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Moreno-Tortolero RO, Luo Y, Parmeggiani F, Skaer N, Walker R, Serpell LC, Holland C, Davis SA. Molecular organization of fibroin heavy chain and mechanism of fibre formation in Bombyx mori. Commun Biol 2024; 7:786. [PMID: 38951579 PMCID: PMC11217467 DOI: 10.1038/s42003-024-06474-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 06/19/2024] [Indexed: 07/03/2024] Open
Abstract
Fibroins' transition from liquid to solid is fundamental to spinning and underpins the impressive native properties of silk. Herein, we establish a fibroin heavy chain fold for the Silk-I polymorph, which could be relevant for other similar proteins, and explains mechanistically the liquid-to-solid transition of this silk, driven by pH reduction and flow stress. Combining spectroscopy and modelling we propose that the liquid Silk-I fibroin heavy chain (FibH) from the silkworm, Bombyx mori, adopts a newly reported β-solenoid structure. Similarly, using rheology we propose that FibH N-terminal domain (NTD) templates reversible higher-order oligomerization driven by pH reduction. Our integrated approach bridges the gap in understanding FibH structure and provides insight into the spatial and temporal hierarchical self-assembly across length scales. Our findings elucidate the complex rheological behaviour of Silk-I, solutions and gels, and the observed liquid crystalline textures within the silk gland. We also find that the NTD undergoes hydrolysis during standard regeneration, explaining key differences between native and regenerated silk feedstocks. In general, in this study we emphasize the unique characteristics of native and native-like silks, offering a fresh perspective on our fundamental understanding of silk-fibre production and applications.
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Affiliation(s)
- Rafael O Moreno-Tortolero
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
- Max Planck-Bristol Centre for Minimal Biology, University of Bristol, Bristol, BS8 1TS, UK.
| | - Yijie Luo
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Fabio Parmeggiani
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
- School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Ave, Cardiff, CF10 3NB, UK
| | - Nick Skaer
- Orthox Ltd, Milton Park, 66 Innovation Drive, Abingdon, OX14 4RQ, UK
| | - Robert Walker
- Orthox Ltd, Milton Park, 66 Innovation Drive, Abingdon, OX14 4RQ, UK
| | - Louise C Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Chris Holland
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Sean A Davis
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
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Indrakumar S, Dash TK, Mishra V, Tandon B, Chatterjee K. Silk Fibroin and Its Nanocomposites for Wound Care: A Comprehensive Review. ACS POLYMERS AU 2024; 4:168-188. [PMID: 38882037 PMCID: PMC11177305 DOI: 10.1021/acspolymersau.3c00050] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 06/18/2024]
Abstract
For most individuals, wound healing is a highly organized, straightforward process, wherein the body transitions through different phases in a timely manner. However, there are instances where external intervention becomes necessary to support and facilitate different phases of the body's innate healing mechanism. Furthermore, in developing countries, the cost of the intervention significantly impacts access to treatment options as affordability becomes a determining factor. This is particularly true in cases of long-term wound treatment and management, such as chronic wounds and infections. Silk fibroin (SF) and its nanocomposites have emerged as promising biomaterials with potent wound-healing activity. Driven by this motivation, this Review presents a critical overview of the recent advancements in different aspects of wound care using SF and SF-based nanocomposites. In this context, we explore various formats of hemostats and assess their suitability for different bleeding situations. The subsequent sections discuss the primary causes of nonhealing wounds, i.e., prolonged inflammation and infections. Herein, different treatment strategies to achieve immunomodulatory and antibacterial properties in a wound dressing were reviewed. Despite exhibiting excellent pro-healing properties, few silk-based products reach the market. This Review concludes by highlighting the bottlenecks in translating silk-based products into the market and the prospects for the future.
