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1.
Nat Commun ; 11(1): 1332, 2020 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-32165612

RESUMO

Compared to transmission systems based on shafts and gears, tendon-driven systems offer a simpler and more dexterous way to transmit actuation force in robotic hands. However, current tendon fibers have low toughness and suffer from large friction, limiting the further development of tendon-driven robotic hands. Here, we report a super tough electro-tendon based on spider silk which has a toughness of 420 MJ/m3 and conductivity of 1,077 S/cm. The electro-tendon, mechanically toughened by single-wall carbon nanotubes (SWCNTs) and electrically enhanced by PEDOT:PSS, can withstand more than 40,000 bending-stretching cycles without changes in conductivity. Because the electro-tendon can simultaneously transmit signals and force from the sensing and actuating systems, we use it to replace the single functional tendon in humanoid robotic hand to perform grasping functions without additional wiring and circuit components. This material is expected to pave the way for the development of robots and various applications in advanced manufacturing and engineering.


Assuntos
Condutividade Elétrica , Seda/química , Aranhas/química , Tendões/fisiologia , Animais , Simulação por Computador , Retroalimentação , Humanos , Teste de Materiais , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Impressão Tridimensional , Robótica , Seda/ultraestrutura
2.
Macromol Rapid Commun ; 41(6): e1900583, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32009279

RESUMO

A unique cuboid spider silk from the outer egg sac of Nephila pilipes, with an unusual square cross-section, is disclosed. The structure-function relationships within this silk are first studied through structural characterization, mechanical measurement, protein conformation, and polypeptide signature of silk proteins. This silk maintains the higher stiffness property of egg sac silks, and also shows a species difference. Environmental response of the mechanical properties within this silk are observed. Synchrotron FTIR microspectroscopy is used to monitor the silk protein conformation in a single natural silk. The ß-sheet structure aligns parallel to the fiber axis with a content of 22% ± 2.6%. The de novo resulting polypeptide from the solid silk fibers are novel, and an abundant polar amino acid insertion is observed. Short polyalanine (An , n ≤ 3), alternating serine and alanine (S/A)X, and alternating glycine and alanine (G/A)X, GGX, and SSX dominates in the resulting de novo polypeptide. This accords with the composition pattern of other egg sac silk proteins, besides the rarely observed GGX. This study broadens the library of egg sac spider silks and provides a new perspective to uncover structure-function relationships in spider silk.


Assuntos
Aminoácidos/química , Fibroínas/química , Peptídeos/química , Seda/química , Alanina/química , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Fibroínas/ultraestrutura , Glicina/química , Teste de Materiais , Conformação Proteica em Folha beta , Serina/química , Seda/ultraestrutura , Aranhas/química , Relação Estrutura-Atividade
3.
Int J Biol Macromol ; 147: 569-575, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31931064

RESUMO

The modulation of structural fibrous protein and polysaccharide biopolymers for the design of biomaterials is still relatively challenging due to the non-trivial nature of the transformation from a biopolymer's native state to a more usable form. To gain insight into the nature of the molecular interaction between silk and cellulose chains, we characterized the structural, thermal and morphological properties of silk-cellulose biocomposites regenerated from the ionic liquid, 1-ethyl-3-methylimidazolium acetate (EMIMAc), as a function of increasing coagulation agent concentrations. We found that the cellulose crystallinity and crystal size are dependent on the coagulation agent, hydrogen peroxide solution. The interpretation of our results suggests that the selection of a proper coagulator is a critical step for controlling the physicochemical properties of protein-polysaccharide biocomposite materials.


Assuntos
Biopolímeros/química , Celulose/química , Escleroproteínas/química , Seda/química , Materiais Biocompatíveis/química , Biopolímeros/genética , Celulose/genética , Celulose/ultraestrutura , Peróxido de Hidrogênio/química , Imidazóis/química , Líquidos Iônicos/química , Polissacarídeos/química , Polissacarídeos/genética , Conformação Proteica em Folha beta/genética , Escleroproteínas/ultraestrutura , Seda/genética , Seda/ultraestrutura
4.
Int J Biol Macromol ; 145: 437-444, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31843611

