharides are the most commonly studied due to their low cost, abundance, and ease of use. However, the direct processing/conversion of proteins and polysaccharides into their final products has been a long-standing challenge due to their natural morphology and compositions. In this review, we emphasize the importance of processing natural biopolymers into high-value-added products through sustainable and cost-effective methods. We begin with the extraction of four types of natural biopolymers: cellulose, chitosan, eggshell membrane, and silk fibroin. The processing and post-functionalization strategies for these natural biopolymers are then highlighted. Alongside their unique structures, the versatile potential applications of these processable natural biopolymers in biomedical engineering, biosensors, environmental engineering, and energy applications are illustrated. Finally, we provide a summary and future outlook on processable natural biopolymers, underscoring the significance of converting natural biopolymers into valuable biomaterial platforms. [ABSTRACT FROM AUTHOR]

Liquid-liquid phase separation (LLPS) of proteins can be considered an intermediate solubility regime between disperse solutions and solid fibers. While LLPS has been described for several pathogenic amyloids, recent evidence suggests that it is similarly relevant for functional amyloids. Here, we review the evidence that links spider silk proteins (spidroins) and LLPS and its role in the spinning process. Major ampullate spidroins undergo LLPS mediated by stickers and spacers in their repeat regions. During spinning, the spidroins droplets shift from liquid to crystalline states. Shear force, altered ion composition, and pH changes cause micelle-like spidroin assemblies to form an increasingly ordered liquid-crystalline phase. Interactions between polyalanine regions in the repeat regions ultimately yield the characteristic β-crystalline structure of mature dragline silk fibers. Based on these findings, we hypothesize that liquid-liquid crystalline phase separation (LLCPS) can describe the molecular and macroscopic features of the phase transitions of major ampullate spidroins during spinning and speculate whether other silk types may use a similar mechanism to convert from liquid dope to solid fiber. Liquid-liquid phase separation (LLPS) of proteins can be considered an intermediate solubility regime between disperse solutions and solid fibers, relevant to both pathogenic and functional amyloids. Here, the authors review the evidence that links spider silk proteins (spidroins) and LLPS and its role in the spinning process. [ABSTRACT FROM AUTHOR]

Hydrogel‐based wearable strain sensors have recently gained considerable interest due to their promising applications in real‐time health monitoring and motion detection. However, achieving integrated high‐stretchability, self‐adhesiveness, and long‐term water‐retaining property simultaneously in hydrogel systems remains a big challenge, which limits their applications in wearable electronics. Herein, a multifunctional hydrogel material designed is proposed for wearable strain sensors that can be manufactured by digital light processing (DLP) 3D printing technology. By tailoring the composition of chemically cross‐linked networks (ploy(acrylamide)/poly(acrylic acid)/poly(ethylene glycol) diacrylate), physically cross‐linked networks (ploy(acrylamide)/poly(acrylic acid)/poly(ethylene glycol) diacrylate/silk fibroin/glycerol/water) and microstructures on the surface, the 3D printed hydrogel exhibits promising superior and adjustable mechanical properties, tunable adhesion and good water‐retaining property simultaneously. In addition, through adding conductive ions, high ionic conductivity can also be achieved for stretchable sensing applications. Based on these integrated multifunctionalities, the 3D printed hydrogel is suitable for wearable strain sensors to detect various body motions. This work provides a prospect for 3D printable hydrogel systems with broad applications in wearable electronics. [ABSTRACT FROM AUTHOR]

This review underscores the novelty of silk sericin, often regarded as a byproduct in silk production. Comprising approximately 30% of silk, sericin possesses valuable properties that have been largely overlooked in favor of silk fibroin. This work focuses on innovative extraction methods to convert sericin, typically considered waste, into a valuable resource. By examining these extraction techniques alongside diverse applications, the review aims to enhance the recognition and utilization of silk sericin in research and industry. Various extraction processes where the traditional methods, and some new techniques, are all discussed. In detail, the advantages, limitations, and strategy optimization associated with each extraction method are highlighted. For instance, silk sericin has shown promise as a wound treatment agent, a scaffold for tissue engineering, a carrier for drug delivery, and a biomaterial for regenerative medicine in the field of biomedical science due to its biocompatibility, biodegradability, and nontoxicity. Additionally, it also finds application in the cosmetic industry, where it is used in skincare products due to its moisturizing, antioxidant, and antiaging properties. Eventually, the challenges, limitations, and prospects of silk sericin are intensively discussed. This comprehensive review is expected to serve the growing body of knowledge surrounding silk sericin and foster further research and development of silk sericin‐related fields. [ABSTRACT FROM AUTHOR]

Developing dressing for wound dressings represents a significant challenge for the scientific community. In this study, a conductive hydrogel was synthesized to promote the wound‐healing process. This hydrogel is composed of silk fibroin (SF), reduced graphene oxide (rGO), and glycerol (G). The impact of modifying the SF:rGO ratio, and the G content (%), on the physicochemical and biological properties. The hydrogels were characterized using FT‐IR, SEM, XRD, TGA, swelling, mechanical resistance, and conductivity. The cytotoxicity of the materials and their wound‐healing capacity in human fibroblasts were also determined. Chemical analysis revealed that the gelation of SF occurs due to the formation of β sheet structures, which was confirmed by the shift from amide I to amide II. An Increase in the SF:rGO ratio favored swelling behavior, although increasing G reduced this effect. The swelling of the hydrogel followed a Fick diffusion mechanism. Furthermore, the increase in the SF:rGO ratio and the percentage G improved the conductivity of the materials. The hydrogels were found to be non‐cytotoxic to human fibroblasts, and those containing rGO exhibited superior wound healing capacity compared to the positive control cell culture medium. Therefore, SF:rGO hydrogels could be considered promising candidates for wound dressing. [ABSTRACT FROM AUTHOR]

