Papers by Keyword: Silk Fibroin

Abstract: Silk fibroin (SF), chitosan (C), and gelatin (G) blend composition in formic acid have been manufactured by using electrospinning technique in our previous work. The SF: G: C at weight ratios of 10: 20: 1 and 20: 10: 1 (%wt: %wt: ml) were used for crosslinking testing. Glutaraldehyde (GA), and 1-ethyl-3-(3-dimethylaminopropyl) cabodiimide (EDC) / N-hydroxy succcinimide (NHS) (EDC/NHS) were chose as crosslinking agents. All samples were treated in such agents by fumigation for 72 hours followed by dipping for 10 minutes. Then those samples were washed in distill water for 3 times (1 time per 10 minutes) and dried in desiccator at room temperature. GA caused immediately shrink in both nanofiber mats and became clearly visible yellowish. However, a little shrinkage occurred after dipping in EDC/NHS. It possibly concluded that the EDC / NHS appropriated for SF: G: C blend nanofiber mats.

Abstract: Scaffolds with mechanical properties that mimic the tissue to be restored are critical to maintain the morphology and function of a scaffold after implantation and during tissue regeneration. Silk fibroin (SF), a protein from the Bombyx mori silk worm cocoon, is currently employed in the biomedical field and tissue engineering. The objective of this study was to construct three-dimensional porous silk fibroin/alpha tricalcium phosphate scaffolds for bone tissue engineering application. The scaffolds were fabricated 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). Alpha tricalcium phosphate (α-TCP) was incorporated to produce 4, 8, 12, and 16 wt% solution and sucrose (particle size 250-450 μm; sucrose/silk fibroin = 8.5/1 w/w) was used as a porogen. The microstructure and pore size, calcium and phosphorus contents, and compressive modulus were evaluated. The scanning electron microscope images revealed the microstructure of scaffolds to be square shaped with continuous interconnected pores. The average pore size of the scaffolds was 265.70 + 67.45 μm. The scaffolds containing 8% (w/w) α-TCP exhibited the highest compressive modulus (64.84 + 16.65 kPa) and the highest calcium content. The results suggested that the scaffolds containing α-TCP may be a potential candidate for application in bone tissue engineering applications.

Abstract: Nowadays biosensors have been extensively used in a wide variety of applications especially in clinical works and food industry. In this work, a specific ascorbic acid (AA) biosensor was developed by immobilizing ascorbate oxidase (ASOD) on a polyethylene glycol (PEG) modified silk fibroin (SF) membrane then coupling to the glassy carbon electrode (GCE). The SF-PEG-ASOD membrane provided the highest enzyme activity in phosphate buffer at pH 5. As being the electrode, the SF-PEG-ASOD modified GCE displayed the highest response when it is operated under the condition of 0.40 mg/L of ASOD in phosphate buffer at pH 5. This biosensor provided both good linearity (r² = 0.999 in the range of 1.0-10.0 mM) and sensitivity with short response time (26s). It also exhibited good anti-interference ability with the storage time of 5 days without changing its initial response.

Abstract: In this study, Chitosan (CS), Silk Fibroin (SF), and Hydroxyapatite (HA) were selected for scaffold fabrication. The scaffolds were fabricated by freeze drying technique to produce a porous structure. Silk cocoons and bovine bone were used to synthesize the SF and HA, respectively. While CS was produced from commercialized product made from squid pen. The CS was selected as a main structure of the scaffold which was fixed at 50% by weight ratio of the specimen. Another fifty percent are the various ratio of HA and SF. The result confirmed the extraction of silk cocoons and bovine bones were acceptable used as HA and SF. The HA and SF ratio that provided the highest porosity percentage was 25:25, while the highest percentage of cells growth in 7 and 21 days was 50:0 ratio. According to MTT-assay results, the scaffolds in every ratio could be used as a tissue engineering structure for cell proliferation as well as cartilage repairing in the future.

Abstract: In this study, nanofibres consisting of silk fibroin (SF) and gelatin (GP) with different composition ratio were fabricated by needleless electrospinning method. The influences of SF/GP blending ratio on the properties of spinning solution and the morphology of electrospun fibres were investigated. A variety of compositions of the silk fibroin/gelatin blend solutions were successfully electrospun into nanofibres sheet. The morphology of electrospun fibre was characterized by a scanning electron microscope (SEM) which indicates that the morphology of obtained fibres was influenced by the weight ratio of gelatin to silk fibroin in the spinning solution. It was observed that the blending ratio of gelatin to silk fibroin in spinning solution played an important role in spinning performance of the process and the diameter of obtained fibres. An increasing in gelatin content in blended solution resulted in bigger diameter of the obtained electrospun fibres. The silk fibroin/gelatin electrospun fibres had diameters ranging from 200 to 660 nm.

