• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.2
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• pp.228-236
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• 2013

Breast cancer is one of the most common cancers among women worldwide. Recently anticancer agents have been developed using natural substances. To evaluate the anticancer effect of hydrolysates of silk fibroin (HSF), we investigated the effect of HSF on cell viability and apoptosis of a breast cancer cell line, MCF-7, induced through the mitochondrial pathway. The result showed that HSF decreased cell viability in MCF-7 cells in a dose- and time-dependent manner, resulting in an increase in the sub-G1 phase cell population. HSF increased the level of the pro-apoptotic Bax protein and decreased the levels of the anti-apoptotic Bcl-2 protein. In addition, HSF induced apoptosis in MCF-7 cells through a mitochondria-dependent pathway by increasing levels of cytochtome c, and cleavage of PARP. Taken together, these findings suggest that HSF inhibits the proliferation of MCF-7 breast cancer cells through a mitochondria and caspase dependent apoptotic pathway.

• International Journal of Industrial Entomology and Biomaterials
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• v.28 no.2
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• pp.66-70
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• 2014

In order to the feasibility of silk materials as protein delivery system, silk beads incorporated with bovine serum albumin (BSA) were prepared by dropping silk fibroin extract into dope solution composed of ethanol and dichloromethane. Structural and morphological characteristics of silk beads were examined using scanning electron microscopy (SEM), infrared spectrometry, and X-ray diffractometry. Swelling ratio of silk beads was also measured. Release behavior of prototypical protein, BSA, was studied by observing the electropheretic phenomenon and release profile. SEM showed that silk beads are spherical with porous interior structure. Infrared spectrometry and X-ray diffraction confirm that the silk beads have a ${\beta}$-sheet conformation. The swelling capability of silk beads increased with the incorporation of the protein. The protein was released from the beads with slow release following an initial burst release. Therefore, silk beads show promise as materials for encasing protein drugs to be delivered to targets in the human body.

• Macromolecular Research
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• v.17 no.12
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• pp.935-942
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• 2009

Silk is a textile material, as well as one of the oldest biomaterials. However, the recent progress of biomedical science and technology has led to the replacement of silk by various biomaterials based on synthetic polymers. Despite the wide variety of biomaterials available, these materials suffer certain limitations that prevent them from meeting the various demands of the medical field. Therefore, silk continues to attract considerable interest as a promising biomaterial. This paper explains the fundamentals of silk protein, and reviews the many applications of silk biomedical polymers.

• Journal of Life Science
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• v.10 no.4
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• pp.340-346
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• 2000

This study was designed to investigate the effects of silk fibroin(Mw 500) powder (SFP) on oxygen radicals and the scavenger enzymes in brain membranes of rats. Spragu-Dawley(SD) male rats(160${\pm}$10g) were fed basic diet(control group), and experimental diets(SFP-2.5 and SFP-5.0 groups) added 2.5 and 5.0g/kg BW/day for 6 weeks. Hydroxyl radical($.$OH) levels resulted in a decreases(6.6% and 9.7%, 2.8% and 11.9%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group, but were significantly decreased in these membrances of SFP-5.0 group only. Superoxide radical (O2) levels were a slightly decreased (2.0% and 9.1%, respectively) in brain cytosol of SFP-2.5 and SFP-5.0 groups compared with control group. Lipid peroxide(LPO) levels were significantly decreased (12.9% and 21.9%, 13.2% and 22.5%, respectively) in brain mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. Oxidized protein (OP) levels were significantly decreased (16.7% and 15.7%, respectively) in brain microsomes of SFP-2.5 and SFP-5.0 group compared with control group, but significantly difference between in brain mitochondria of these two groups could not be obtained. Mn-SOD activities were remarkably increased (11.2% and 24.2%, respectively) in mitochodria of SFP-2.5 and SFP-5.0 groups. CuZn-SOD activities were effectively increased (7.7% and 19.6%, respectively) in brain cytosol of SFP-2.5 and SFP-5.0 groups, but significant difference between control and SFP-2.5 groups could be not obtained. GSHPx activities were considerably increased (5.3% and 11.7%, respectively) in brain cytosol of SFP-2.0 and SFP-5.0 groups compared with control group. There results suggest that anti-aging effect of silk fibroin may play an effective learning and memory role in a attenuating a oxidative stress and increasing a scavenger enzyme activity in brain membranes.

• Journal of Life Science
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• v.10 no.6
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• pp.577-583
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• 2000

This study was designed to investigate the effect of silk fibroin (Mw 500)power (SFP) on oxygen radicals and their scavenger enzymes in liver membranes of rats. Sprague-Dawley (SD) male rats (160$\pm$10 g) were fed basic diet (control group), and experimental diets (SFP-2.5 and SFP-5.0 groups) added 2.5 and 5.0 g/kg BW/day for 6 weeks. Hydroxyl radical (.OH) levels resulted in a considerable decreases (5.8% and 8.4%, 3.7% and 11.1%, respectively) in liver motochondria and micorsomes of SFP-2.5 and SFP-5.0 groups compared with control group, and $O_2$radical level was remarkably decreased about 15% and 20% in liver cytosol of SFP-2.5 and SFP-5.0 groups compared with control group. Lipid peroxide (LPO) levels were significantly decreased (8.3% and 18.0%, 13.4% and 18.4%, respectively) in liver mitochondria and microsomes of SFP-2.5 and SFP-5.0 groups compared with control group. Oxidized protein (OP) levels were remarkably decreased about 11.6% in liver mitochondria of SFP-5.0 group compared with control group. Mn-SOD activities were remarkably in creased (17.6% and 28.8%, respectively) in mitochondria of SFP-2.5 and SFP-5.0 groups, and Cu/Zn-SOD activities were also effectively in creased (about 14.4%) in liver cytosol of SFP-5.0 groups, but significant difference between GSHPx activity in liver cytosol of these two groups could be not obtained. These results suggest that anti-aging effect of silk fibroin may play an effective anti-aging role in a aattenuating a oxidative stress and increasing a scavenger enzyme activity in liver membranes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.554-562
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• 2007