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Affiliation(s)
- Sushma Indrakumar
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Tapan Kumar Dash
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Vivek Mishra
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Bharat Tandon
- Fibroheal Woundcare Pvt. Ltd., Yelahanka New Town, Bangalore 560064, India
| | - Kaushik Chatterjee
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
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3
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Tan G, Jia T, Qi Z, Lu S. Regenerated Fiber's Ideal Target: Comparable to Natural Fiber. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1834. [PMID: 38673192 PMCID: PMC11050933 DOI: 10.3390/ma17081834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/12/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024]
Abstract
The toughness of silk naturally obtained from spiders and silkworms exceeds that of all other natural and man-made fibers. These insects transform aqueous protein feedstocks into mechanically specialized materials, which represents an engineering phenomenon that has developed over millions of years of natural evolution. Silkworms have become a new research hotspot due to the difficulties in collecting spider silk and other challenges. According to continuous research on the natural spinning process of the silkworm, it is possible to divide the main aspects of bionic spinning into two main segments: the solvent and behavior. This work focuses on the various methods currently used for the spinning of artificial silk fibers to replicate natural silk fibers, providing new insights based on changes in the fiber properties and production processes over time.
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Affiliation(s)
| | | | | | - Shenzhou Lu
- National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, Suzhou 215123, China; (G.T.); (T.J.); (Z.Q.)
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4
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Asakura T, Shimokawatoko H, Nakazawa Y. Characterization and promotion of endothelialization of Bombyx mori silk fibroin functionalized with REDV peptide. Int J Biol Macromol 2024; 261:129746. [PMID: 38302025 DOI: 10.1016/j.ijbiomac.2024.129746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 02/03/2024]
Abstract
In the development of small-diameter vascular grafts, it is crucial to achieve early-stage endothelialization to prevent thrombus formation and intimal hyperplasia. Silk fibroin (SF) from Bombyx mori is commonly used for such grafts. However, there is a need to expedite endothelialization post-implantation. In this study, we functionalized SF with Arg-Glu-Asp-Val (REDV) (SF + REDV) using cyanuric chloride to enhance endothelialization. The immobilization of REDV onto SF was confirmed and the amount of immobilized REDV could be calculated by 1H NMR. Furthermore, the conformational changes in Tyr, Ser, and Ala residues in [3-13C]Tyr- and [3-13C]Ser-SF due to REDV immobilization were monitored using 13C solid-state NMR. The REDV immobilized onto the SF film was found to be exposed on the film's surface, as confirmed by biotin-avidin system. Cell culture experiments, including adhesiveness, proliferation, and extensibility, were conducted using normal human umbilical vein endothelial cells (HUVEC) and normal human aortic smooth muscle cells (HAoSMC) on both SF and SF + REDV films to evaluate the impact of REDV on endothelialization. The results indicated a trend towards promoting HUVEC proliferation while inhibiting HAoSMC proliferation. Therefore, these findings suggest that SF + REDV may be more suitable than SF alone for coating small-diameter SF knitted tubes made of SF threads.
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Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan.
| | - Haruka Shimokawatoko
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Yasumoto Nakazawa
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
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Asakura T, Naito A. Bombyx mori Silk Fibroin and Model Peptides Incorporating Arg-Gly-Asp Motifs and Their Application in Wound Dressings. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18594-18604. [PMID: 38060376 DOI: 10.1021/acs.langmuir.3c02963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Skin plays an important role in protecting the human body from the environment, dehydration, and infection. Burns, wounds, and disease cause the skin to lose its role, but tissue-engineered skin substitutes offer the opportunity to restore skin loss. Silk fibroin from Bombyx mori (SF) has proven to be an excellent wound dressing material. In this study, we aim to develop an excellent wound dressing material by introducing three-residue sequence Arg-Gly-Asp (RGD), which is the most well-known adhesion site of fibronectin, in the films of SF and the model peptide. Its usefulness as a wound dressing material was evaluated both in vitro and in vivo. First, we showed that the flexible structures of the RGD sequence are still maintained in SF with a rigid antiparallel β-sheet structure using NMR in association with excellent wound dressings of SF containing RGD. Then, in in vitro experiments, two types of normal cells derived from human skin, normal human neonatal epidermal keratinocytes and normal human neonatal dermal fibroblasts, were used to evaluate the cell adhesion. On the other hand, in in vivo experiments, the study was conducted using a rat model of a whole skin layer defect wound. The results showed that the high-functionalized SF developed here has the potential to play a significant role in the field of wound dressings.
