Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Front Bioeng Biotechnol ; 9: 746016, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34926415

RESUMO

Nanofibers as elements for bioscaffolds are pushing the development of tissue engineering. In this study, tussah silk was mechanically disintegrated into nanofibers dispersed in aqueous solution which was cast to generate tussah silk fibroin (TSF) nanofiber mats. The effect of treatment time on the morphology, structure, and mechanical properties of nanofiber mats was examined. SEM indicated decreasing diameter of the nanofiber with shearing time, and the diameter of the nanofiber was 139.7 nm after 30 min treatment. These nanofiber mats exhibited excellent mechanical properties; the breaking strength increased from 26.31 to 72.68 MPa with the decrease of fiber diameter from 196.5 to 139.7 nm. The particulate debris was observed on protease XIV degraded nanofiber mats, and the weight loss was greater than 10% after 30 days in vitro degradation. The cell compatibility experiment confirmed adhesion and spreading of NIH-3T3 cells and enhanced cell proliferation on TSF nanofiber mats compared to that on Bombyx mori silk nanofiber mats. In conclusion, results indicate that TSF nanofiber mats prepared in this study are mechanically robust, slow biodegradable, and biocompatible materials, and have promising application in regenerative medicine.

2.
ACS Appl Mater Interfaces ; 13(33): 40013-40031, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34375080

RESUMO

Flexible and wearable hydrogel strain sensors have attracted tremendous attention for applications in human motion and physiological signal monitoring. However, it is still a great challenge to develop a hydrogel strain sensor with certain mechanical properties and tensile deformation capabilities, which can be in conformal contact with the target organ and also have self-healing properties, self-adhesive capability, biocompatibility, antibacterial properties, high strain sensitivity, and stable electrical performance. In this paper, an ionic conductive hydrogel (named PBST) is rationally designed by proportionally mixing polyvinyl alcohol (PVA), borax, silk fibroin (SF), and tannic acid (TA). SF can not only be a reinforcement to introduce an energy dissipation mechanism into the dynamically cross-linked hydrogel network to stabilize the non-Newtonian behavior of PVA and borax but it can also act as a cross-linking agent to combine with TA to reduce the dissociation of TA on the hydrogel network, improving the mechanical properties and viscoelasticity of the hydrogel. The combination of SF and TA can improve the self-healing ability of the hydrogel and realize the adjustable viscoelasticity of the hydrogel without sacrificing other properties. The obtained hydrogel has excellent stretchability (strain > 1000%) and shows good conformal contact with human skin. When the hydrogel is damaged by external strain, it can rapidly self-repair (mechanical and electrical properties) without external stimuli. It shows adhesiveness and repeatable adhesiveness to different materials (steel, wood, PTFE, glass, iron, and cotton fabric) and biological tissues (pigskin) and is easy to peel off without residue. The obtained PBST conductive hydrogel also has a wide strain-sensing range (>650%) and reliable stability. The hydrogel adhered to the skin surface can monitor large strain movements such as in finger joints, wrist joints, knee joints, and so on and detect swallowing, smiling, facial bulging and calming, and other micro-deformation behaviors. It can also distinguish physical signals such as light smile, big laugh, fast and slow breathing, and deep and shallow breathing. Therefore, the PBST conductive hydrogel material with multiple synergistic functions has great potential as a flexible wearable strain sensor. The PBST hydrogel has antibacterial properties and good biocompatibility at the same time, which provides a safety guarantee for it as a flexible wearable strain sensor. This work is expected to provide a new way for people to develop ideal wearable strain sensors.