The risk of infections in chronic wounds represents a serious issue, particularly in aged people and in patients affected by diseases such as diabetes and obesity. Moreover, the growing resistance demonstrated by many bacterial strains has significantly reduced the therapeutic options for clinicians and has become a great challenge for the researchers in the definition of novel approaches that promote the wound healing process and reduce the healing time. Tissue engineering approaches based on biomaterials and three-dimensional scaffolds have demonstrated huge potential in supporting cell proliferation; among them, Bombyx mori-derived silk fibroin is a very appealing possibility for the development of devices with regenerative properties for wound healing applications. However, due to the high risk of infections in chronic wounds, an antibacterial treatment is also strongly encouraged for preventing bacterial proliferation at the wound site. In this work, to develop a device with regenerative and antibacterial properties, antibacterial silver coatings were deposited onto silk fibroin scaffolds, and the effect of the treatment in terms of chemical–physical and microbiological properties was investigated. The results demonstrated that the silver treatment improved the mechanical properties of the protein scaffold and provided good antibacterial efficacy against representative bacterial strains in wound infection, namely Escherichia coli and antibiotic-resistant Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

In the present study, a method is proposed for preparing novel ductile‐sticky materials that can be used as bone void fillers using hydrolyzed wool‐keratin (WK) and silk fibroin (SF). This methodology uses citric acid as a cross‐linking agent in preparing keratin paste (KP) owing to its non‐toxicity and plasticizing properties. The Keratin paste‐silk fibroin structure (KPSF) is obtained by adding SF, which possesses biocompatible and superior mechanical properties. Methanol treatment is employed on the KPSF mixture to convert the Silk I structure in the SF to Silk II, resulting in a water‐insoluble and tightly packed proteinaceous structure. The physicochemical properties of both bioscaffolds are investigated and discussed in detail by comparison. Based on the findings, the presence of SF in the KPSF structure contributed to properties such as flexibility and porosity. In ovo CAM analysis reveals that both materials exhibit proangiogenic properties and are biocompatible. KP and KPSF bioscaffolds can be converted into ductile‐sticky forms by adding water. It believes that these forms can easily apply to bone defect areas, particularly cavitary bone defects. Furthermore, KPSF bioscaffolds, with better mechanical properties, can be considered candidates for use in non‐load‐bearing bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Microparticles derived from biomaterials are becoming increasingly popular for application in drug delivery systems. In this study, the water-in-oil (W/O) emulsification–diffusion method was used to create cellulose (C), silk fibroin (SF), and C/SF composite microparticles. We then observed the morphology of all obtained microparticles using scanning electron microscopy (SEM), evaluated their functional groups using attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), and conducted thermogravimetric analysis using a thermogravimetric analyzer (TGA). SEM micrographs indicated that the native SF microparticles have the highest spherical shape with smooth surfaces. With blue dextran, the C microparticle was smaller than the native microparticle, while the drug-loaded SF microparticles were larger than the native microparticle. The morphological surfaces of the C/SF composite microparticles were varied in shape and surface depending on the C/SF ratio used. The spherical shape of the C/SF composite microparticle increased as the SF content increased. Furthermore, the size of the drug-loaded C/SF composite microparticles increased when the SF content gradually increased. The significant functional groups in the C and SF structures were identified based on the ATR-FTIR data, and a suggestion was made regarding the interaction between the functional groups of each polymer. When compared to both native polymers, the C/SF composite microparticles exhibit improved thermal stability. XRD patterns indicated that all prepared particles have crystalline structures and are directly affected by the released profile. The C/SF composite microparticle at a 1:3 ratio had the lowest drug release content, whereas the hydrophilicity of the C microparticle affected the highest drug release content. As a result, one crucial factor affecting the medication released from the microparticle is its structure stability. According to the obtained results, C, SF, and C/SF composite microparticles show promise as delivery systems for drugs with controlled release. [ABSTRACT FROM AUTHOR]

This paper investigates the dissolution of two biopolymers, cellulose and silk fibroin, in a mixture of 1-ethyl-3-methylimidazolium acetate (EmimAc) and dimethyl sulphoxide (DMSO). EmimAc is a promising environmentally friendly solvent currently in wide use but can be limited by its high viscosity, which inhibits the speed of dissolution. To mediate this, DMSO has been used as a cosolvent and has been shown to significantly lower the solution viscosity and aid mass transport. Dissolution experiments are carried out separately for both cellulose and silk fibrion with a range of EmimAc:DMSO ratios from 100 wt% EmimAc to 100 wt% DMSO. Interestingly, the optimal EmimAc:DMSO ratio (in terms of dissolution speed) is found to be very different for the two biopolymers. For cellulose, a mixture of 20 wt% EmimAc with 80 wt% DMSO is found to have the fastest dissolution speed, while for silk fibroin, a ratio of 80 wt% EmimAc with 20 wt% DMSO proves the fastest. These dissolution trials are complemented by rheological and nuclear magnetic resonance experiments to provide further insight into the underlying mechanisms. Finally, we produce hybrid biopolymer films from a solution to show how this work provides a foundation for future effective dissolution and the preparation of hybrid biopolymer films and hybrid biocomposites. [ABSTRACT FROM AUTHOR]

