• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.129-132
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• 2012

Silk fibroin films incorporated with tetracycline was prepared and characterized by Fourier-transform infrared spectrometer and differential scanning calorimeter and examined antibacterial effect. The conformation of silk fibroin was changed from random coil to $\hat{a}$ sheet structure with incorporation of tetracycline. Antibacterial activity of the materials was evaluated against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus epidermis, and Staphylococcus aures) using agar plate method showing clear inhibition zone around tetracycline silk film. It is concluded that tetracycline-incorporated SF films are highly effective against bacteria.

• Journal of Sericultural and Entomological Science
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• v.49 no.2
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• pp.74-76
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• 2007

Antheraea yamamai silk fibroin powder was prepared by treatment with HCl. Amino acid contents of the prepared Antheraea yamamai fibroin hydrolysates were composed of Gly, Ala, Glu, and so on. Biological activities of Antheraea yamamai silk fiborin powder were examined. It is showed about 75% of antioxidation activity compared to the reference ascorbic acid. And it lowered blood glucose level down from 550 mg/dl to 300 mg/dl by serving with wild silk protein.

• Journal of Sericultural and Entomological Science
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• v.18 no.2
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• pp.101-105
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• 1976

The study was carried out to investigate the variations in the fibroin hydrolysis of leading silkworm varieties in Korea, and the relationship between the fibroin hydrolysis of the silkworm varieties with some characteristics and silk morphological property. The results obtained are summarized as follows: 1) The fibroin hydrolyzing ratio of both parent silkworm cocoons was reduced in the F$_1$hybrids. 2) A positive corelation (r=＋0.86) was approved between the mid-parent value and the F$_1$hybrid in the fibroin hydrolysis. 3) It was disclosed that the fibroin hydrolyzing ratio of Jam 103${\times}$Jam 104 was the lowest among the leading silkworm F$_1$hybrids. 4) The fibroin hydrolysis was affected by the silk morphological property, showing a positive corelation between the size of cocoon filament and the fibroin hydrolyzing ratio. 5) It was thought that the determination of the fibroin hydrolyzing ratio was useful as a marker for the selection of its related economical characters in silkworm breeding, because the fibroin hydrolysis of parents silkworm cocoons was heritable in their F$_1$hybrids.

• Polymer(Korea)
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• v.35 no.5
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• pp.378-384
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• 2011

Silk fibroin is a biocompatible and slowly biodegradable natural polymer. This natural polymer has excellent mechanical properties, non-toxicity, and non-immunogenic properties and has been demonstrated to support tissue regeneration. Also, gelatin is a natural material derived from collagen by hydrolysis and has an almost identical composition as that of collagen. Silk fibroin/gelatin scaffolds have been fabricated by using the freeze-drying method. To establish the scaffold manufacturing condition for silk fibroin and gelatin, we made scaffolds with various compositions of gelatin, glutaldehyde and silk fibroin. The silk fibroin/gelatin scaffolds were characterized using SEM, DSC, and water absorption ability tests. The cellular proliferation was evaluated by WST assay. These results suggested that a scaffold containing 8% of gelatin, 1% of glutaldehyde and 0.3 g of silk fibroin provided suitable characterstics for cell adhesion and proliferation. In conclusion, the silk fibroin/gelatin scaffold may serve as a potential cell delivery vehicle and a structural basis for tissue engineering.

• International Journal of Industrial Entomology and Biomaterials
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• v.45 no.2
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• pp.70-77
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• 2022

Wet-spun regenerated silk fibroin (RSF) fibers have been extensively studied owing to their 1) useful properties as biomaterials, including good blood compatibility and cyto-compatibility; 2) the various methods available to control the structural characteristics and morphology of the fiber, and 3) the possibility of fabricating blended fibers and new material-embedded fibers. In this study, silk nanofibrils prepared using a new method were embedded in RSF to fabricate wet-spun silk nanofibril/RSF composite fibers. Up to 2% addition of silk nanofibril, the silk nanofibril/RSF dope solution showed slight shear thinning, and the G' and G" of the dope solution were similar. However, above 3% silk nanofibril content, the viscosity of the dope solution significantly increased. In addition, shear thinning was remarkably evident, and the G' of the dope solution was much higher than the G", indicating a very elastic state. As the silk nanofibril content was increased, the wet-spun silk nanofibril/RSF composite fiber became uneven, with a rough surface, and more beaded fibers were produced. Scanning electron microscopy observations revealed that the beaded fibers were attributed to the inhomogeneous dispersion and presence of agglomerates of the silk nanofibrils. As the silk nanofibril content and RSF concentration increased, the maximum draw ratio decreased, indicating the deterioration of the wet spinnability and post-drawing performance of silk nanofibril/RSF.