Assuntos
Adesivos/química , Materiais Biocompatíveis/química , Fibroínas/química , Hidrogéis/química , Substâncias Viscoelásticas/química , Animais , Antibacterianos/química , Materiais Biocompatíveis/metabolismo , Boratos/química , Sobrevivência Celular/efeitos dos fármacos , Reagentes para Ligações Cruzadas/química , Condutividade Elétrica , Técnicas Eletroquímicas , Desenho de Equipamento/instrumentação , Desenho de Equipamento/métodos , Fibroblastos/citologia , Humanos , Hidrogéis/metabolismo , Camundongos , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Movimento , Álcool de Polivinil/química , Reologia , Pele , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Taninos/química , Dispositivos Eletrônicos Vestíveis , Cicatrização
3.
J Biomater Sci Polym Ed ; 32(15): 1983-1997, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34228588

RESUMO

The current study focuses on the preparation of sericin and silk fibroin blend electrostatic spinning fiber film dressing. The surface morphology of the fiber films was observed by scanning electron microscope, and the hydrophilicity and swelling property of the fiber membrane dressing were analyzed. The biocompatibility of the four dressings was verified by the CCK-8 method and confocal laser microscopy. This experiment showed that the dressing group with the ratio of sericin to silk fibroin of 3:7 had better performance, offering fine and uniform fiber structure, good surface hydrophilicity, high water vapor transmission rate. The swelling rate of it was 822.77 ± 62.78%, and the tensile properties reached the requirements of dressing materials and had an excellent ability to promote cell adhesion and proliferation. This paper provides a possible method for producing of dressing materials with good hydrophilicity and high moisture vapor transmission rate.


Assuntos
Fibroínas , Sericinas , Bandagens
4.
J Mater Chem B ; 9(5): 1238-1258, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33406183

RESUMO

Over the past decade, the hydrogels prepared from silk fibroin have received immense research attention due to the advantages of safe nature, biocompatibility, controllable degradation and capability to combine with other materials. They have broad application prospects in biomedicine and other fields. However, the traditional silk protein hydrogels have a simple network structure and single functionality, thus, leading to poor adaptability towards complex application environments. As a result, the application fields and development have been significantly restricted. However, the development of functional silk protein hydrogels has provided the opportunities to overcome the limitations of the silk protein hydrogels. In recent years, the functional design of the silk protein hydrogels and their potential applications have attracted the attention of scholars worldwide. Nevertheless, a comprehensive review on functional silk protein hydrogels is missing so far. In order to gain an in-depth understanding of the development status of the functional silk protein hydrogels, this article reviews the current status of the preparation, properties and application of the functional silk protein hydrogels. The article first briefly introduces the current cross-linking methods (including physical and chemical cross-linking), principles, advantages and limitations of the silk protein hydrogels. Subsequently, the types of functional silk protein hydrogels (e.g., high strength, injectable, self-healing, adhesive, conductive, environmental stimuli-responsive, 3D printable, etc.) and design principles for functional implementation have been introduced. Next, based on the advantages of the various functional aspects of the silk protein hydrogels, the applications of these hydrogels in the biomedical field (tissue engineering, sustained drug release, wound repair, adhesives, etc.) and bioelectronics are reviewed. Finally, the development prospects and challenges associated with silk protein functional hydrogels have been analyzed. It is hoped that this study will contribute towards the future innovation of the silk protein hydrogels by promoting the rational design of new mechanisms and successful realization of the target applications.


Assuntos
Fibroínas/química , Hidrogéis/síntese química , Engenharia Tecidual , Cicatrização , Animais , Humanos , Hidrogéis/química , Tamanho da Partícula , Propriedades de Superfície
5.
ACS Appl Bio Mater ; 4(2): 1369-1380, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35014488

RESUMO

In this paper, three different mass fractions of sodium carbonate were used for degumming to obtain different degrees of damaged silk fibroin fibers, which were then treated with formic acid to shrink and bond them into 3D scaffolds. The structure and performance of silk fibroin fibers and silk fibroin 3D scaffolds were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, a differential thermal scanner, a universal materials testing machine, and laser confocal microscopy, and the degradation performance was tested by protease degradation. The results showed that an excessive mass fraction of sodium carbonate would cause partial hydrolysis of fibroin fibers, decrease the mechanical properties of fibroin fiber, increase the surface roughness of fibroin fibers, and make mouse embryonic fibroblasts easier to adhere and grow. Silk fibroin fibers were slightly dissolved, shrunk, and dispersed in formic acid. The mass fraction of sodium carbonate can adjust the enzymatic degradation rate of the silk fibroin 3D scaffolds. With the extension of the degradation time, minerals will be deposited on the surface of the scaffolds. The results show that the silk fibroin 3D scaffolds have biocompatibility, mechanical properties, and degradability, which provides a good material for a barrier biofilm in the future.