This study explores the efficacy of a vancomycin-loaded silk fibroin/calcium phosphate/methylcellulose-based in situ thermosensitive hydrogel (VM-SF/CaP/MC) in promoting the osteogenic differentiation of preosteoblast cells. Three VM-SF/CaP/MC formulations with varying low (L) and high (H) concentrations of silk fibroin (SF) and calcium phosphate (CaP) were prepared: VM-HSF/LCaP/MC, VM-LSF/HCaP/MC, and VM-HSF/HCaP/MC. These hydrogels significantly enhanced MC3T3-E1 cell migration and proliferation in a dose- and time-dependent manner, achieving complete cell migration within 48 h. In addition, they significantly promoted alkaline phosphatase activity, collagen content, and mineralization in MC3T3-E1 cells, indicating their potential for osteogenesis. Among the hydrogel formulations, the VM-HSF/HCaP/MC hydrogel, with high SF and CaP content, demonstrated superior potential in promoting the osteogenic differentiation of MC3T3-E1 cells. It exhibited the highest ALP activity (11.13 ± 0.91 U/mg protein) over 14 days, along with increased collagen content (54.00 ± 1.71 µg/mg protein) and mineralization (15.79 ± 1.48 mM) over 35 days. Therefore, this formulation showed a promising candidate for clinical application in localized bone regeneration, particularly in treating osteomyelitis. [ABSTRACT FROM AUTHOR]

Natural‐derived biomaterials can be used as substrates for the growth, proliferation, and differentiation of cells. In this study, bovine vitreous humor as a biological material was cross‐linked to silk fibroin with different concentration ratios to design a suitable substrate for corneal tissue regeneration. The cross‐linked samples were evaluated with different analyses such as structural, physical (optical, swelling, and degradation), mechanical, and biological (viability, cell adhesion) assays. The results showed that all samples had excellent transparency, especially those with higher silk fibroin content. Increasing the ratio of vitreous humor to silk fibroin decreased mechanical strength and increased swelling and degradation, respectively. There was no significant difference in the toxicity of the samples, and with the increase in vitreous humor ratio, adhesion and cell proliferation increased. Generally, silk fibroin with vitreous humor can provide desirable characteristics as a transparent film for corneal wound healing. [ABSTRACT FROM AUTHOR]

AbstractThis paper describes our research on a facile and effective approach to fabricate novel silk fibroin/poly(1,4-butylene succinate) (SF/PBS) composites for the first time. Scanning electron microscopy (SEM), infrared spectra (IR), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA) were used to investigate the morphology, chemical structure, crystalline state, thermostability and possible interactions of SF with PBS for the SF/PBS composites. In addition, the determinations of the EC109 cell viability was also been completed to explore the influence of SF/PBS mass ratio on cytocompatibility. Because of the composite of SF with the PBS, the thermostability and cell viability of the SF/PBS composites were higher than those of neat SF material. However, SF did not chemically react with PMMA during the formation of the composite, and SF hardly interacts with PBS in the composite. [ABSTRACT FROM AUTHOR]

The rice leaf folder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), is a major migratory pest in rice agriculture. This pest is characterised by its larvae's ability to fold rice leaves using silk, a behaviour that culminates in the formation of a silken cocoon during the pupal stage. The fibroin light chain (CmFib‐L) gene is crucial for silk production, yet its specific function in C. medinalis has reminded elusive. This study presents a comprehensive analysis of the CmFib‐L gene, revealing its complete open reading frame (ORF) and expression patterns. Notably, the gene is highly expressed in the fifth‐instar larvae and the silk gland, which are critical stages for silk production. Our experiments demonstrate that silencing the CmFib‐L gene leads to a reduction in pupal weight, an extension of the pupal stage and a disorganised silk cocoon. Furthermore, the larval behaviour of leaf folding and spinning is significantly impaired when the expression of CmFib‐L is downregulated. These findings not only show the importance of fibroin light chain in silk production but also reveal a new target gene to regulate and control the behaviour and development of C. medinalis. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks designed as chromatic sensors offer opportunities to probe biological interfaces, particularly when combined with biocompatible matrices. Particularly compelling is the prospect of chemical tomography – or the 3D spatial mapping of chemical detail within the complex environment of living systems. Herein, we demonstrate a chromic Covalent Organic Framework (COF) integrated within silk fibroin (SF) microneedles that probe plant vasculature, sense the alkalization of vascular fluid as a biomarker for drought stress, and provide a 3D in-vivo mapping of chemical gradients using smartphone technology. A series of Schiff base COFs with tunable pKa ranging from 5.6 to 7.6 enable conical, optically transparent SF microneedles with COF coatings of 120 to 950 nm to probe vascular fluid and the surrounding tissues of tobacco and tomato plants. The conical design allows for 3D mapping of the chemical environment (such as pH) at standoff distances from the plant, enabling in-vivo chemical tomography. Chromatic COF sensors of this type will enable multidimensional chemical mapping of previously inaccessible and complex environments. It is promising but elusive to use covalent organic frameworks (COFs)-based chromatic sensors for chemical tomography – or the 3D spatial mapping of chemical details within living systems. Here, the authors report a COF-silk fibroin microneedle interface capable of 3D mapping of the chemical environment at standoff distances from the plant, enabling in-vivo chemical tomography. [ABSTRACT FROM AUTHOR]

A palladium catalyst supported on silk fibroin (Pd/SF) has been tested in the Sonogashira coupling reactions of a wide range of aryl iodides and terminal alkynes. The best catalytic performance was obtained at 90 °C using only 0.25 mol % metal loading under copper‐free conditions, in the presence of a H2O/EtOH (3 : 2 v/v) solvent mixture and triethylamine as the base, affording the coupling products in good yields. The Pd/SF‐based protocol was then successfully extended to the synthesis of benzofurans through Sonogashira‐Cacchi type annulation of 2‐iodophenol with terminal alkynes. Preliminary investigations on the recyclability and the heterogeneous behaviour of the catalyst were performed: hot filtration test and leaching test evidenced the presence of a small amount of soluble active palladium species into the reaction mixture. Nevertheless, Pd/SF could be reused in recharging test and it can be recycled in four consecutive runs with no significant deactivation. [ABSTRACT FROM AUTHOR]