RESUMO

Orb-weaving spiders produce a diversity of silk fibers throughout their entire lifecycle, and each silk type is given a specific purpose. As a dry fiber material with wet glue, pyriform silks are different from other silk fibers and make the attachment discs which are used for bonding fibers together and attaching dragline silk to other substrates. To date, only two full-length pyriform spidroin 1 (PySp1) gene sequences were identified. Here we present a novel full-length pyriform spidroin 2 (PySp2) from orb-weaving spider, Araneus ventricosus. Although the A. ventricosus PySp2 lack the long linker regions, the central repetitive region of PySp2 is more complex than PySp1 and can be classified into four types of repetitive regions including three novel repetitive sequences and one type of repetitive region that is similar to PySp1 repeats. Prediction of hydrophobicity of A. ventricosus PySp2 reveals the two new repetitive regions display strong hydrophilicity. Analysis of CD spectrum and secondary structure prediction for A. ventricosus PySp2 repeat unit reveal α-helix conformation dominates the repetitive region. Furthermore, recombinant protein-based artificial fibers show the single repeat unit is sufficient for self-assembling into silk fiber.


Assuntos
Fibroínas/química , Conformação Proteica em alfa-Hélice , Seda/química , Sequência de Aminoácidos/genética , Animais , Fibroínas/genética , Fibroínas/ultraestrutura , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Filogenia , Seda/genética , Seda/ultraestrutura , Aranhas/química
5.
Sci Rep ; 9(1): 12649, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477777

RESUMO

Feeding Bombyx mori larvae with chemically-modified diets affects the structure and properties of the resulted silk. Herein, we provide a road map for the use of silkworms as a factory to produce semiconducting/metallic natural silk that can be used in many technological applications such as supercapacitor electrodes. The silkworms were fed with four different types of chemicals; carbon material (graphite), sulfide (MoS2), oxide (TiO2 nanotubes), and a mixture of reactive chemicals (KMnO4/MnCl2). All the fed materials were successfully integrated into the resulted silk. The capacitive performance of the resulted silk was evaluated as self-standing fabric electrodes as well as on glassy carbon substrates. The self-standing silk and the silk@glassy carbon substrate showed a great enhancement in the capacitive performance over that of the unmodified counterparts. The specific capacitance of the self-standing blank silk negative and positive electrodes was enhanced 4 and 5 folds at 10 mV/s, respectively upon the modification with KMnO4/MnCl2 compared to that of the plain silk electrodes.


Assuntos
Bombyx/fisiologia , Têxteis , Dispositivos Eletrônicos Vestíveis , Animais , Eletroquímica , Eletrodos , Comportamento Alimentar , Seda/química , Seda/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Termogravimetria
6.
Sci Rep ; 9(1): 9381, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253818

RESUMO

In recent years, increasing attention has been paid to the origin, transmission and communication of silk. However, this is still an unsolved mystery in archaeology. The identification of silk-producing species, especially silk produced by Bombyx mori (B. mori) and Antheraea pernyi (A. pernyi), is of key significance to address this challenge. In this study, two innovative methods, i.e. immunology and proteomics, were proposed and successfully established for the species identification of silks. ELISAs result demonstrated that the two prepared antibodies exhibited high sensitivity and specificity in distinguishing B. mori and A. pernyi silk. No cross-reactivity with each other was observed. Moreover, biomarkers were obtained for Bombyx and Antheraea through proteomic analysis. It was also confirmed that the biomarkers were suitable for identifying the species that produced a given silk sample. Compared with conventional methods for distinguishing silk species, immunological and proteomics techniques used in tandem can provide intact information and have the potential to provide accurate and reliable information for species identification.


Assuntos
Bombyx/imunologia , Bombyx/metabolismo , Mariposas/imunologia , Mariposas/metabolismo , Proteômica , Seda/análise , Seda/classificação , Animais , Anticorpos/imunologia , Especificidade de Anticorpos/imunologia , Biomarcadores , Reações Cruzadas/imunologia , Bases de Dados Genéticas , Ensaio de Imunoadsorção Enzimática , Proteínas de Insetos , Fenótipo , Proteoma , Proteômica/métodos , Seda/química , Seda/ultraestrutura , Especificidade da Espécie , Análise Espectral
7.
Sci Rep ; 9(1): 5776, 2019 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-30962468

RESUMO

Spider silk and spider orb webs are among the most studied biological materials and structures owing to their outstanding mechanical properties. A key feature that contributes significantly to the robustness and capability to absorb high kinetic energy of spider webs is the presence of junctions connecting different silk threads. Surprisingly, in spite of their fundamental function, the mechanics of spider web junctions have never been reported. Herein, through mechanical characterization and imaging, we show for the first time that spider orb webs host two different types of junction, produced by different silk glands, which have different morphology, and load bearing capability. These differences can be explained in view of the different roles they play in the web, i.e. allowing for a localized damage control or anchoring the whole structure to the surrounding environment.


