Papers by Keyword: Silk Fibroin

Abstract: Tissue engineering has focused on the development of biomaterials, modulating the morphological and electrochemical characteristics based on their final application. In this setting, the purpose of the present study was to determine the physicochemical response of electrospun membranes of silk fibroin extracted from sericulture wastes and their functionalization with choline based bio-ionic liquids. A comparative study of their response was carried out with membranes obtained from the same protein but functionalized with gold nanoparticles. The biomaterials developed were characterized by UV-Visible spectrophotometry, FTIR spectroscopy, electron microscopy (SEM and FESEM), dynamic light scattering (DLS), and Linear sweep voltammetry. The results obtained showed a fibrillar morphology and the conduction of electrical stimuli by the membranes functionalized with the gold nanoparticles or the bio-ionic liquids, where for the latter the response is modulated by the concentration used in the development of the biocomposite.

Abstract: In recent years, developments in medical devices have led to research in drug release mechanisms. Although important advances have been made, some critical points still exist to investigate. Regarding materials to be used for drug purposes some natural materials seem to be a biocompatible future solution. Silk fibroin (SF) is one of the proposed candidates to satisfy the needs of drug release technologies due to its biodegradability in a tunable range of time with non-toxic end products. This work aims to study the dip coating process over stainless steel and polyurethane tubes to obtain micro-coating layers for drug release purposes. The effect on the number of cycles (2, 4, and 8) and evaporation time between cycles (10, 20, and 30 seconds) was studied. The layer thickness of the coating and the degradation rate in water were analyzed. Results showed that silk fibroin coatings at the microscale can be achieved. Furthermore, a strong influence of the evaporation time over the layer thickness with a maximum decrease of 66,1% as the evaporation time increases and an increase of 63,8% as the number of cycles increases. Results showed a high degradation rate in PBS with a 70,5% of weight loss relative to the initial weight of SF degraded within 3 hours.

Abstract: Bioresorbable alternatives are emerging on the market as alternatives to the cardiovascular stents that are implanted nowadays. Permanent drug-eluting stents are no longer the only viable option during an angioplasty surgical procedure. The new generation of medical stents aims to degrade the device within the artery walls after its function has been completed. In this context, biological materials that degrade inside the body without creating toxic residues such as silk fibroin (SF) are very promising materials for such applications. Moreover, SF has been reported to have non-thrombogenic properties and to reduce the immune response compared to other synthetic polymers, making it ideal for this application. SF has been printed through additive manufacturing techniques such as direct ink write. This study proposes to fabricate a composite stent by combining polylactic acid (PLA) and SF. In this way, it is expected to obtain a stent with potential for a two-phase drug release. A fast burst with the degradation of the SF and a slower drug release period with the degradation of the PLA. For this purpose, stents were fabricated with a PLA and chloroform ink (24.5 % w/v). The last layer of the stent was fabricated with a SF water-based ink at 56.69-60.09 % w/w. Finally, the stents were immersed at different times in ethanol and exposed to 30' of ultraviolet light for sterilization purposes. The degradation results indicate that 24h is sufficient to degrade almost completely the last layer of SF. These results are significant as the SF layer could potentially be used as a carrier for drug delivery, providing biocompatibility and drug release at the earliest post-intervention stage.

Abstract: Silk fibroin can be derived from the silkworm Bombyx mori and it has the main properties for its use as bioadhesive biomaterial in medicine – biocompatibility, good mechanical properties and controllable degradation rate. On the other hand hyaluronic acid (HA) is an attractive polymer for biomedical applications, due to its biological and structural importance, as well as its ease of modification. Thus in this study, two types of silk raw materials for preparation of silk fibroin (SF) solutions were used. Obtained SF solutions with and without hyaluronic acid (HA) were cross-linked to form hydrogels. Widely used cross-linking agent glutaraldehyde (GTA) was used in this study. Two temperatures 37°C and 60°C were chosen to determine the effect of temperature on the cross-linking rate of the samples. The gelation time, swelling ratio and structural features of the adhesive were also studied.

Abstract: Patients suffering from cardiovascular disease lack suitable stent. In this study, a new polymeric composite material was prepared by incorporating various concentrations of gamma-glycidoxypropyltrimethoxysilane (GPTMS) into silk fibroin (SF), aiming at achieving a novel composite film with superior mechanical and biological properties, in order to match the requirement of cardiovascular tissue engineering stents. Fourier transform infrared spectroscopy (FTIR) analysis showed that GPTM could promote SF to transform from the original alpha helix and random coil/extension chain conformation to the beta-folded conformation. Tensile experiment indicated tensile strength and breaking elongation of SF/GPTMS hybrid film reach the maximum with 20% GPTMS content. Within a certain range, the water drop contact angle of SF/GPTMS hybrid film is positively correlated with the content of GPTMS. Endothelial cells (ECs) are best grown on hybrid SF/GPTMS hybrid film with 20% GPTMS content.