6.
Carbohydr Polym ; 229: 115515, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826522

RESUMO

Chitosan-silk biocomposite films with nanofibrous structures have been prepared by facile solution casting of chitosan and silk co-dissolved in formic acid. The morphology, structure and mechanical properties of the chitosan-silk biocomposite were characterized by SEM, FTIR, TG-DSC, and mechanical testing. The results demonstrate that the prepared biocomposite films with a chitosan-silk ratio of 3:1 shows a high tensile strength of 97.8 MPa, a strain at break of 10.8% and a Young's modulus of 3.5 GPa, indicating its high strength and elasticity. Also, the preliminary cell culture experiment demonstrated the ideal biocompatibility of chitosan-silk composite films. As a result the superior mechanical properties of this composite film can be attributed to the silk nanofibrils and chitosan self-assembled nanofibers, and the strong hydrogen bonding interaction between the silk nanofibril and chitosan nanofibers. The specific nanostructure, enhanced mechanical properties, and biocompatibility make the biocomposite films a promising material for applications in biomedical devices.


Assuntos
Quitosana/química , Nanofibras/química , Seda/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Proliferação de Células/efeitos dos fármacos , Quitosana/farmacologia , Módulo de Elasticidade , Formiatos/química , Ligação de Hidrogênio , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Ratos , Ratos Sprague-Dawley , Resistência à Tração
7.
ACS Biomater Sci Eng ; 6(4): 2357-2367, 2020 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33455344

RESUMO

Multiple physical cues such as hierarchical microstructures, topography, and stiffness influence cell fate during tissue regeneration. Yet, introducing multiple physical cues to the same biomaterial remains a challenge. Here, a synergistic cross-linking strategy was developed to fabricate protein hydrogels with multiple physical cues based on combinations of two types of silk nanofibers. ß-sheet-rich silk nanofibers (BSNFs) were blended with amorphous silk nanofibers (ASNFs) to form composite nanofiber systems. The composites were transformed into tough hydrogels through horseradish peroxidase (HRP) cross-linking in an electric field, where ASNFs were cross-linked with HRP, while BSNFs were aligned by the electrical field. Anisotropic morphologies and higher stiffness of 120 kPa were achieved. These anisotropic hydrogels induced osteogenic differentiation and the aligned aggregation of stem cells in vitro while also exhibiting osteoinductive capacity in vivo. Improved tissue outcomes with the hydrogels suggest promising applications in bone tissue engineering, as the processing strategy described here provides options to form hydrogels with multiple physical cues.


Assuntos
Fibroínas , Nanofibras , Hidrogéis , Osteogênese , Seda
8.
R Soc Open Sci ; 6(5): 182102, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31218036

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) often induces chronic osteomyelitis and then bone defects. Here, gentamicin-loaded silk/nanosilver composite scaffolds were developed to treat MRSA-induced chronic osteomyelitis. AgNO3 was reduced with silk as a reducing agent in formic acid, forming silver nanoparticles in situ that were distributed uniformly in the composite scaffolds. Superior antibacterial properties against MRSA were achieved for the composite scaffolds, without the compromise of osteogenesis capacity. Then gentamicin was loaded on the scaffolds for better treatment of osteomyelitis. In vivo results showed effective inhibition of the growth of MRSA bacteria, confirming the promising future in the treatment of chronic osteomyelitis.