Assuntos
Fenômenos Mecânicos , Seda/ultraestrutura , Aranhas/fisiologia , Animais , Glândulas Exócrinas/fisiologia , Seda/química
8.
Nat Commun ; 10(1): 1469, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30931923

RESUMO

Global ecological damage has heightened the demand for silk as 'a structural material made from sustainable resources'. Scientists have earnestly searched for stronger and tougher silks. Bagworm silk might be a promising candidate considering its superior capacity to dangle a heavy weight, summed up by the weights of the larva and its house. However, detailed mechanical and structural studies on bagworm silks have been lacking. Herein, we show the superior potential of the silk produced by Japan's largest bagworm, Eumeta variegata. This bagworm silk is extraordinarily strong and tough, and its tensile deformation behaviour is quite elastic. The outstanding mechanical property is the result of a highly ordered hierarchical structure, which remains unchanged until fracture. Our findings demonstrate how the hierarchical structure of silk proteins plays an important role in the mechanical property of silk fibres.


Assuntos
Elasticidade , Sericinas/ultraestrutura , Seda/fisiologia , Resistência à Tração , Animais , Fenômenos Biomecânicos , Japão , Lepidópteros , Teste de Materiais , Mariposas , Sericinas/metabolismo , Seda/ultraestrutura , Estresse Mecânico , Síncrotrons , Raios X
9.
Sci Rep ; 9(1): 6291, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31000733

RESUMO

Tissues are built of cells integrated in an extracellular matrix (ECM) which provides a three-dimensional (3D) microfiber network with specific sites for cell anchorage. By genetic engineering, motifs from the ECM can be functionally fused to recombinant silk proteins. Such a silk protein, FN-silk, which harbours a motif from fibronectin, has the ability to self-assemble into networks of microfibers under physiological-like conditions. Herein we describe a method by which mammalian cells are added to the silk solution before assembly, and thereby get uniformly integrated between the formed microfibers. In the resulting 3D scaffold, the cells are highly proliferative and spread out more efficiently than when encapsulated in a hydrogel. Elongated cells containing filamentous actin and defined focal adhesion points confirm proper cell attachment to the FN-silk. The cells remain viable in culture for at least 90 days. The method is also scalable to macro-sized 3D cultures. Silk microfibers formed in a bundle with integrated cells are both strong and extendable, with mechanical properties similar to that of artery walls. The described method enables differentiation of stem cells in 3D as well as facile co-culture of several different cell types. We show that inclusion of endothelial cells leads to the formation of vessel-like structures throughout the tissue constructs. Hence, silk-assembly in presence of cells constitutes a viable option for 3D culture of cells integrated in a ECM-like network, with potential as base for engineering of functional tissue.


Assuntos
Matriz Extracelular/genética , Fibronectinas/genética , Proteínas Recombinantes/genética , Seda/genética , Animais , Adesão Celular/genética , Técnicas de Cultura de Células , Diferenciação Celular/genética , Proliferação de Células/genética , Matriz Extracelular/ultraestrutura , Fibronectinas/química , Fibronectinas/ultraestrutura , Engenharia Genética , Humanos , Hidrogéis/química , Proteínas Recombinantes/ultraestrutura , Seda/ultraestrutura , Células-Tronco/metabolismo
10.
Nanotechnology ; 30(29): 295101, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30917342