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Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
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6
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Suzuki Y, Morie S, Okamura H, Asakura T, Naito A. Real-Time Monitoring of the Structural Transition of Bombyx mori Liquid Silk under Pressure by Solid-State NMR. J Am Chem Soc 2023; 145:22925-22933. [PMID: 37828719 DOI: 10.1021/jacs.3c04361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
Silk fibroin is stored in the silk glands of Bombyx mori silkworms as a condensed aqueous solution called liquid silk. It is converted into silk fibers at the silkworm's spinnerets under mechanical forces including shear stress and pressure. However, the detailed mechanism of the structural transition of liquid silk to silk fibers under pressure is not well understood. Magic angle spinning (MAS) in solid-state nuclear magnetic resonance (NMR) can exert pressure on liquid samples in a quantitative manner. In this study, solid-state NMR was used to quantitatively analyze the impact of pressure on the structural transition of liquid silk. A combination of 13C DD-MAS and CP-MAS NMR measurements enabled the conformation and dynamics of the crystalline region of the silk fibroin (both before (Silk Ip) and after (Silk IIp) the structural transition) to be detected in real time with atomic resolution. Spectral analyses proposed that the pressure-induced structural transition from Silk Ip to Silk IIp proceeds by a two-step autocatalytic reaction mechanism. The first reaction step is a nucleation step in which Silk Ip transforms to single lamellar Silk IIp, and the second is a growth step in which the single lamellar Silk IIp acts as a catalyst that reacts with Silk Ip molecules to further form Silk IIp molecules, resulting in stacked lamellar Silk IIp. Furthermore, the rate constant in the second step shows a significant pressure dependence, with an increase in pressure accelerating the formation of large stacked lamellar Silk IIp.
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Affiliation(s)
- Yu Suzuki
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Shota Morie
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Hideyasu Okamura
- Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1, Bunkyo, Fukui-shi, Fukui 9108507, Japan
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16, Nakacho, Koganei, Tokyo 184-8588, Japan
- Graduate School of Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya-ku, Yokohama 240-8501, Japan
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7
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Asakura T, Williamson MP. A review on the structure of Bombyx mori silk fibroin fiber studied using solid-state NMR: An antipolar lamella with an 8-residue repeat. Int J Biol Macromol 2023:125537. [PMID: 37379946 DOI: 10.1016/j.ijbiomac.2023.125537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023]
Abstract
Silk fibroin (SF) fiber from the silkworm Bombyx mori in the Silk II form has been used as an excellent textile fiber for over 5000 years. Recently it has been developed for a range of biomedical applications. Further expansion of these uses builds on the excellent mechanical strength of SF fiber, which derives from its structure. This relationship between strength and SF structure has been studied for over 50 years, but it is still not well understood. In this review, we report the use of solid-state NMR to study stable-isotope labeled SF fiber and stable-isotope labeled peptides including (Ala-Gly)15 and (Ala-Gly-Ser-Gly-Ala-Gly)5 as models of the crystalline fraction. We show that the crystalline fraction is a lamellar structure with a repetitive folding using β-turns every eighth amino acid, and that the sidechains adopt an antipolar arrangement rather than the more well-known polar structure described by Marsh, Corey and Pauling (that is, the Ala methyls in each layer point in opposite directions in alternate strands). The amino acids Ser, Tyr and Val are the next most common in B. mori SF after Gly and Ala, and occur in the crystalline and semi-crystalline regions, probably defining the edges of the crystalline region. Thus, we now have an understanding of the main features of Silk II but there is still a long way to go.
