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1.
Int J Mol Sci ; 22(4)2021 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-33546270

RESUMO

This paper explores the structures of exogenous protein molecules that can effectively improve the mechanical properties of silkworm silk. Several transgenic vectors fused with the silkworm fibroin light chain and type 3 repeats in different multiples of the ampullate dragline silk protein 1 (MaSp1) from black widow spider with different lengths of the polyalanine motifs were constructed for this study. Transgenic silkworms were successfully obtained by piggyBac-mediated microinjection. Molecular detection showed that foreign proteins were successfully secreted and contained within the cocoon shells. According to the prediction of PONDR® VSL2 and PONDR® VL-XT, the type 3 repeats and the polyalanine motif of the MaSp1 protein were amorphous. The results of FTIR analysis showed that the content of ß-sheets in the silk of transgenic silkworms engineered with transgenic vectors with additional polyalanine was significantly higher than that of wild-type silkworm silk. Additionally, silk with a higher ß-sheet content had better fracture strength and Young's modulus. The mechanical properties of silk with longer chains of exogenous proteins were improved. In general, our results provide theoretical guidance and technical support for the large-scale production of excellent bionic silk.


Assuntos
Viúva Negra/química , Peptídeos , Seda/química , Sequência de Aminoácidos , Animais , Viúva Negra/metabolismo , Fenômenos Mecânicos , Conformação Proteica em Folha beta , Proteínas Recombinantes , Seda/metabolismo
2.
ACS Appl Mater Interfaces ; 13(7): 8880-8888, 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33576225

RESUMO

We report the unique actuation characteristics of moisture-driven, fully reversible soft biopolymer films fabricated from Bombyx mori silk. The instantaneous actuation is driven by the water vapor induced stress gradient generated across the thickness of the film, and it possesses subsecond response and actuation times. The excellent durability and consistent performance of the film without any noticeable fatigue are established by subjecting it to more than a thousand continuous actuation cycles. The weight-lifting capability of the film is fascinating, where a few tens of micrograms of water generate a colossal force required to lift hundreds of milligrams of weight. Several other potential uses of silk fibroin based soft actuators, such as an intelligent textile layer with the crescent-shaped windows that open on perspiring skin and an autonomous crawler, are also demonstrated. Interestingly, even moisture emanating from the human palm triggers the ultrafast actuation process. These silk films are fabricated using a simple facile solution-casting technique, which can be scaled up with relative ease.


Assuntos
Fibroínas/química , Seda/química , Animais , Bombyx , Tamanho da Partícula , Propriedades de Superfície , Volatilização
3.
Int J Biol Macromol ; 170: 780-792, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33385458

RESUMO

Starch is a benign bio-polymeric material with a diversity of desirable functionalities namely biocompatibility and hydrophilicity features. Besides, corn silk with cellulose-protein structure can be used as an available and clean compound for medical applications. Hence, the advantages of both mentioned biocompatible compounds with potentiality to form hydrogel are considered via their combination. Up to now, there is no report on dealing with starch beside corn silk on polyester fabric in the literatures. Herein, low starch/corn silk dual hydrogel was incorporated into nano ZnO functionalized polyester fabric via a one-step simple method. Imparting flame retardant feature with no dripping, antibacterial/antifungal and self-cleaning activities with the enhanced mechanical characteristics are the advantages of the stated approach in this paper. Presence of dual hydrogel on nano ZnO treated polyester fabric helps to significantly improve the cell viability to 129% because of hydrogel feature. Finally, this paper renders a feasible and clean approach for textile functionalization with respect to the both human health issues and environmental observations.


Assuntos
Nanocompostos/química , Seda/química , Amido/química , Zea mays/química , Óxido de Zinco/química , Antibacterianos/química , Anti-Infecciosos/química , Celulose/química , Humanos , Hidrogéis/química , Poliésteres/química , Tomografia por Emissão de Pósitrons/métodos , Têxteis
4.
Carbohydr Polym ; 253: 117214, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33278979

RESUMO

Nanofibrils derived from natural biopolymers have received extensive interest due to their exceptional mechanical properties and excellent biocompatibility. To fabricate biocompatible chitosan nanocomposites with high mechanical performance, silkworm silks were deconstructed into nanofibrils as structural and mechanical reinforcement of chitosan. After dispersing silk nanofibrils in chitosan solution, a set of nanocomposites, including film, porous scaffold, filament, and nanofibrous sponge, could be fabricated from the blended solutions. Silk nanofibrils could be uniformly dispersed in chitosan solution, and formed multi-dimensional nanocomposites. The nanocomposites exhibited enhanced mechanical strength and thermal stability, and provided a biomimetic nanofibrous structure for biomaterial applications. The enhancement in mechanical properties can be attributed to the interaction between the nanofibril phase and the chitosan matrix. As the polysaccharide/protein bionanocomposites derived from natural biopolymers, these materials offer new opportunities for biomaterial application by virtue of their biocompatibility and biodegradability, as well as enhanced mechanical properties and controllable mesoscopic structure.