• International Journal of Industrial Entomology and Biomaterials
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• v.30 no.1
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• pp.17-25
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• 2015

This study aimed to investigate the effects of silk fibroin on bone metabolism in ovariectomized rats. A total of 30 Sprague-Dawley rats were randomized into sham-operated (SHAM), ovariectomized control (OVX), alendronate (OVX+ALEN, 10 mg/kg body weight/d), low silk fibroin (OVX+SF100, 100 mg/kg body weight/d), and high silk fibroin (OVX+SF300, 300 mg/kg body weight/d) groups. All the rats were fed by gavage for 12 wk. At the end of 12 wk, blood and urine were collected for analysis of bone turnover markers, and bone mineral density (BMD) was measured by micro-computed tomography. The results show that the OVX group (p < 0.05) displayed the highest mean body weight gain. Among the five groups, serum levels of bone alkaline phosphatase (ALP) and urine levels of deoxypyridinoline (DPD) were highest in the OVX group (p < 0.05). Bone ALP levels in the ALEN group were significantly lower than that of the silk-treated groups. On the other hand, DPD levels were not significantly different between the ALEN and silk-fibroin-treated groups (p < 0.05). The trabecular BMD was significantly higher in the ALEN and silk-treated groups compared to the OVX group (p < 0.05). In conclusion, this study showed that silk fibroin has similar effects as alendronate, which is used in osteoporosis medication. Therefore silk fibroin might be a new candidate for the prevention and treatment of osteoporosis in patients.

• Journal of Sericultural and Entomological Science
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• v.51 no.1
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• pp.15-19
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• 2013

Antheraea pernyi silkworm is one of typical wild silkworms, which spins a tawny color cocoon. The cocoon has been used as a resource for textile material due to strong chemical stability and good mechanical properties. In this study, to increase the solubility efficiency of A. pernyi silk fibroin, the composition of dissolution solvent were examined. Calcium chloride tertiary system, normally used for dissolution of Bombyx mori silk fibroin, does not act on A. pernyi silk fibroin. Calcium nitrate system dissolves A. pernyi silk fibroin, and calcium nitrate ethanol system do more easily than calcium nitrate system. Amino acid composition of A. pernyi silk fibroin obtained after dissolution is mainly composed of alanine, glycine, and serine. A. pernyi silk fibroin would be used for non-textile applications near future.

• International Journal of Industrial Entomology and Biomaterials
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• v.35 no.1
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• pp.7-13
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• 2017

In this study, changes in gene expression after administration of silk fibroin fragments ($size{\approx}30kDa$) were evaluated in MG63 cells using a cDNA microarray assay. In addition, the level of alkaline phosphatase (ALP) activity and cellular proliferation in the group administered moderately sized silk fibroin fragments ($size{\approx}30kDa$) (MSF) were compared to those in the group administered smaller silk fibroin fragments (size < 1 kDa) (SSF). The results of the cDNA microarray assay show increased expression of genes that are related to the cell cycle and inflammation. ALP, bone morphogenetic protein-7, bone morphogenetic protein receptor type IA, and runt-related transcription factor 2 exhibited significantly lower expression compared to control cells (fold ratio < 0.5). Relative ALP activity of the $100{\mu}g/mL$ MSF group was significantly lower than that of the SSF group (P < 0.05). Thus, the MSF group showed increased expression of genes associated with cellular proliferation and inflammation but decreased expression of genes associated with osteogenesis.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.541-545
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• 1997

This study was conducted to investigate the effect of cocoon silk fibroin hydrolyzate(CSFH) on shelf-life extension of kimchi. CSFH was added in kimchi in the concentration of 0.3%(w/w), 0.6% and 0.9%. Kimchi with CSFH showed higher pH and lower titratable acidity than control and it was supposed that the growth of lactic acid bacteria was inhibited by CSFH. In model system, for complex lactic acid bacteria, CSFH showes antimicrobial activity.

• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.75-79
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• 2012

Low-melting-temperature agarose gel solution, as a novel porogen was combined with a silk fibroin solution to generate interconnected porous networks. The porosity of the resultant silk fibroin-agarose scaffolds was greater than that of the scaffolds generated with agarose and deionized water. The porosities of silk fibroin scaffolds containing agarose gel at 0.5%, 1.0%, 1.5%, 2.0% [w/v] were 110.9%, 111.7%, 120.9%, and 123.0%, respectively. Lastly, the internal space generated in scaffolds after dissolution of the agarose gel provides a good environment for cell growth and movement within the scaffold.