RESUMO

In this study, an antibacterial degummed silk fiber (ADSF)/nano-hydroxyapatite/polylactic acid (ADSF/nHA/PLA) porous scaffold with antibacterial properties was prepared by using degummed silk fiber (DSF) loaded with silver nano-particles (Ag NPs) as a reinforcing material. In the experiment, ADSF and nHA were used as the main variables to investigate the effect of the change of the composition ratio on the performance of the composite scaffold, and a composite scaffold with excellent performance was obtained. Firstly, the DSFs were treated with dopamine (DA) and the silver ions were reduced to Ag NPs using the strong reducibility of polydopamine (PDA) to prepare ADSF loaded with Ag NPs. Finally, ADSF/nHA/PLA composite scaffolds with antibacterial properties were prepared using ADSF as a reinforcing material. In addition, samples were found to have good mineralization capacity in in vitro mineralization experiments. At the same time, in cell culture and antibacterial experiments, ADSF/nHA/PLA scaffolds were found to have good bioactivity, biocompatibility and antibacterial properties. All the results showed that the Ag NPs loaded DSF improved the performance of the nHA/PLA composite scaffold, while the ADSF/nHA/PLA had good bioactivity and antibacterial properties, making the antibacterial ADSF/nHA/PLA composite scaffold has a great potential for bone tissue engineering.


Assuntos
Antibacterianos/síntese química , Nanopartículas Metálicas/química , Seda/química , Tecidos Suporte/química , Animais , Antibacterianos/farmacologia , Células Cultivadas , Força Compressiva , Dopamina/química , Durapatita/química , Escherichia coli/efeitos dos fármacos , Indóis/química , Nanopartículas Metálicas/ultraestrutura , Camundongos , Poliésteres/química , Polímeros/química , Porosidade , Seda/ultraestrutura , Staphylococcus aureus/efeitos dos fármacos , Engenharia Tecidual/métodos
11.
J Morphol ; 280(4): 534-543, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30791126

RESUMO

Spiders attach silken threads to substrates by means of glue-coated nanofibers (piriform silk), spun into disc-like structures. The organization and ultrastructure of this nano-composite silk are largely unknown, despite their implications for the biomechanical function and material properties of thread anchorages. In this work, the ultrastructure of silken attachment discs was studied in representatives of four spider families with Transmission Electron Microscopy to facilitate a mechanistic understanding of piriform silk function across spiders. Based on previous findings from comparative studies of piriform silk gland morphology, we hypothesized that the fibre-glue proportion of piriform silk differs in different spiders, while the composition of fibre and glue fractions is consistent. Results confirmed large differences in the relative proportion of glue with low amounts in the orb weaver Nephila senegalensis (Araneidae) and the hunting spider Cupiennius salei (Ctenidae), larger amounts in the cobweb spider Parasteatoda tepidariorum (Theridiidae) and a complete reduction of the fibrous component in the haplogyne spider Pholcus phalangioides (Pholcidae). We rejected our hypothesis that glue ultrastructure is consistent. The glue is a colloid with polymeric and fluid fractions that strongly differ in proportions and assembly. We further confirmed that in all species studied both dragline and piriform silk fibres do not make contact with the environmental substrate. Instead, adhesion is established by a thin dense skin layer of the piriform glue. These results advance our understanding of piriform silk function and the interspecific variation of its properties, which is significant for spider biology, web function and the bioengineering of silk.


Assuntos
Seda/ultraestrutura , Aranhas/anatomia & histologia , Aranhas/ultraestrutura , Animais , Processamento de Imagem Assistida por Computador , Aranhas/citologia
12.
Sci Rep ; 9(1): 2398, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30787337

RESUMO

The conditions required for the emergence of supercontraction in regenerated silkworm (Bombyx mori) silk fibers are assessed through an experimental approach that combines the spinning of regenerated fibers with controlled properties and their characterization by 13C solid-state nuclear magnetic resonance (NMR). Both supercontracting and non-supercontracting regenerated fibers are produced using the straining flow spinning (SFS) technique from 13C labeled cocoons. The short-range microstructure of the fibers is assessed through 13C CP/MAS in air and 13C DD/MAS in water, and the main microstructural features are identified and quantified. The mechanical properties of the regenerated fibers and their microstructures are compared with those of natural silkworm silk. The combined analysis highlights two possible key elements as responsible for the emergence of supercontraction: (1) the existence of an upper and a lower limit of the amorphous phase compatible with supercontraction, and (2) the existence of two ordered phases, ß-sheet A and B, which correspond to different packing arrangements of the protein chains.