9.
Exp Ther Med ; 17(1): 123-130, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30651772

RESUMO

Transplantation of olfactory ensheathing cells (OECs) has potential for treating spinal cord and brain injury. However, they are void of an extracellular matrix to support cell growth and migration. Engineering of tissue to mimic the extracellular matrix is a potential solution for neural repair. Tussah silk fibroin (TSF) has good biocompatibility and an Arg-Gly-Asp tripeptide sequence. A small number of studies have assessed the effect of the diameter of TSF nanofibers on cell adhesion, growth and migration. In the present study, TSF nanofibers with a diameter of 400 and 1,200 nm were prepared using electrospinning technology; these were then used as scaffolds for OECs. The structure and morphology of the TSF nanofibers were characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy. An inverted-phase contrast microscope and SEM were used to observe the morphology of OECs on the TSF nanofibers. The effect on the adhesion of the cells was observed following crystal violet staining. The phenotype of the cells and the maximum axon length on the scaffolds were evaluated by immunostaining for nerve growth factor receptor p75. Cell proliferation and viability were assessed by an MTT assay and a Live/Dead reagent kit. The migration efficiency of OECs was observed using live-cell microscopy. The results indicated that a 400-nm TSF fiber scaffold was more conducive to OEC adhesion, growth and migration compared with a 1,200-nm TSF scaffold. The phenotype of the OECs was normal, and no difference in OEC phenotype was observe when comparing those on TSF nanofibers to those on PLL. The present study may provide guidance regarding the preparation of tissue-engineered materials for neural repair.

10.
ACS Biomater Sci Eng ; 5(8): 4077-4088, 2019 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-33448809

RESUMO

Strategies to control neovascularization in damaged tissues remain a key issue in regenerative medicine. Unlike most reported desferrioxamine (DFO)-loaded systems where DFO demonstrates a burst release, here we attain zero-order release behavior above 40 days. This outcome was achieved by blending DFO with silk nanofibers with special hydrophilic-hydrophobic properties. The special silk nanofibers showed strong physical binding capacity with DFO, avoiding chemical cross-linking. Using these new biomaterials in vivo in a rat wound model suggested that the DFO-loaded silk nanofiber hydrogel systems stimulated angiogenesis by the sustained release of DFO, but also facilitated cell migration and tissue ingrowth. These features resulted in faster formation of a blood vessel network in the wounds, as well improved healing when compared to the free DFO system. The DFO-loaded systems are also suitable for the regeneration of other tissues, such as nerve and bone, suggesting universality in the biomedical field.

11.
Integr Biol (Camb) ; 10(7): 406-418, 2018 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-29951652

RESUMO

An in vivo experimental model based on implanting porous biomaterials to study angiogenesis was proposed. In the implanted porous polyvinyl alcohol, three major modes of angiogenesis, sprouting, intussusception and splitting, were found. By electron microscopy and three-dimensional simulation of the angiogenic vessels, we investigated the morphological characteristics of the three modes and paid special attention to the initial morphological difference between intussusception and splitting, and it was confirmed that the endothelial abluminal invagination and intraluminal protrusion are pre-representations of intussusception and splitting, respectively. Based on immunohistochemical analysis of HIF-1α, VEGF and Flt-1 expressions, it was demonstrated that the dominant mode of angiogenesis is related to the local hypoxic condition, and that there is difference in the response of endothelial cells to hypoxia-induced VEGF between sprouting and splitting. Specifically, in the biomaterials implanted for 3 days, the higher expression and gradient of VEGF induced by severe hypoxia in the avascular area caused sprouting of the peripheral capillaries, and in the biomaterial implanted for 9 days, with moderate hypoxia, splitting became a dominant mode. Whether on day 3 or day 9, Flt-1 expression in sprouting endothelia was significantly higher than that in splitting endothelia, which indicates that sprouting is caused by the strong response of endothelial cells to VEGF, while splitting is associated with their weaker response. As a typical experimental example, these results show the effectiveness of the porous biomaterial implantation model for studying angiogenesis, which is expected to become a new general model.