Ceramide rich intercellular lipid lamellae are thought to be particularly important in maintaining the structural integrity of epidermal barrier. Ceramide is synthesized de novo by serine palmitoyltransferase (SPT) phospholipid intermediates, serine and palmitic acid persist within the stratum corneum. The ceramide which is synthesized is degraded with fatty acid and sphingosine by degradative enzyme ceramidase. The depletion of ceramide in stratum corneum was reported in the atopic dermatitis. As an effort to search for the dietary source for improving the level of ceramide in epidermis, the dietary effects of various-typed silk protein were compared. Seventy male NC/Nga mice, an animal model of atopic dermatitis, were divided into seven groups: group CA as an atopic control with control diet, group S: 1% crude sericin diet, group F: 1% crude fibroin diet, group PS : peptide pattern of sericin(Mw 5000), group PF: peptide pattern of fibroin (Mw 1500), group AS: manufactured the same as amino acid profile of sericin and group AF: manufactured the same as amino acid profile of fibroin. Ten male BALB/c mice were served as group C (control group) control diet. All mice were fed on diet and water ad libitum for 10 weeks. Dry skin condition was established in group CA as ceramide content was decreased. Despite a marked decrease of mRNA and prorein expression of SPT, enzyme do novo synthesis, ceramide content of group S was dramatically increased by inhibiting the mRNA and protein expression of degradative enzyme ceramidase. However, dietary supplementation of crude silk fibroin protein (group F) and in other groups that were supplemented with either amino acid or peptide type of sericin or fibroin did not increase the level of ceramide. Together, our data demonstrate that dietary supplementation of crude sericin is more effective at improving ceramide level in epidemis of NC/Nga mice.

• BMB Reports
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• v.44 no.12
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• pp.787-792
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• 2011

We investigated whether silk fibroin peptide derived from the silkworm, Bombyx mori, could inhibit inflammation and enhance the anti-inflammatory activity of Tat-superoxide dismutase (Tat-SOD), which was previously reported to effectively penetrate various cells and tissues and exert anti-oxidative activity in a mouse model of inflammation. Inflammation was induced by topical treatment of mouse ears with 12-O-tetradecanoylphorbol-13-acetate (TPA). Histological, Western blot, and reverse transcription-polymerase chain reaction data demonstrated that silk fibroin peptide or Tat-SOD alone could suppress elevated levels of cyclooxygenase-2, interleukin-6, interleukin-1beta, and tumor necrosis factor-alpha induced by TPA. Moreover, silk fibroin peptide significantly enhanced the anti-inflammatory activity of Tat-SOD, although it had no influence on in vitro and in vivo transduction of Tat-SOD. Silk fibroin peptide exhibited anti-inflammatory activity in a mice model of inflammation. Therefore, silk fibroin peptide alone or in combination with Tat-SOD might be used as a therapeutic agent for various inflammatory diseases.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.87-92
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• 2012

We constructed the fibroin H-chain expression system to produce Discosoma sp. red fluorescent protein variant2 (DsRed2) in transgenic silkworm cocoon. Fluorescent cocoon could be made by fusing DsRed2 cDNA to the heavy chain gene and injecting it into a silkworm. The DsRed2 fusion protein, each with N- and C-terminal sequences of the fibroin H-chain, was designed to be secreted into the lumen of the posterior silk glands. The expression of the DsRed2/H-chain fusion gene was regulated by the fibroin H-chain promoter. The use of the 3xP3-driven EGFP cDNA as a marker allowed us to rapidly distinguish transgenic silkworms. The EGFP fluorescence became visible in the ocelli and in the central and peripheral nervous system on the seventh day of embryonic development. A mixture of the donor and helper vector was micro-injected into 1,020 Kumokjam, bivoltin silkworm eggs. We obtained 6 broods. The cocoon was displayed strong red fluorescence, proving that the fusion protein was present in the cocoon. Accordingly, we suggest that the DsRed2 fluorescence silk will enable the production of novel biomaterial based on the transgenic silk.

• Journal of Sericultural and Entomological Science
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• v.54 no.1_2
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• pp.6-16
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• 2016

Both mechanical property and biocompatibility of silk protein has been highlighted for decades and lots of studies are trying to use it for a wide variety of applications. Recently, silk-based hydrogel has received great attention in biomedical field such as drug delivery and tissue engineering since silk protein presents a unique hydrogel forming mechanism as well as cyto-compatibility. Silk hydrogels are formed via tremendous physical and chemical techniques and their biomedical applications are extensively explored. In this review, various types and fabrication methods of silk hydrogels are presented and also the recent research trend of silk hydrogel-based applications is summarized.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.10a
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• pp.34-38
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• 2003

The silk fibre Produced by the larvae of the lepidopter of the Bombyx mori species is no doubt one of the most precious raw materials employed in manufacturing textile products. The present report, however, deals with silk not as a traditional textile fibre, but as a starting material fer biomedical applications. In recent years, the unique chemical and mechanical properties of silk have made this protein polymer highly attractive for innovative applications, which mainly focus on the development of devices for biomedical uses. (omitted)