Background: Intracerebral hemorrhage (ICH) is a severe form of stroke characterized by high incidence and mortality rates. Currently, there is a significant lack of effective treatments aimed at improving clinical outcomes. Our research team has developed a three-dimensional (3D) biological scaffold that incorporates Bergenin, allowing for the sustained release of the compound. Methods: This 3D biological scaffold was fabricated using a combination of photoinitiator, GEMA, silk fibroin, and decellularized brain matrix (dECM) to encapsulate Bergenin through advanced 3D bioprinting techniques. The kinetics of drug release were evaluated through both in vivo and in vitro studies. A cerebral hemorrhage model was established, and a 3D biological scaffold containing Bergenin was transplanted in situ. Levels of inflammatory response, oxidative stress, and apoptosis were quantified. The neurological function of rats with cerebral hemorrhage was assessed on days 1, 3, and 5 using the turning test, forelimb placement test, Longa score, and Bederson score. Results: The 3D biological scaffold incorporating Bergenin significantly enhances the maintenance of drug concentration in the bloodstream, leading to a marked reduction in inflammatory markers such as IL-6, iNOS, and COX-2 levels in a cerebral hemorrhage model, primarily through the inhibition of the NF-κB pathway. Additionally, the scaffold effectively reduces the expression of hypoxia-inducible factor 1-alpha (HIF-1α) in primary cultured astrocytes, which in turn decreases the production of reactive oxygen species (ROS) and inhibits IL-6 production induced by hemin. Subsequent experiments reveal that the 3D biological scaffold containing Bergenin promotes the activation of the Nrf-2/HO-1 signaling pathway, both in vivo and in vitro, thereby preventing cell death. Moreover, the application of this 3D biological scaffold has been demonstrated to improve drug retention in the bloodstream. Conclusion: This strategy effectively mitigates inflammation, oxidative stress, and cell death in rats with cerebral hemorrhage by inhibiting the NF-κB pathway while concurrently activating the Nrf-2/HO-1 pathway. [ABSTRACT FROM AUTHOR]

Biological and mechanical mismatches between engineered scaffolds and native tissues poses widespread challenges for tissue restoration. Native‐like anisotropy is a critical characteristic for functional tissue replacements, yet it is an often‐overlooked aspect when designing new scaffolds. In this study, fiber‐reinforced tubular scaffolds are developed, mimicking the anisotropic characteristics of natural tissues, using native‐like silk fibroin. To predict the mechanical behavior of these innovative scaffolds, a mathematical model is employed, utilizing the properties of the scaffolds’ constituent materials, and experimentally validated through tensile testing. This approach addresses significant challenges in the design of new scaffold implants by enabling to efficiently predict the performance of several configurations, narrowing down the experimental research space. The proposed platform constitutes an appealing tool for the development of clinically relevant tissue‐equivalents. [ABSTRACT FROM AUTHOR]

The high crystallinity and sophisticated hierarchical architecture of native animal silk endow it with comprehensive mechanical properties that are superior to those of most synthetic fibers. However, these features also make the direct exfoliation of silk nanofibrils (SNFs) highly challenging. On the other hand, silk‐based materials prepared by conventional method (i.e., through silk fibroin aqueous solution) are usually weak, so the preparation methods based on SNFs have attracted much attention in recent years. Herein, a facile and environmentally friendly route is developed to directly exfoliate SNFs from natural Bombyx mori silkworm silk via ammonium persulfate oxidation followed by ultrasonication. The obtained SNFs have a high yield (nearly 40%) and are well dispersed in water in a wide pH range, so they can act as a good starting material to prepare subsequent silk‐based materials. The main application of the SNFs demonstrated in this article is a curcumin (Cur)/SNFs hydrogel as wound dressing. In vivo experimental results show that the Cur/SNFs hydrogel significantly enhanced the healing rate of wounds on diabetic mice. Therefore, the preparation method developed in this study provides an efficient way to produce SNFs, which have great potential for a wide range of applications, including as wound dressings for diabetics. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is a natural biomaterial from silk, which has outstanding biocompatibility. However, regeneration SF materials usually suffer from brittleness, which restricts their applications. Here, a novel supramolecular co‐assembly strategy is reported for the preparation of a Bolas‐shaped polyethylene glycol peptide (BPP)/SF film, where the peptide and SF form a robust payload co‐assembled network and polyethylene glycol (PEG) fragments form supramolecular cross‐linking in this network. The obtained BPP/SF film shows both high stress (27.8 MPa), high toughness (3.64 MJ m−3), high transparency (89%), and high mid‐infrared (MIR) emissivity (90.5%). In passive radiative cooling, the BPP/SF film results in a 2.7 °C reduction in the temperature of the human arm skin and a 14.6 °C reduction in the temperature of the solar cell. More importantly, this novel BPP co‐assembly SF material can be recycled and reused while maintaining its original mechanical strength. This work provides a novel strategy for fabricating regenerative SF materials with ultra‐strong and ultra‐tough mechanical performance. [ABSTRACT FROM AUTHOR]