Assuntos
Bombyx/química , Fibroínas/química , Regeneração/fisiologia , Seda/química , Animais , Bombyx/ultraestrutura , Fibroínas/ultraestrutura , Ressonância Magnética Nuclear Biomolecular , Regeneração/genética , Seda/ultraestrutura , Resistência à Tração , Água/química
13.
Small ; 15(12): e1805294, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30756524

RESUMO

Spider silks are desirable materials with mechanical properties superior to most synthetic materials coupled with biodegradability and biocompatibility. In order to replicate natural silk properties using recombinant spider silk proteins (spidroins) and wet-spinning methods, the focus to date has typically been on modifying protein sequence, protein size, and spinning conditions. Here, an alternative approach is demonstrated. Namely, using the same ≈57 kDa recombinant aciniform silk protein with a consistent wet-spinning protocol, fiber mechanical properties are shown to significantly differ as a function of the solvent used to dissolve the protein at high concentration (the "spinning dope" solution). A fluorinated acid/alcohol/water dope leads to drastic improvement in fibrillar extensibility and, correspondingly, toughness compared to fibers produced using a previously developed fluorinated alcohol/water dope. To understand the underlying cause for these mechanical differences, morphology and structure of the two classes of silk fiber are compared, with features tracing back to dope-state protein structuring and preassembly. Specifically, distinct classes of spidroin nanoparticles appear to form in each dope prior to fiber spinning and these preassembled states are, in turn, linked to fiber morphology, structure, and mechanical properties. Tailoring of dope-state spidroin nanoparticle assembly, thus, appears a promising strategy to modulate fibrillar silk properties.


Assuntos
Proteínas Recombinantes/química , Seda/química , Animais , Anisotropia , Difusão Dinâmica da Luz , Nanopartículas/química , Estrutura Secundária de Proteína , Espectroscopia de Prótons por Ressonância Magnética , Seda/ultraestrutura , Solventes/química , Análise Espectral Raman , Aranhas , Estresse Mecânico , Viscosidade
14.
Physiol Biochem Zool ; 92(1): 115-124, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30601104

RESUMO

Coexistence of organisms and pathogens has resulted in the evolution of efficient antimicrobial defense, especially at the embryonic stage. This investigation aimed to substantiate the hypothesis that the layers of silk in a spider cocoon play a role in the immunity of the embryos against microorganisms present in the external environment. A two-step interdisciplinary attempt has been made. First, the eggs and empty cocoons of the spider Parasteatoda tepidariorum were incubated on lysogeny broth agar media for 3 d. In the samples of eggs, no growth of bacteria was detected. This indicated that the eggs inside cocoons were sterile. Therefore, in the second step, the cocoons and egg surface were analyzed using SEM, TEM, and LM. The obtained images demonstrated that both inner and outer layers of the silk are built of threads of the same diameter, set in an irregular manner, and randomly clustered into groups. The threads in the outer layer were packed more densely than in the inner one. TEM analysis revealed threads of two types of fibrils and their arrangement. The resultant thread tangle of the cocoon, possibly correlated with the ultrastructure of the fibers, seems to be an example of a structure-function relationship playing a crucial ecoimmunological role in spider embryonic development.


Assuntos
Bactérias/crescimento & desenvolvimento , Seda/ultraestrutura , Aranhas/embriologia , Animais , Embrião não Mamífero/microbiologia , Aranhas/microbiologia , Aranhas/ultraestrutura
15.
Sci Rep ; 8(1): 15956, 2018 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-30374029

RESUMO

Spider dragline silk is a remarkable material that shows excellent mechanical properties, diverse applications, biocompatibility and biodegradability. Transgenic silkworm technology was used to obtain four types of chimeric silkworm/spider (termed composite) silk fibres, including different lengths of recombinant Major ampullate Spidroin1 (re-MaSp1) or recombinant Major ampullate Spidroin2 (re-MaSp2) from the black widow spider, Latrodectus hesperus. The results showed that the overall mechanical properties of composite silk fibres improved as the re-MaSp1 chain length increased, and there were significant linear relationships between the mechanical properties and the re-MaSp1 chain length (p < 0.01). Additionally, a stronger tensile strength was observed for the composite silk fibres that included re-MaSp1, which only contained one type of repetitive motif, (GA)n/An, to provide tensile strength, compared with the silk fibres that includedre-MaSp2, which has the same protein chain length as re-MaSp1 but contains multiple types of repetitive motifs, GPGXX and (GA)n/An. Therefore, the results indicated that the nature of various repetitive motifs in the primary structure played an important role in imparting excellent mechanical properties to the protein-based silk fibres. A silk protein with a single type of repetitive motif and sufficiently long chains was determined to be an additional indispensable factor. Thus, this study forms a foundation for designing and optimizing the structure of re-silk protein using a heterologous expression system.