Abstract: Silk fibroin, gelatin, and chitosan blended solution in formic acid with different composition ratios were electrospun. The fiber could be produced from SF:G : C blended solution at weight blending ratios (%wt: %wt: ml) of 10:20:0, 10:20:0.5, 10:20;1, 10:20:1.5, 10:20:2, and 20:10:1. When the chitosan content in blended solution increased, the average diameter decreased from 245 to 100 nm and fiber size distribution was narrow. The SF: G: C solution at ratio of 10:20:1 under high electric field and long spinning distance provided the continuous and uniform fibers. The formic acid as solvent did not affect to the electrospinnability and morphology of SF: G: C blended nanofiber. Tensile strength of SF: G: C (10:20:1) blended nanofiber was decreased with increasing of silk fibroin content, SF: G: C (20:10:1). The results indicated that SF: G: C electrospun nanofiber mats could be prepared and have a potential to be applied in membrane application.

Abstract: The composite tubular scaffolds with highly oriented nanofibers used for vascular repair could improve the biomechanical properties of tubular scaffolds, satisfying the biomechanical requirement for the change of blood pressure and conducing to cell adhesion, migration and proliferation. The tubular scaffolds from poly(ε-caprolactone)(PCL) and silk fibroin (SF) composite nanofibers were successfully fabricated through electrospinning using cylindrical roller with an outer diameter (OD) of 3.0 mm. The influences of the collecting rotatation speeds on electrospun PCL/SF nanofibers orientation and radial/axial mechanical properties of the scaffolds were investigated. The results revealed that the electrospun PCL/SF tubular scaffolds fabricated at 1500 and 2000 r/min (linear velocity of 2.1, 2.8 m/s, respectively) possessed good arrangement around the circumferential direction of roller and sufficient radial strength and suture strength. The electrospun PCL/SF tubular scaffolds with circumferential-direction structure as a new vascular graft may be useful in vessel tissue engineering.

Abstract: Antheraea pernyi silk fibroin has favorable biocompatibility, good bioactivity and controllable biodegradability, meeting the basic requirements of controlled drug release carriers. Enhancing the negative charge of silk fibroin could further increase the encapsulation and loading efficiency of positively charged drugs. In this study, Antheraea pernyi silk fibroin was chemically modified by methylglyoxal in aqueous solution. The electric charge properties of Antheraea pernyi silk fibroin were examined to characterize the modification, the results indicated that the isoelectric point of Antheraea pernyi silk fibroin decreased from 4.5 to 3.9, and the zeta potential reduced from-11.7 mV to-12.8 mV. Amino acid analysis and ¹H-NMR spectra showed that arginine residue of Antheraea pernyi silk fibroin side chain was modified by methylglyoxal for enhancing negative charge of silk fibroin. These results suggested that methylglyoxal-modified Antheraea pernyi silk fibroin could be considered as a potential starting material in loading positively charged drugs.

Abstract: Corneal transplantation is the only effective way to repair the damaged corneal tissue and solve the problem of insufficient donor cornea and immune rejection. Biocompatibility and stable transparent are necessary conditions of corneal stromal cells carrier. In this paper, the acetamide/silk (AC/SF) composite membranes are studied to be applied in corneal repair material. AC/SF membranes with different blending proportions had stable transparency, good cell compatibility. X-ray diffraction was used to investigate the structure of the composite films. The acetamide inhibited the formation of large crystalline particles, changed the crystal structure of silk fibroin and made the random coil structure convert to Silk I or Silk II. Therefore, acetamide was not only crosslinking agent but also crystallization inhibitor. The corneal stromal cells were seeded on sterilized composite membranes. After 5 h, the adhesion rate of stromal cells was more than 90%, cell could proliferate regularly on the composite membrane. There was no obvious difference in contrast to control plate. These results demonstrated that the composite membrane could promote corneal stromal cell proliferation.

Abstract: Various methods were developed to prepare hydrogels including photo-cross-linking, chemical cross-linking, enzymatic cross-linking, pH or temperature-induced gelation, ionic interaction, and hydrophobic interactions. Whereas silk fibroin gelation time was difficult to control by physical methods, the cross-linkers used in chemical technique were likely to reduce the cell biocompatibility. Sodium N-Lauroyl Sarcosinate (SNS), an amino acid-based surfactant, came into accelerate silk fibroin to form silk hydrogel. To monitor the gelation process and determine the gelation time, turbidity changes during gelation were measured by Synergy HT. Cylindrical gels have been measured with universal material experiment machine and KES for mechanical properties. Fibroblast (L929) cells were seeded on the surface of hydrogels to investigate the cell compatibility. The results show that the SNS/SF gelation time ranges from 20 min to 120 min, which is affected by environment temperature, the final concentrations of SF and SNS. Compared with pure silk fibroin hydrogels, the compression strength of SNS/SF gel is much stronger. SNS/SF gel has excellent compression-recovery performance in KES test as well. A logarithmic stable cell growth appears on the surface of SNS/SF hydrogels, which indicates that SNS/SF hydrogels have excellent cell compatibility. Therefore, the SNS/SF hydrogels have great potential in tissue repair for surgery.