With exceptional photochromic and photoluminescent properties, spiropyrans have demonstrated significant potential for advanced information encryption and anti‐counterfeiting applications. However, its inherent water insolubility leads to incompatibility with aqueous polymers, and even more, its ease of leaching from the matrix hinders the formation of stable stimuli‐responsive platforms through direct blending with all polymers. Here, the fabrication of amphiphilic spiropyran‐octapeptide molecules is reported that can spontaneously self‐assemble into highly water‐dispersible supramolecular nanofibers in water. These assemblies exhibit universal polymer matrix compatibility while retaining the rapid photo‐responsiveness of spiropyrans. The formation of strong interactions between the supramolecular assembly and polymer chains ensures the long‐term stability of the resultant stimuli‐responsive materials in aqueous environments. These platforms fully preserve the base polymers’ processing properties, with silk fibroin as the matrix offering exceptional opportunities for constructing photo‐responsive platforms in various forms (e.g., films, gels, fibers, and coatings) with multiple functionalities using diverse solution processing techniques. Integrating distinct photochromic and photoluminescent responses within a single format without interference, combined with environmental stability and processing flexibility, enables the creation of dual‐mode, high‐security encryption devices for diverse application scenarios. The outlined strategy provides innovative concepts for developing high‐performance, versatile intelligent systems utilizing stimulus‐responsive molecules. [ABSTRACT FROM AUTHOR]

Vascular covered stents play a significant therapeutic role in cardiovascular diseases. However, the poor compliance and biological inertness of commercial materials cause post-implantation complications. Silk fibroin (SF), as a biomaterial, possesses satisfactory hemocompatibility and tissue compatibility. In this study, we developed a silk film for use in covered stents by employing a layer-by-layer self-assembly strategy with regenerated SF on silk braiding fabric. We investigated the effects on the mechanical properties of the silk films in detail, which were closely correlated with fabric parameters and layer-by-layer self-assembly. The results showed that there was a significant relationship between these factors and both the compliance and mechanical strength. The 1 × 2/90°/100/SF6 film exhibited excellent mechanical properties. Notably, compliance reached 2.6%/100 mmHg, matching that of the human saphenous vein. Thus, this strategy shows promise in developing a novel covered stent, with biocompatible and comprehensive mechanical properties, and significant potential for clinical applications. [ABSTRACT FROM AUTHOR]

Research on sustainable energy sources is crucial for alleviating environmental issues and addressing energy security concerns. This study investigates the utilization of various silk precursors in the hydrogen evolution reaction. Waste silk fabric, regenerated silk fibroin film, porous silk fibroin, silk cocoon and degummed silk fibroin were used as precursors to prepare HER electrocatalysts. To investigate the influence of precursor form on catalytic perform9ance, a comparative analysis of the morphology, structure and composition of different materials was conducted. Among various catalysts, waste silk fabric based catalysts exhibit the most excellent catalytic activity, with an overpotential of 113 mV at 10 mA cm−2 and a Tafel slope of 30.9 mV/dec. Even After 1000 cycles of testing, it still maintains excellent catalytic activity. This study provides insights into the influence of precursor forms on the electrochemical performance of biomass carbon-based catalysts, aiming to inspire further research in this field. • Different precursors can exhibit different structures and properties. • NiCo 2 S 4 demonstrates effective bonding capabilities with diverse precursors. • NiCo 2 S 4 exhibits optimal catalytic activity when combined with WS. • The optimal HER overpotential and C dl are 113 mV and 22.46 mF cm−2, respectively. [ABSTRACT FROM AUTHOR]

Silk fibroins have excellent mechanical properties due to their special structure. A variety of diamino chain extenders containing Gly-Ala-Gly-Ala (GAGA) sequence peptides and a series of modified polyurethanes were prepared. The addition of the tetrapeptide-like structure to the backbone improved the ratio of hydrogen bonds of the modified polyurethane, which resulted in a significant increase in mechanical properties with the strain at break increasing from 29. 3 to 50. 9 MPa. Besides, the shape memory performance of modified polyurethane was also improved with the deformation retention increasing from 74. 3% to 100%. Notably, tetrapeptide content positively correlated with the mechanical property and shape memory performance improvements. Additionally, modified polyurethane containing tetrapeptide-like chain extender also had excellent recyclability, thermal stability and hydrolysis stability under physiological conditions, which can be used in various fields and recycled multiple times. [ABSTRACT FROM AUTHOR]

Background: Non-healing diabetic wounds represent a significant clinical challenge globally, necessitating innovative approaches in drug delivery to enhance wound healing. Understanding the pathogenesis of these wounds is crucial for developing effective treatments. Bioactive dressings and polymeric nanofibers have emerged as promising modalities, with silk biomaterials gaining attention for their unique properties in diabetic wound healing. Purpose of Review: The purpose of this review is to examine the challenges and innovations in treating non-healing diabetic wounds, emphasizing the global burden and the need for effective solutions. This review explores the complex mechanisms of wound healing in diabetes and evaluates the therapeutic potential of bioactive dressings and polymeric nanofibers. Special focus is given to the application of silk biomaterials, particularly silk fibroin, for wound healing, detailing their properties, mechanisms, and clinical translation. This review also describes various nanofiber fabrication methods, especially electrospinning technology, and presents existing evidence on the effectiveness of electrospun silk fibroin formulations. Recent Findings: Recent advancements highlight the potential of silk biomaterials in diabetic wound healing, owing to their biocompatibility, mechanical strength, and controlled drug release properties. Electrospun silk fibroin-based formulations have shown promising results in preclinical and clinical studies, demonstrating accelerated wound closure and tissue regeneration. Summary: Non-healing diabetic wounds present a significant healthcare burden globally, necessitating innovative therapeutic strategies. Bioactive dressings and polymeric nanofibers, particularly silk-based formulations fabricated through electrospinning, offer promising avenues for enhancing diabetic wound healing. Further research is warranted to optimize formulation parameters and validate efficacy in larger clinical trials. [ABSTRACT FROM AUTHOR]