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Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan.
| | - Mike P Williamson
- School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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8
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Asakura T, Nishimura A, Naito A. Stretching-Induced Conformational Transition of [3- 13C]Ser- and [3- 13C]Tyr- Antheraea yamamai Silk Fibroin before Spinning Investigated with 13C Solid-State NMR Spectroscopy. Biomacromolecules 2022; 23:5095-5105. [PMID: 36449573 DOI: 10.1021/acs.biomac.2c00937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The conformational transition of [3-13C]Ser- and [3-13C]Tyr-Antheraea yamamai silk fibroin before spinning induced by stretching was investigated with 13C CP/MAS NMR spectroscopy. The α-helix content of the silk fibroin before stretching was found to be 31.6% based on the Ala and Ser peaks. With increasing stretching ratio, the α-helix and the random coil Ala Cβ peaks decreased gradually, while the β-sheet peak was observed at a stretching ratio of ×5 and increased rapidly upon further stretching. For Ser residue, the α-helix peak decreased monotonically with increasing stretching ratio, but the random coil peak increased slightly till the stretching ratio of ×5 and then decreased. A small β-sheet peak was observed before stretching and then increased rapidly starting from the stretching ratio of ×7. In contrast, a gradual decrease of random coil peak and an increase of β-sheet peak were observed for the Tyr residue. The results of this investigation may be helpful for further studies of fiber formation mechanism in A. yamamai and in the future design of artificial silk materials.
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Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Akio Nishimura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
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9
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Asakura T, Naito A. Structure of silk I (Bombyx mori silk fibroin before spinning) in the dry and hydrated states studied using 13C solid-state NMR spectroscopy. Int J Biol Macromol 2022; 216:282-290. [PMID: 35788005 DOI: 10.1016/j.ijbiomac.2022.06.192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/05/2022]
Abstract
Nowadays, much attention has been paid to Bombyx mori silk fibroin (SF) by many researchers because of excellent physical properties and biocompatibility. These superior properties originate from the structure of SF and therefore, the structural analysis is a key to clarify the superiority. Here we concentrated on silk I structure (SF structure before spinning). We showed that silk I* (the structure of (GAGAGS)n which is a main part of SF) is a repeated type II β-turn, neither α-helix nor random coil, from the conformation-dependent 13C NMR chemical shift data. This conclusion is different from that obtained using IR by many researchers. Next, the formation of silk I* structure was investigated at molecular level using 13C solid-state NMR spectroscopy. Three kinds of 13C INEPT, CP/MAS and DD/MAS NMR spectra were observed for SF, [3-13C] Ser- and [3-13C] Tyr-SF, the crystalline fraction obtained by chymotrypsin treatment of SF and their model peptide with silk I structures in the dry and hydrated states. Especially, the presence of the sequences containing Tyr, (((GX)m1GY)m2 where X = A or V) with random coil conformations adjacent to (GAGAGS)n is an essence to get water-soluble SF and the formation of silk I* structure of (GAGAGS)n.
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Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan.
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Koganei, Tokyo 184-8588, Japan
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10
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Characterization of polyurethane and a silk fibroin-polyurethane composite fiber studied with NMR spectroscopies. Polym J 2022. [DOI: 10.1038/s41428-022-00629-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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Asakura T, Ibe Y, Jono T, Matsuda H, Kuwabara N, Naito A. Structural investigations of polyurethane and
silk‐polyurethane
composite fiber studied by
13
C
solid‐state
NMR
spectroscopy. J Appl Polym Sci 2021. [DOI: 10.1002/app.51178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tetsuo Asakura
- Department of Biotechnology Tokyo University of Agriculture and Technology Koganei Tokyo Japan
| | - Yusuke Ibe
- Polyurethane Research Laboratory Tosoh Corporation Yokkaichi Mie Japan
| | - Takaki Jono
- Polyurethane Research Laboratory Tosoh Corporation Yokkaichi Mie Japan
| | - Hironori Matsuda
- Department of Biotechnology Tokyo University of Agriculture and Technology Koganei Tokyo Japan
| | - Nobuo Kuwabara
- Gunma Sericultural Technology Center Maebashi Gunma Japan
| | - Akira Naito
- Department of Biotechnology Tokyo University of Agriculture and Technology Koganei Tokyo Japan