Abstract: Wound healing is a natural process of human body. When the wound size exceeds the critical point for naturally body healing, the fibrous tissue will play their parts and created a scar. Therefore, extra treatment has been added to eliminate the body limitations. Currently, there are a lot of commercial bioactive wound healing and dressing due to its physiological and biological abilities. In wound healing process, high moisture condition is also required. In order to accelerate the wound healing process, Tissue engineering (TE) is recommended. The increasing of cell proliferation by TE will be increased the chance for wound healing acceleration. In this study, the combination of Gelatin (Gel), Chitosan (CS) and Silk Fibroin (SF) were varied mixed in 10 ratios and fabricated the structure by lyophilisation technique. The elastic ability, biodegradability, structure and pore morphology, porosity, swelling ability, and biotoxicity were observed in each ratio. Gel provided highest elastic ability and biodegradability. The addition of SF and CS in Gel decreased biodegradation rate and activate fibroblast cell proliferation. Therefore, CS and SF could increase efficiency of gelatin-base wound dressings for a variety of utilization.

Abstract: Background: Currently silk fibroin is used more and more in the biomedical researches, including a potential research direction in creating wound dressing. Turmeric powder is a natural drug with many properties suitable for treatment of burns such as anti-inflammatory, anti-bacterial, anti-fungal, especially reducing formation of scars. Methods: In this study, sericin is removed from the silk to obtain fibroin fiber. Fibroin fiber and turmeric powder are dissolved by formic acid adding calcium chloride (CaCl₂). Created fibroin films (FF) are then evaluated in some characteristics such as surface structure, chemical structure, tensile strength, absorbency, dehydration rate, biodegradation ability, pH determination, preventing bacteria ability and cytotoxicity test. Results: All results indicated that created FF is fulfilled with all the required properties of wound dressings. Conclusions: This study is the first step to creating foundation and orientation for the development of commercial wound dressings.

Abstract: Silk fibroin is a natural biodegradable polymer that has been demonstrated for use as scaffolds for bone tissue engineering. To improve the osteoconductivity and the osteoinductivity of silk fibroin scaffolds, ceramics were added. α-tricalcium phosphate (α-TCP) is the expected ceramic that useful for scaffolds for bone tissue engineering either alone or blended with silk fibroin. From the previous study, we evaluated the mechanical properties of three-dimensional porous silk fibroin/ α-TCP scaffolds and concluded that the scaffolds containing 8% (w/w) α-TCP exhibited the highest compressive modulus. The objective of this study was to evaluate the biological properties of three-dimensional porous silk fibroin/α-TCP scaffolds. The scaffolds were constructed using a solvent casting and salt leaching technique. The hybrid strain of degummed Thai silk fibroin, Nangnoi Srisaket 1 x Mor, was dissolved in hexafluoroisopropanol at 16% (w/v). α-TCP was incorporated to produce 4, 8, 12, and 16 wt% solution. Sucrose (particle size 250-450 μm; sucrose/silk fibroin = 8.5/1 w/w) was used as a porogen. Human gingival fibroblasts (passage 5) were cultured in these scaffolds. After 72 h, the biocompatibility of seeded scaffolds was evaluated under the inverted phase contrast microscopy. Cell proliferation was determined by DNA assays and scanning electron microscopy. The images from inverted phase contrast microscopy revealed the human gingival fibroblasts can be attached at the surface of scaffolds in all groups. The results from the DNA assays showed that the number of human gingival fibroblasts was increased as the culture period was prolonged but was not as the increasing of α-TCP. At 120 h, the scaffolds containing 8% (w/w) α-TCP exhibited the highest cell number. The scanning electron microscope images at 24, 72, and 120 h after cell culturing presented human gingival fibroblasts can be expanded well and exhibited the normal morphology. The results suggested that the scaffolds containing 8% (w/w) α-TCP may be a potential candidate for bone tissue engineering applications.

Abstract: A novel silk fibroin (SF) based bi-layered wound dressing was successfully developed by spraying chitosan (CS) solution on the ring spun silk fibroin fabric. SEM micrographs showed that chitosan solution formed a thin film on the degummed silk fibroin fabric, which had a connective porous structure. The antibacterial property, indirect cytotoxicity and the wound healing properties of the materials were investigated. Comparing with the commercial wound dressing, the bi-layered SF/CS wound dressing could accelerate the wound healing, and may be a potential choice for skin regeneration.

Abstract: There is a need for high performance scaffold in tissue engineering. Keeping this perspective in mind, the present study delineates the preparation and physico-chemical characterization of soluble eggshell protein (SEP) modified silk fibroin (SF)-polyvinyl alcohol (PVA) scaffold and its application in bone tissue engineering. The SF/PVA scaffold were prepared by salt leaching and modified with eggshell protein. Micro-architechture and porosity analysis revealed that all the scaffolds were having desired pore size (230-360 µm), interconnected porous network and 90% porosity. The scaffolds were found with suitable swelling behavior and biodegradability to support cell proliferation till replaces native osseous tissue. In vitro cyto-compatibility and differentiation study showed that SEP(SF-PVA) supports viability , proliferation and differentiation of cord blood derived human mesenchymal stem cell. Further, in vivo study in mice model showed that the scaffolds are non-immunogenic and support tissue growth. In conclusion, SEP modified SF-PVA scaffold could be a better option for tissue engineering.