AbstractDamage to articular cartilage is irreversible and its ability to heal is minimal. The development of articular cartilage in tissue engineering requires suitable biomaterials as scaffolds that provide a 3D natural microenvironment for the development and growth of articular cartilage. This study aims to investigate the applicability of a 3D printed CSH (collagen type II/silk fibroin/hyaluronic acid) scaffold for constructing cartilage tissue engineering. The results showed that the composite scaffold had a three-dimensional porous network structure with uniform pore sizes and good connectivity. The hydrophilicity of the composite scaffold was 1071.7 ± 131.6%, the porosity was 85.12 ± 1.6%, and the compressive elastic modulus was 36.54 ± 2.28 kPa. The creep and stress relaxation constitutive models were also established, which could well describe the visco-elastic mechanical behavior of the scaffold. The biocompatibility experiments showed that the CSH scaffold was very suitable for the adhesion and proliferation of chondrocytes. Under dynamic compressive loading conditions, it was able to promote cell adhesion and proliferation on the scaffold surface. The 3D printed CSH scaffold is expected to be ideal for promoting articular cartilage regeneration. [ABSTRACT FROM AUTHOR]

[Display omitted] The skin has a multilayered structure, and deep-seated injuries are exposed to external microbial invasion and in vivo microenvironmental destabilization. Here, a bilayer bionic skin scaffold (Bilayer SF) was developed based on methacrylated sericin protein to mimic the skin's multilayered structure and corresponding functions. The outer layer (SF@TA), which mimics the epidermal layer, was endowed with the function of resisting external bacterial and microbial invasion using a small pore structure and bio-crosslinking with tannic acid (TA). The inner layer (SF@DA@Gel), which mimics the dermal layer, was used to promote cellular growth using a large pore structure and introducing dopamine (DA) to regulate the wound microenvironment. This Bilayer SF showed good mechanical properties and structural stability, satisfactory antioxidant and promote cell proliferation and migration abilities. In vitro studies confirmed the antimicrobial properties of the outer layer and the pro-angiogenic ability of the inner layer. In vivo animal studies demonstrated that the bilayer scaffolds promoted collagen deposition, neovascularization, and marginal hair follicle formation, which might be a promising new bionic skin scaffold. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) can be enzymatically crosslinked through tyrosine residues to fabricate hydrogels with good biocompatibility and tunable mechanical properties. Using tyramine substitution can increase the phenolic group content to facilitate the gelation kinetics and mechanical properties. In this study, a two-step chemical modification method is demonstrated to synthesize silk acid-tyramine (SA-TA) conjugates with a high phenolic group content (>7 mol%). The SA-TA shows rapid enzyme-catalyzed gelation property where the sol–gel transition takes less than 10 s at 37 °C, allowing cell encapsulation with uniform distribution while maintaining high cell viability (>90 %). Furthermore, the enzyme-catalyzed SA-TA hydrogels show enhanced storage modulus than enzyme-catalyzed SF hydrogels, long-term stability, and good cytocompatibility, indicating their great potential in 3D cell culture. The in vivo implantation study demonstrates that the SA-TA hydrogels are biodegradable with a mild immune response. This implies that SA-TA hydrogels can be applied in various medical applications, such as tissue engineering, cell delivery, and 3D bioprinting. In this study, a two-step chemical modification method is demonstrated to synthesize silk acid-tyramine (SA-TA) conjugates with a high phenolic group content (>7 mol%). Owing to the increased content of the phenolic group, the SA-TA shows rapid enzyme-catalyzed gelation property where the sol–gel transition takes less than 10 s at 37 °C, allowing cell encapsulation with uniform distribution while maintaining high cell viability (>90 %). Furthermore, the enzyme-catalyzed SA-TA hydrogels show enhanced storage modulus than enzyme-catalyzed SF hydrogels, long-term stability, and good cytocompatibility, indicating their great potential in 3D cell culture. The in vivo implantation study demonstrates that the SA-TA hydrogels are biodegradable with a mild immune response. This implies that SA-TA hydrogels can be applied in various medical applications, such as tissue engineering, cell delivery, and 3D bioprinting. [Display omitted] [ABSTRACT FROM AUTHOR]

Mannich‐type dyeing of silk fibroin with aromatic primary amine dyes (APADs) is a novel reactive dyeing method that requires mild conditions and exhibits high selectivity and good wet fastness. However, the primary amine group in the APADs significantly decreases the photostability of Mannich‐type dyed silk fabrics. To reveal the structure–activity relationship and photofading mechanism of the APADs by Mannich‐type dyeing, six pyrazolone‐containing APADs with similar structures were designed and synthesised. Variation in amino electron density among the dye analogues was related to differences in colour fixation of the Mannich‐dyed fabrics, as determined from the calculated Mulliken charge densities. Using mass spectrometry to monitor the photodecomposition of the dyed silk, it is demonstrated that the Mannich‐type dyed silk fabrics undergo photooxidative fading, in contrast to the conventional acidic‐type dyed fabrics that undergo photoreductive fading. Furthermore, it is shown that the Mannich‐type dyed silk fabric has a higher light fastness than conventional acidic‐type dyed fabrics using the same pyrazolone‐containing APADs. Evaluation of dye dipole moment and Mannich‐type dyeing shows that the APADs with increased dipole moments generally demonstrated increased light fastness. [ABSTRACT FROM AUTHOR]