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12
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Asakura T, Ibe Y, Jono T, Naito A. Structure and dynamics of biodegradable polyurethane-silk fibroin composite materials in the dry and hydrated states studied using 13C solid-state NMR spectroscopy. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2021.109645] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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13
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Structure of Silk I ( Bombyx mori Silk Fibroin before Spinning) -Type II β-Turn, Not α-Helix. Molecules 2021; 26:molecules26123706. [PMID: 34204550 PMCID: PMC8234240 DOI: 10.3390/molecules26123706] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/11/2021] [Accepted: 06/14/2021] [Indexed: 12/04/2022] Open
Abstract
Recently, considerable attention has been paid to Bombyx mori silk fibroin by a range of scientists from polymer chemists to biomaterial researchers because it has excellent physical properties, such as strength, toughness, and biocompatibility. These appealing physical properties originate from the silk fibroin structure, and therefore, structural determinations of silk fibroin before (silk I) and after (silk II) spinning are a key to make wider applications of silk. There are discrepancies about the silk I structural model, i.e., one is type II β-turn structure determined using many solid-state and solution NMR spectroscopies together with selectively stable isotope-labeled model peptides, but another is α-helix or partially α-helix structure speculated using IR and Raman methods. In this review, firstly, the process that led to type II β-turn structure by the authors was introduced in detail. Then the problems in speculating silk I structure by IR and Raman methods were pointed out together with the problem in the assignment of the amide I band in the spectra. It has been emphasized that the conformational analyses of proteins and peptides from IR and Raman studies are not straightforward and should be very careful when the proteins contain β-turn structure using many experimental data by Vass et al. In conclusion, the author emphasized here that silk I structure should be type II β-turn, not α-helix.
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Tanaka T, Abe Y, Cheng CJ, Tanaka R, Naito A, Asakura T. Development of Small-Diameter Elastin-Silk Fibroin Vascular Grafts. Front Bioeng Biotechnol 2021; 8:622220. [PMID: 33585421 PMCID: PMC7874157 DOI: 10.3389/fbioe.2020.622220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022] Open
Abstract
Globally, increasing mortality from cardiovascular disease has become a problem in recent years. Vascular replacement has been used as a treatment for these diseases, but with blood vessels <6 mm in diameter, existing vascular grafts made of synthetic polymers can be occluded by thrombus formation or intimal hyperplasia. Therefore, the development of new artificial vascular grafts is desirable. In this study, we developed an elastin (EL)-silk fibroin (SF) double-raschel knitted vascular graft 1.5 mm in diameter. Water-soluble EL was prepared from insoluble EL by hydrolysis with oxalic acid. Compared to SF, EL was less likely to adhere to platelets, while vascular endothelial cells were three times more likely to adhere. SF artificial blood vessels densely packed with porous EL were fabricated, and these prevented the leakage of blood from the graft during implantation, while the migration of cells after implantation was promoted. Several kinds of 13C solid-state NMR spectra were observed with the EL-SF grafts in dry and hydrated states. It was noted that the EL molecules in the graft had very high mobility in the hydrated state. The EL-SF grafts were implanted into the abdominal aorta of rats to evaluate their patency and remodeling ability. No adverse reactions, such as bleeding at the time of implantation or disconnection of the sutured ends, were observed in the implanted grafts, and all were patent at the time of extraction. In addition, vascular endothelial cells were present on the graft's luminal surface 2 weeks after implantation. Therefore, we conclude that EL-SF artificial vascular grafts may be useful where small-diameter grafts are required.
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Affiliation(s)
- Takashi Tanaka
- Department of Veterinary Surgery, Tokyo University of Agriculture & Technology, Fuchu, Japan
| | - Yasuyuki Abe
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
| | - Chieh-Jen Cheng
- Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan
| | - Ryo Tanaka
- Department of Veterinary Surgery, Tokyo University of Agriculture & Technology, Fuchu, Japan
| | - Akira Naito
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
| | - Tetsuo Asakura
- Department of Biotechnology, Tokyo University of Agriculture & Technology, Koganei, Japan
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