Assuntos
Materiais Biocompatíveis/química , Bombyx/metabolismo , Quitosana/química , Nanocompostos/química , Nanofibras/química , Seda/química , Tecidos Suporte/química , Animais , Plásticos Biodegradáveis/química , Porosidade , Temperatura , Resistência à Tração , Engenharia Tecidual/métodos
5.
Methods Mol Biol ; 2174: 73-88, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32813245

RESUMO

In the present work we describe a novel system for the identification of microRNAs (miRNAs) in fluids. The method is based on combined novel 3D microarray technology using silk as scaffold and total internal reflection fluorescence microscopy (TIRFM), which allows for the rapid identification of miRNAs using a portable device.


Assuntos
MicroRNAs/análise , Microscopia de Fluorescência/instrumentação , Microscopia de Fluorescência/métodos , Análise de Sequência com Séries de Oligonucleotídeos/instrumentação , Seda/química , Biomarcadores Tumorais/genética , Desenho de Equipamento , Géis/química , Células HEK293 , Humanos , MicroRNAs/genética , MicroRNAs/isolamento & purificação , Análise de Sequência com Séries de Oligonucleotídeos/métodos
6.
Proc Natl Acad Sci U S A ; 117(25): 14602-14608, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32522869

RESUMO

Bioinspired actuators with stimuli-responsive and deformable properties are being pursued in fields such as artificial tissues, medical devices and diagnostics, and intelligent biosensors. These applications require that actuator systems have biocompatibility, controlled deformability, biodegradability, mechanical durability, and stable reversibility. Herein, we report a bionic actuator system consisting of stimuli-responsive genetically engineered silk-elastin-like protein (SELP) hydrogels and wood-derived cellulose nanofibers (CNFs), which respond to temperature and ionic strength underwater by ecofriendly methods. Programmed site-selective actuation can be predicted and folded into three-dimensional (3D) origami-like shapes. The reversible deformation performance of the SELP/CNF actuators was quantified, and complex spatial transformations of multilayer actuators were demonstrated, including a biomimetic flower design with selective petal movements. Such actuators consisting entirely of biocompatible and biodegradable materials will offer an option toward constructing stimuli-responsive systems for in vivo biomedicine soft robotics and bionic research.


Assuntos
Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Biônica/métodos , Celulose/química , Elastina/química , Elastina/genética , Hidrogéis/química , Conformação Molecular , Nanofibras/química , Engenharia de Proteínas , Robótica/métodos , Seda/química , Seda/genética
7.
Nat Commun ; 11(1): 1630, 2020 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-32242004

RESUMO

The high toughness of natural spider-silk is attributed to their unique ß-sheet secondary structures. However, the preparation of mechanically strong ß-sheet rich materials remains a significant challenge due to challenges involved in processing the polymers/proteins, and managing the assembly of the hydrophobic residues. Inspired by spider-silk, our approach effectively utilizes the superior mechanical toughness and stability afforded by localised ß-sheet domains within an amorphous network. Using a grafting-from polymerisation approach within an amorphous hydrophilic network allows for spatially controlled growth of poly(valine) and poly(valine-r-glycine) as ß-sheet forming polypeptides via N-carboxyanhydride ring opening polymerisation. The resulting continuous ß-sheet nanocrystal network exhibits improved compressive strength and stiffness over the initial network lacking ß-sheets of up to 30 MPa (300 times greater than the initial network) and 6 MPa (100 times greater than the initial network) respectively. The network demonstrates improved resistance to strong acid, base and protein denaturants over 28 days.


Assuntos
Polímeros/química , Seda/química , Animais , Fenômenos Biomecânicos , Interações Hidrofóbicas e Hidrofílicas , Polímeros/síntese química , Conformação Proteica em Folha beta , Aranhas
8.
Sci Rep ; 10(1): 3774, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111964

RESUMO

Hydrogen has the potential to play an important role in decarbonising our energy systems. Crucial to achieving this is the ability to produce clean sources of hydrogen using renewable energy sources. Currently platinum is commonly used as a hydrogen evolution catalyst, however, the scarcity and expense of platinum is driving the need to develop non-platinum-based catalysts. Here we report a protein-based hydrogen evolution catalyst based on a recombinant silk protein from honeybees and a metal macrocycle, cobalt protoporphyrin (CoPPIX). We enhanced the hydrogen evolution activity three fold compared to the unmodified silk protein by varying the coordinating ligands to the metal centre. Finally, to demonstrate the use of our biological catalyst, we built a proton exchange membrane (PEM) water electrolysis cell using CoPPIX-silk as the hydrogen evolution catalyst that is able to produce hydrogen with a 98% Faradaic efficiency. This represents an exciting advance towards allowing protein-based catalysts to be used in electrolysis cells.