In this study, a novel array electrospinning collector was devised to generate two distinct regenerated silk fibroin (SF) fibrous membranes: ordered and disordered. Leveraging electrostatic forces during the electrospinning process allowed precise control over the orientation of SF fiber, resulting in the creation of membranes comprising both aligned and randomly arranged fiber layers. This innovative approach resulted in the development of large‐area membranes featuring exceptional stability due to their alternating patterned structure, achievable through expansion using the collector, and improving the aligned fiber membrane mechanical properties. The study delved into exploring the potential of these membranes in augmenting wound healing efficiency. Conducting in vitro toxicity assays with adipose tissue‐derived mesenchymal stem cells (AD‐MSCs) and normal human dermal fibroblasts (NHDFs) confirmed the biocompatibility of the SF membranes. We use dual perspectives on exploring the effects of different conditioned mediums produced by cells and structural cues of materials on NHDFs migration. The nanofibers providing the microenvironment can directly guide NHDFs migration and also affect the AD‐MSCs and NHDFs paracrine effects, which can improve the chemotaxis of NHDFs migration. The ordered membrane, in particular, exhibited pronounced effectiveness in guiding directional cell migration. This research underscores the revelation that customizable microenvironments facilitated by SF membranes optimize the paracrine products of mesenchymal stem cells and offer valuable physical cues, presenting novel prospects for enhancing wound healing efficiency. [ABSTRACT FROM AUTHOR]

In this work, the effect of incorporating silk fibroin, a fibrous biocompatible protein, into physically cross-linked agarose hydrogels was investigated as a simple model study to examine how supramolecular fibrous structures influence the properties of the hydrogels. The rheological and transport properties were studied. Fibroin did not change the general viscoelastic properties of the investigated hydrogels but changed the viscoelastic moduli values and also the mesh size, as calculated from rheometry data. Fibroin influenced the mechanical properties depending on its concentration: at lower concentrations, it increased the mesh size, while at higher concentrations, it acted as a filler, decreasing the mesh size. Similarly, the storage and loss moduli were affected, either increasing or decreasing based on the fibroin concentration. The fibroin effect on the diffusion of two dyes differing in their charge was the result of a combination of structural effects, responsible also for changes in the rheological properties, and a result of electrostatic interactions between the charged groups. For positively charged methylene blue, low fibroin concentrations accelerated diffusion, while higher concentrations slowed it by filling network vacancies. In contrast, for negatively charged eosin-B, fibroin strongly impeded diffusion at all concentrations due to electrostatic repulsion, leading to its accumulation at the hydrogel interface. The findings of this work may contribute to an understanding of the behavior of the extracellular matrix or soft tissues as well as to the development of the tailored design of hydrogel materials. [ABSTRACT FROM AUTHOR]

Nanocomposites selectively induce cancer cell death, holding potential for precise liver cancer treatment breakthroughs. This study assessed the cytotoxicity of gold nanocomposites (Au NCs) enclosed within silk fibroin (SF), aptamer (Ap), and the myogenic Talaromyces purpureogenus (TP) against a human liver cancer cell (HepG2). The ultimate product, Ap-SF-TP@Au NCs, results from a three-step process. This process involves the myogenic synthesis of TP@Au NCs derived from TP mycelial extract, encapsulation of SF on TP@Au NCs (SF-TP@Au NCs), and the conjugation of Ap within SF-TP@Au NCs. The synthesized NCs are analyzed by various characteristic techniques. Ap-SF-TP@Au NCs induced potential cell death in HepG2 cells but exhibited no cytotoxicity in non-cancerous cells (NIH3T3). The morphological changes in cells were examined through various biochemical staining methods. Thus, Ap-SF-TP@Au NCs emerge as a promising nanocomposite for treating diverse cancer cells. [ABSTRACT FROM AUTHOR]

Abstract Background Intracerebral hemorrhage (ICH) is a severe form of stroke characterized by high incidence and mortality rates. Currently, there is a significant lack of effective treatments aimed at improving clinical outcomes. Our research team has developed a three-dimensional (3D) biological scaffold that incorporates Bergenin, allowing for the sustained release of the compound. Methods This 3D biological scaffold was fabricated using a combination of photoinitiator, GEMA, silk fibroin, and decellularized brain matrix (dECM) to encapsulate Bergenin through advanced 3D bioprinting techniques. The kinetics of drug release were evaluated through both in vivo and in vitro studies. A cerebral hemorrhage model was established, and a 3D biological scaffold containing Bergenin was transplanted in situ. Levels of inflammatory response, oxidative stress, and apoptosis were quantified. The neurological function of rats with cerebral hemorrhage was assessed on days 1, 3, and 5 using the turning test, forelimb placement test, Longa score, and Bederson score. Results The 3D biological scaffold incorporating Bergenin significantly enhances the maintenance of drug concentration in the bloodstream, leading to a marked reduction in inflammatory markers such as IL-6, iNOS, and COX-2 levels in a cerebral hemorrhage model, primarily through the inhibition of the NF-κB pathway. Additionally, the scaffold effectively reduces the expression of hypoxia-inducible factor 1-alpha (HIF-1α) in primary cultured astrocytes, which in turn decreases the production of reactive oxygen species (ROS) and inhibits IL-6 production induced by hemin. Subsequent experiments reveal that the 3D biological scaffold containing Bergenin promotes the activation of the Nrf-2/HO-1 signaling pathway, both in vivo and in vitro, thereby preventing cell death. Moreover, the application of this 3D biological scaffold has been demonstrated to improve drug retention in the bloodstream. Conclusion This strategy effectively mitigates inflammation, oxidative stress, and cell death in rats with cerebral hemorrhage by inhibiting the NF-κB pathway while concurrently activating the Nrf-2/HO-1 pathway.