Assuntos
Viúva Negra/genética , Bombyx/genética , Fibroínas/química , Seda/química , Animais , Animais Geneticamente Modificados , Bombyx/metabolismo , Cromossomos Artificiais Bacterianos , Éxons/genética , Fibroínas/genética , Genes de Insetos , Genes Sintéticos , Vetores Genéticos , Genótipo , Microscopia Eletrônica de Varredura , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Sequências Repetitivas de Aminoácidos , Seda/ultraestrutura , Estresse Mecânico , Resistência à Tração
16.
Proc Natl Acad Sci U S A ; 115(45): 11507-11512, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30348773

RESUMO

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable-properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.


Assuntos
Viúva Negra/química , Fibroínas/ultraestrutura , Nanopartículas/química , Seda/ultraestrutura , Animais , Viúva Negra/fisiologia , Fibroínas/biossíntese , Fibroínas/química , Cristais Líquidos/química , Cristais Líquidos/ultraestrutura , Micelas , Microdissecção , Nanopartículas/ultraestrutura , Transição de Fase , Seda/biossíntese , Seda/química
17.
Chem Soc Rev ; 47(17): 6486-6504, 2018 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-29938722

RESUMO

Silks are natural fibrous protein polymers that are spun by silkworms and spiders. Among silk variants, there has been increasing interest devoted to the silkworm silk of B. mori, due to its availability in large quantities along with its unique material properties. Silk fibroin can be extracted from the cocoons of the B. mori silkworm and combined synergistically with other biomaterials to form biopolymer composites. With the development of recombinant DNA technology, silks can also be rationally designed and synthesized via genetic control. Silk proteins can be processed in aqueous environments into various material formats including films, sponges, electrospun mats and hydrogels. The versatility and sustainability of silk-based materials provides an impressive toolbox for tailoring materials to meet specific applications via eco-friendly approaches. Historically, silkworm silk has been used by the textile industry for thousands of years due to its excellent physical properties, such as lightweight, high mechanical strength, flexibility, and luster. Recently, due to these properties, along with its biocompatibility, biodegradability and non-immunogenicity, silkworm silk has become a candidate for biomedical utility. Further, the FDA has approved silk medical devices for sutures and as a support structure during reconstructive surgery. With increasing needs for implantable and degradable devices, silkworm silk has attracted interest for electronics, photonics for implantable yet degradable medical devices, along with a broader range of utility in different device applications. This Tutorial review summarizes and highlights recent advances in the use of silk-based materials in bio-nanotechnology, with a focus on the fabrication and functionalization methods for in vitro and in vivo applications in the field of tissue engineering, degradable devices and controlled release systems.


Assuntos
Materiais Biocompatíveis/química , Bioengenharia/métodos , Bombyx/química , Nanoestruturas/química , Nanotecnologia/métodos , Seda/química , Animais , Materiais Biocompatíveis/metabolismo , Bioengenharia/instrumentação , Bombyx/genética , Bombyx/metabolismo , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Desenho de Equipamento , Engenharia Genética/instrumentação , Engenharia Genética/métodos , Humanos , Nanoestruturas/ultraestrutura , Nanotecnologia/instrumentação , Seda/genética , Seda/metabolismo , Seda/ultraestrutura , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
18.
Biomaterials ; 178: 122-133, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29920404