Assuntos
Materiais Biocompatíveis/química , Endotélio/patologia , Neovascularização Fisiológica , Animais , Simulação por Computador , Hipóxia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Imageamento Tridimensional , Imuno-Histoquímica , Masculino , Teste de Materiais , Álcool de Polivinil , Porosidade , Ratos , Ratos Sprague-Dawley , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismo
12.
Mater Sci Eng C Mater Biol Appl ; 59: 185-192, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26652363

RESUMO

Hydrogels prepared by silk fibroin solution have been studied. However, mimicking the nanofibrous structures of extracellular matrix for fabricating biomaterials remains a challenge. Here, a novel two-step method was applied to prepare fibrous hydrogels using regenerated silk fibroin solution containing nanofibrils in a range of tens to hundreds of nanometers. When the gelation process of silk solution occurred, it showed a top-down type gel within 30min. After gelation, silk fibroin fibrous hydrogels exhibited nanofiber network morphology with ß-sheet structure. Moreover, the compressive stress and modulus of fibrous hydrogels were 31.9±2.6 and 2.8±0.8kPa, respectively, which was formed using 2.0wt.% concentration solutions. In addition, fibrous hydrogels supported BMSCs attachment and proliferation over 12days. This study provides important insight in the in vitro processing of silk fibroin into useful new materials.


Assuntos
Células da Medula Óssea/metabolismo , Fibroínas/classificação , Hidrogéis/química , Teste de Materiais , Nanofibras/química , Animais , Células da Medula Óssea/citologia , Masculino , Ratos , Ratos Sprague-Dawley
13.
Int J Pharm ; 494(1): 264-70, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26283278

RESUMO

In the present study, a composite system for the controlled and sustained release of hydrophobic/hydrophilic drugs is described. Composite hydrogels were prepared by blending silk fibroin (SF) with PLA-PEG-PLA copolymer under mild aqueous condition. Aspirin and indomethacin were incorporated into SF/Copolymer hydrogels as two model drugs with different water-solubility. The degradation of composite hydrogels during the drug release was mainly caused by the hydrolysis of copolymers. SF with stable ß-sheet-rich structure was not easily degraded which maintained the mechanical integrity of composite hydrogel. The hydrophobic/hydrophilic interactions of copolymers with model drugs would significantly alter the morphological features of composite hydrogels. Various parameters such as drug load, concentration ratio, and composition of copolymer were considered in vitro drug release. Aspirin as a hydrophilic drug could be controlled release from composite hydrogel at a constant rate for 5 days. Its release was mainly driven by diffusion-based mechanism. Hydrophobic indomethacin could be encapsulated in copolymer nanoparticles distributing in the composite hydrogel. Its sustained release was mainly degradation controlled which could last up to two weeks. SF/Copolymer hydrogel has potential as a useful composite system widely applying for controlled and sustained release of various drugs.


Assuntos
Preparações de Ação Retardada/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Fibroínas/química , Hidrogéis/química , Polímeros/química , Aspirina/química , Interações Hidrofóbicas e Hidrofílicas , Indometacina/química
14.
Mater Sci Eng C Mater Biol Appl ; 51: 287-93, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25842137

RESUMO

Use of organic templates for controlling the growth of inorganic crystals is one of the research topics in biomimetic field. In particular, oriented growth of hydroxyapatite (HAp) in organic fibrous matrix is provided a new view angle to study biomineralization of bone and its potential biomedical applications. The crystallization of HAp in fibrous hydrogels could mimic such biomineralization. In this paper, we report HAp nanorod crystal synthesized successfully by a biomimetic method using calcium chloride and ammonium dihydrogen phosphate as reagents in the presence of silk fibroin/sodium alginate (SF/SA) fibrous hydrogels. The effects of influence factors such as mineral times, pH, and temperature on controlling HAp nanorod crystals are discussed. The elongated HAp nanorods with rectangular column are grown with the increase of mineral times in biomimetic process. By changing pH, HAp nanorod crystals are obtained at alkaline condition in fibrous hydrogels. Moreover, compared to other temperatures, rod-shaped HAp crystals were formed at 20°C. The results imply this to be an effective method for preparing HAp crystals with controllable morphology for bone repair application.