Abstract Vascular covered stents play a significant therapeutic role in cardiovascular diseases. However, the poor compliance and biological inertness of commercial materials cause post-implantation complications. Silk fibroin (SF), as a biomaterial, possesses satisfactory hemocompatibility and tissue compatibility. In this study, we developed a silk film for use in covered stents by employing a layer-by-layer self-assembly strategy with regenerated SF on silk braiding fabric. We investigated the effects on the mechanical properties of the silk films in detail, which were closely correlated with fabric parameters and layer-by-layer self-assembly. The results showed that there was a significant relationship between these factors and both the compliance and mechanical strength. The 1 × 2/90°/100/SF6 film exhibited excellent mechanical properties. Notably, compliance reached 2.6%/100 mmHg, matching that of the human saphenous vein. Thus, this strategy shows promise in developing a novel covered stent, with biocompatible and comprehensive mechanical properties, and significant potential for clinical applications.

Although natural polymers have been widely used in constructing bone scaffolds, it still remains challenging to fabricate natural polymer-derived bone scaffolds with biomimetic mechanical properties as well as outstanding osteogenic properties for large-size and weight-bearing bone defects regeneration. Herein, an “organic-inorganic assembly” strategy is developed to construct silk fibroin (SF)-based bone scaffolds with the aforementioned merits. After secondary structure reshuffling, the 3.3-fold increment of β-sheet structures in SF hydrogel resulted in a 100-fold improvement of mineral-assembly efficacy via influencing the ion adsorption process and providing templates for mineral growth. Notably, abundant minerals were deposited within the hydrogel and also on the surface, which indicated entire mineral-assembly, which ensured the biomimetic mechanical properties of the digital light processing 3D printed SF hydrogel scaffolds with haversian-mimicking structure. In vitro experiments proved that the assembly between the mineral and SF results in rapid adhesion and enhanced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells. In vivo experiments further proved that the mineral-assembled SF hydrogel scaffold could significantly enhance integration and bone regeneration at the weight-bearing site within one month. This SF-based “organic-inorganic assembly” strategy sheds light on constructing cell-free, growth factor-free and natural polymer-derived bone scaffolds with biomimetic 3D structure, mechanical properties and excellent osteogenic properties.

[Display omitted] • A simple and efficient method for reinforcing and protecting aged silk was developed. • The homologous silk fibroin of aging silk can replenish the protein components lost in aging degradation of silk. • The acyl transfer reaction between silk fibroin and carboxymethyl chitosan was catalyzed by transglutaminase. • The reinforced aged silk has excellent mechanical properties and antibacterial properties. The reinforcement and preservation of historical silk are crucial for its continued research, heritage, and display. Herein, silk fibroin (SF) and carboxymethyl chitosan (CMCS) were utilized as raw materials to reinforce aged silk via two reinforcement methods, with transglutaminase (TGase) serving as a catalytic cross-linking agent. The covalent and non-covalent bond network formed by TGase catalytic cross-linking significantly improved the mechanical properties of aging silk, and CMCS as an antibacterial material gave excellent antibacterial properties of the aged silk. Compared with aged silk, the breaking stress and elongation at break of the aged silk after reinforcement are increased by 257.9% and 293.7% respectively. The antibacterial rate of the reinforced aged silk against Escherichia coli (E. coli) and Streptococcus aureus (S. aureus) exceeded 90%. Under accelerated simulated aging conditions, the aging rate of the reinforced silk was significantly reduced, demonstrating notable aging resistance. Notably, the one-step enhanced aged silk outperformed the two-step enhanced aged silk in all performance evaluations, while the appearance of the aged silk was not affected. This work provides a green and efficient process for the reinforcement and protection of silk-based cultural relics and the application of silk cultural relics protection materials. [ABSTRACT FROM AUTHOR]

In this study, the electrospinning technique was employed to create a nanofiber membrane by stretching an organic polymer into nanofibers under a high electric field. Metronidazole (MNZ) at a concentration of 3 wt% was loaded into a poly(lactic-co-glycolic acid) (PLGA) and silk fibroin (SF)-blended nanofiber membrane. This formulation aims to achieve effective and sustained drug release, enabling the eradication of bacteria for the efficient treatment of periodontitis. Results demonstrated that SF interacted with PLGA molecules, forming dense and uniform nanofibers with a diameter of 570 nm. Excessive SF molecules tended to aggregate, leading to an increased particle size, with the interaction between MNZ and SF contributing to adhesion. The composition of MNZ, SF, and PLGA formed a physical chimera without any chemical reactions. Moreover, as the SF content increased, the tensile properties of the membrane gradually improved. Concurrently, the in vitro degradation rate increased with higher SF content. Among the various groups tested, the 3 wt% MNZ/PLGA/SF 2:1 membrane exhibited superior drug release characteristics, with 71.76% release within 24 h. This formulation demonstrated excellent antibacterial properties, indicated by a bacterial inhibition diameter of 13.5 mm, noteworthy hydrophilicity with a contact angle of 44.3°, and favorable biocompatibility. The membrane holds significant application value in regenerative engineering and drug delivery systems, showcasing substantial potential for the treatment of periodontitis.

Highlights Site-selective superassembly was used to synthesize a nanorobot with bionic rod-shaped head/hollow tail structure, exhibiting strong photothermal effect, high drug loading capacity, precise and controlled drug release, and excellent motility. Injectable regenerated silk fibroin (RSF) nanofibril hydrogels were developed via simple sonication, offering significant production, structural, and performance advantages. Nanorobot/thrombin (Thr)/RSF nanofibril hydrogels reduced intraoperative bleeding of hepatocellular carcinoma (HCC) spinal metastasis, provided starvation embolization, and prevented post-surgery recurrence. Nanorobot/Thr/RSF nanofibril hydrogels inhibited blood supply to residual tumors and reduced neovascularization, inhibiting post-surgery HCC spinal metastasis recurrence.