RESUMO

In the bone marrow, the interaction of progenitor cells with the vasculature is fundamental for the release of blood cells into circulation. Silk fibroin, derived from Bombyx mori silkworm cocoons, is a promising protein biomaterial for bone marrow tissue engineering, because of its tunable architecture and mechanical properties, the capacity to incorporate labile compounds without loss of bioactivity and the demonstrated ability to support blood cell formation without premature activation. In this study, we fabricated a custom perfusion chamber to contain a multi-channel lyophilized silk sponge mimicking the vascular network in the bone marrow niche. The perfusion system consisted in an inlet and an outlet and 2 splitters that allowed funneling flow in each single channel of the silk sponge. Computational Fluid Dynamic analysis demonstrated that this design permitted confined flow inside the vascular channels. The silk channeled sponge supported efficient platelet release from megakaryocytes (Mks). After seeding, the Mks localized along SDF-1α functionalized vascular channels in the sponge. Perfusion of the channels allowed the recovery of functional platelets as demonstrated by increased PAC-1 binding upon thrombin stimulation. Further, increasing the number of channels in the silk sponge resulted in a proportional increase in the numbers of platelets recovered, suggesting applicability to scale-up for platelet production. In conclusion, we have developed a scalable system consisting of a multi-channeled silk sponge incorporated in a perfusion chamber that can provide useful technology for functional platelet production ex vivo.


Assuntos
Plaquetas/citologia , Medula Óssea/irrigação sanguínea , Hidrodinâmica , Seda/farmacologia , Tecidos Suporte/química , Animais , Reatores Biológicos , Plaquetas/efeitos dos fármacos , Bombyx , Medula Óssea/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Humanos , Megacariócitos/citologia , Megacariócitos/efeitos dos fármacos , Reologia , Seda/ultraestrutura
19.
Nat Commun ; 9(1): 452, 2018 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-29386508

RESUMO

Light in biological media is known as freely diffusing because interference is negligible. Here, we show Anderson light localization in quasi-two-dimensional protein nanostructures produced by silkworms (Bombyx mori). For transmission channels in native silk, the light flux is governed by a few localized modes. Relative spatial fluctuations in transmission quantities are proximal to the Anderson regime. The sizes of passive cavities (smaller than a single fibre) and the statistics of modes (decomposed from excitation at the gain-loss equilibrium) differentiate silk from other diffusive structures sharing microscopic morphological similarity. Because the strong reflectivity from Anderson localization is combined with the high emissivity of the biomolecules in infra-red radiation, silk radiates heat more than it absorbs for passive cooling. This collective evidence explains how a silkworm designs a nanoarchitectured optical window of resonant tunnelling in the physically closed structures, while suppressing most of transmission in the visible spectrum and emitting thermal radiation.


Assuntos
Nanofibras/efeitos da radiação , Seda/efeitos da radiação , Animais , Bombyx , Luz , Luminescência , Seda/ultraestrutura
20.
Lasers Med Sci ; 33(4): 785-794, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29250712

RESUMO

Low-level laser therapy (LLLT) has been used for more than 30 years to heal wounds. In recent years, LLLT or photostimulation has been indicated as an effective tool for regenerative and dental medicine by using monochromatic light. The aim of this study is to indicate the usability of plasma arc light source for bone regeneration. This is why we used polychromatic light source providing effective wavelengths in the range of 590-1500 nm for cellular response and investigated photostimulation effects on osteogenic differentiation of human mesenchymal stem cells (hMSCs) seeded on 3D silk scaffolds. Cellular responses were examined by using cell culture methods in terms of proliferation, differentiation, and morphological analyses. The results showed that photostimulation with a polychromatic light source (applied for 5 min from the 3rd day after seeding up to the 28th day in 2-day intervals with 92-mW/cm2 power from 10-cm distance to the cells) enhanced osteogenic differentiation of hMSCs according to higher alkaline phosphatase (ALP) activity, collagen and calcium content, osteogenic gene expressions, and matrix mineralization. In conclusion, we suggest that the plasma arc light source that was used here has a great potential for bone regeneration.


Assuntos
Diferenciação Celular/efeitos da radiação , Células-Tronco Mesenquimais/fisiologia , Seda , Tecidos Suporte , Fosfatase Alcalina/metabolismo , Regeneração Óssea , Cálcio/metabolismo , Técnicas de Cultura de Células , Proliferação de Células , Células Cultivadas , Colágeno/metabolismo , Humanos , Raios Infravermelhos , Terapia com Luz de Baixa Intensidade , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos da radiação , Osteogênese/fisiologia , Seda/ultraestrutura
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