Assuntos
Alginatos/química , Durapatita/síntese química , Fibroínas/química , Hidrogéis/química , Impressão Molecular/métodos , Nanotubos/química , Substitutos Ósseos/síntese química , Cristalização/métodos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Teste de Materiais , Nanofibras/química , Nanofibras/ultraestrutura , Nanotubos/ultraestrutura , Tamanho da Partícula , Propriedades de Superfície
15.
Int J Biol Macromol ; 75: 398-401, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25677178

RESUMO

Regenerated silk fibroin aqueous solution was used to study the crystalline structure of Bombyx mori silk fibroin in vitro. By controlling environmental conditions and concentration of silk fibroin solution, it provided a means for the direct preparing silk I structure and understanding the details of silk fibroin molecules interactions in formation process. In this study, silk fibroin molecules were assembled to form random coil at low concentration of solution and then, as the concentration increases, were converted to silk I at 55% relative humidity (RH). At the same time, the structure of silk fibroin forming below 45 °C was mostly in silk I. A partial ternary phase diagram of temperature-humidity-concentration was constructed based on the results. The results showed silk I structure could be controlled by adjusting the external environmental conditions. The enhanced control over silk I structure, as embodied in phase diagram, could potentially be utilized to understand the molecular chain conformation of silk I in further research work.


Assuntos
Seda/química , Animais , Bombyx/química , Dessecação , Fibroínas/química , Transição de Fase , Conformação Proteica , Temperatura , Fatores de Tempo , Difração de Raios X
16.
ACS Appl Mater Interfaces ; 7(5): 3352-61, 2015 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-25603225

RESUMO

In this study, we report for the first time a novel silk fibroin (SF) nanofibrous films with robust mechanical properties that was fabricated by directly dissolving silk in CaCl2-formic acid solution. CaCl2-FA dissolved silk rapidly at room temperature, and more importantly, it disintegrated silk into nanofibrils instead of separate molecules. The morphology of nanofibrils crucially depended on CaCl2 concentrations, which resulted in different aggregation nanostructure in SF films. The SF film after drawing had maximum elastic modulus, ultimate tensile strength, and strain at break reaching 4 GPa, 106 MPa, and 29%, respectively, in dry state and 206 MPa, 28 MPa, and 188%, respectively, in wet state. Moreover, multiple yielding phenomena and substantially strain-hardening behavior was also observed in the stretched films, indicating the important role played by preparation method in regulating the mechanical properties of SF films. These exceptional and unique mechanical properties were suggested to be caused by preserving silk nanofibril during dissolution and stretching to align these nanofibrils. Furthermore, the SF films exhibit excellent biocompatibility, supporting marrow stromal cells adhesion and proliferation. The film preparation was facile, and the resulting SF films manifested enhanced mechanical properties, unique nanofibrous structures, and good biocompability.


Assuntos
Materiais Biocompatíveis/síntese química , Cloreto de Cálcio/química , Membranas Artificiais , Células-Tronco Mesenquimais/fisiologia , Nanofibras/química , Seda/química , Absorção Fisico-Química , Animais , Proliferação de Células/fisiologia , Sobrevivência Celular/fisiologia , Células Cultivadas , Cristalização/métodos , Módulo de Elasticidade , Masculino , Teste de Materiais , Células-Tronco Mesenquimais/citologia , Nanofibras/ultraestrutura , Tamanho da Partícula , Ratos Sprague-Dawley , Resistência ao Cisalhamento , Seda/ultraestrutura , Soluções , Resistência à Tração , Viscosidade , Molhabilidade
17.
Acta Biomater ; 12: 139-145, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25281787

RESUMO

Silks spun by silkworms and spiders feature outstanding mechanical properties despite being spun under benign conditions. The superior physical properties of silk are closely related to its complicated hierarchical structures constructed from nanoscale building blocks, such as nanocrystals and nanofibrils. Here, we report a novel silk dissolution behavior, which preserved nanofibrils in CaCl2-formic acid solution, that enables spinning of high-quality fibers with a hierarchical structure. This process is characterized by simplicity, high efficiency, low cost, environmental compatibility and large-scale industrialization potential, as well as having utility and potential for the recycling of silk waste and the production of silk-based functional materials.


Assuntos
Cloreto de Cálcio/química , Fibroínas/química , Formiatos/química , Seda/química , Solventes/química , Microscopia Eletrônica de Varredura
18.
Am J Transl Res ; 7(11): 2244-53, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26807172

RESUMO

A novel membrane for guided bone regeneration (GBR), constituting silk fibroin (SF) nanofiber from native silk nanofibril solution, was prepared by electrospinning process. Another barrier membrane, a collagen-type membrane (Bio-Gide®), was used as a comparative sample. Twelve healthy male Sprague-Dawley rats were used in this study. Bilateral round defects were created in the calvarial bone. The bone regenerative efficacy was evaluated in rat calvarial defects. Animals were killed at 4 and 12 weeks. Bone regeneration was analyzed using micro-computed tomography and histological analysis. The SF nanofibrous membrane showed superior results with regard to mechanical tensile properties. At 4 weeks, the bone volume and collagen I positive areas in the SF group were greater than in the Bio-Gide group. At 12 weeks, the defect had completely healed with new bone in both the groups. In conclusion, the SF nanofibrous membranes showed satisfactory mechanical stability, good biocompatibility, slow degradability, and improved new bone regeneration without any adverse inflammatory reactions. Considering the low cost and low risk of disease transmission, the SF nanofibrous membrane is a potential candidate for GBR therapy compared with the widely used collagen membranes.

19.
J Mater Chem B ; 2(17): 2622-2633, 2014 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-24949200

RESUMO

Silk-based porous scaffolds have been used extensively in tissue engineering because of their excellent biocompatibility, tunable biodegradability and robust mechanical properties. Although many silk-based scaffolds have been prepared through freeze-drying, a challenge remains to effectively control porous structures during this process. In the present study silk fibroin with different nanostructures were self-assembled in aqueous solution by repeated drying-dissolving process and then used to improve porous structure formation in lyophilization process. Viscosity, secondary structures and water interactions were also studied to exclude their influence on the formation and control of porous structures. Following nanofiber formation in aqueous solution, silk scaffolds with improved porous structure were directly formed after lyophilization and then stabilized with water or methanol annealing treatments. Compared to silk scaffolds derived from fresh solution, the nanofibrous scaffolds showed significantly better cell compatibility in vitro. Therefore, this nanoscale control of silk offers feasible way to regulate the matrix features including porous structure and nanostructure, which are important in regulating cell and tissue outcomes in tissue engineering and regeneration, and then achieve silk-based scaffolds with improved properties.

20.
Mater Sci Eng C Mater Biol Appl ; 37: 48-53, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24582221

RESUMO

Bombyx mori silk fibroin from the silkworm was firstly found to be soluble in formic acid/hydroxyapatite system. The rheological behavior of silk fibroin solution was significantly influenced by HAp contents in dissolved solution. At the same time, silk fibroin nanofibers were observed in dissolved solution with 103.6±20.4nm in diameter. Moreover, the structure behavior of SF films prepared by formic acid/hydroxyapatite dissolution method was examined. The secondary structure of silk fibroin films was attributed to silk II structure (ß-sheet), indicating that the hydroxyapatite contents in dissolved solution were not significantly affected by the structure of silk fibroin. The X-ray diffraction results exhibited obviously hydroxyapatite crystalline nature existing in silk fibroin films; however, when the hydroxyapatite content was 5.0wt.% in dissolved solution, some hydroxyapatite crystals were converted to calcium hydrogen phosphate dehydrate in silk fibroin dissolution process. This result was also confirmed by Fourier transform infrared analysis and DSC measurement. In addition, silk fibroin films prepared by this dissolution method had higher breaking strength and extension at break. Based on these analyses, an understanding of novel SF dissolution method may provide an additional tool for designing and synthesizing advanced materials with more complex structures, which should be helpful in different fields, including biomaterial applications.


Assuntos
Durapatita/química , Fibroínas/química , Formiatos/química , Animais , Bombyx/química , Bombyx/metabolismo , Nanofibras/química , Solubilidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...