Assuntos
Abelhas/química , Hidrogênio/química , Proteínas de Insetos/química , Metaloproteínas/química , Protoporfirinas/química , Seda/química , Animais , Abelhas/genética , Catálise , Proteínas de Insetos/genética , Metaloproteínas/genética , Engenharia de Proteínas , Protoporfirinas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Seda/genética
9.
ACS Appl Mater Interfaces ; 12(10): 12317-12327, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32115937

RESUMO

Peripheral nerve injury is a common serious disease, and the electrical conductivity of nerve scaffolds is of special significance for nerve regeneration. Here, a highly conductive silk knitted composite scaffold was prepared by utilizing hydrogen bonding and electrostatic adsorption between silk amino, graphene (RGO), and polyaniline (PANI). Compared to traditional in situ polymerization of aniline (ANI), the surface of the RGO/PANI/silk conductive knitted scaffold prepared by two-step electrostatic self-assembly had more uniform PANI particles and lower resistance; when GO was 1 g/L and ANI was 0.4, 0.6, or 0.8 mol/L, the RGO/PANI/silk scaffold had better electrical properties when the conductivity was between 0.62 × 10-3 and 1.72 × 10-3 S/cm. The scaffolds had good conductive stability under different physical stresses and good mechanical properties, wherein ultimately the strength, elongation at break, and Young's modulus ranges were 28.07-34.97 MPa, 105.91-109.85%, and 10.2-12.48 MPa, respectively, and so they provided good support. Conductive scaffolds had ordered loops, fiber structure, and large pore sizes between 40 and 70 µm. In summary, RGO/PANI/silk scaffold with good conductivity, pore size distribution, mechanical properties, thermal properties had potential applications in the field of peripheral nerve regeneration.


Assuntos
Nanoestruturas/química , Seda/química , Tecidos Suporte/química , Compostos de Anilina/química , Condutividade Elétrica , Grafite/química , Teste de Materiais , Propriedades de Superfície , Engenharia Tecidual
10.
Drug Deliv ; 27(1): 431-448, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32157919

RESUMO

Fibroin is a dominant silk protein that possesses ideal properties as a biomaterial for drug delivery. Recently, the development of fibroin nanoparticles (FNPs) for various biomedical applications has been extensively studied. Due to their versatility and chemical modifiability, FNPs can encapsulate different types of therapeutic compounds, including small and big molecules, proteins, enzymes, vaccines, and genetic materials. Moreover, FNPs are able to be administered both parenterally and non-parenterally. This review summaries basic information on the silk and fibroin origin and characteristics, followed by the up-to-date data on the FNPs preparation and characterization methods. In addition, their medical applications as a drug delivery system are in-depth explored based on several administrative routes of parenteral, oral, transdermal, ocular, orthopedic, and respiratory. Finally, the challenges and suggested solutions, as well as the future outlooks of these systems are discussed.


Assuntos
Sistemas de Liberação de Medicamentos , Fibroínas/química , Nanopartículas , Animais , Materiais Biocompatíveis/química , Humanos , Seda/química
11.
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
12.
Drug Deliv ; 27(1): 482-490, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32212952

RESUMO

A sodium N-lauryl amino acids (shortly silk sericin surfactant, SSS) is synthesized with lauryl chloride and sericin amino acids recovered from silk industrial waste. The purpose of this study is to explore whether the sericin surfactant can be used as a potential drug delivery carrier. By controlling the proportion of cationic drugs, cytarabine hydrochloride (CH) and anionic SSS, the aggregation behavior, slow release capability and toxicological effects of catanionic aggregates or vesicles, formed through CH and SSS, have been investigated in detail. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and zeta potential analysis showed that the aggregate solution could form a stable vesicle structure when the mass fraction of CH is less than or equal to 0.3. The drug release results showed that the cumulative release rate of the catanionic aggregation solution with CH mass fraction of 0.2 reached a maximum at 18 h, being approximately 9 times greater than that of pure cytarabine. The CH/SSS aggregates had a significant sustained release effect compared with the control group. At the same time, vesicles formed by SSS and CH have better anti-tumor effects compared with the pure drug group. In summary, sericin surfactant from silk industrial waste has a potential use as a drug delivery carrier.


Assuntos
Antimetabólitos Antineoplásicos/administração & dosagem , Citarabina/administração & dosagem , Sistemas de Liberação de Medicamentos , Seda/química , Aminoácidos/química , Antimetabólitos Antineoplásicos/farmacologia , Cátions , Linhagem Celular Tumoral , Citarabina/farmacocinética , Preparações de Ação Retardada , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Humanos , Linfoma/tratamento farmacológico , Sericinas/química , Tensoativos/química
13.
PLoS One ; 15(2): e0228453, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074121

RESUMO

The late 5th instar caterpillar of the cecropia silk moth (Hyalophora cecropia) spins a silken cocoon with a distinct, multilayered architecture. The cocoon construction program, first described by the seminal work of Van der Kloot and Williams, consists of a highly ordered sequence of events. We perform behavioral experiments to re-evaluate the original cecropia work, which hypothesized that the length of silk that passes through the spinneret controls the orderly execution of each of the discrete events of cocoon spinning. We confirm and extend by three-dimensional scanning and quantitative measurements of silk weights that if cocoon construction is interrupted, upon re-spinning, the caterpillar continues the cocoon program from where it left off. We also confirm and extend by quantitative measurements of silk weights that cecropia caterpillars will not bypass any of the sections of the cocoon during the construction process, even if presented with a pre-spun section of a cocoon spun by another caterpillar. Blocking silk output inhibits caterpillars from performing normal spinning behaviors used for cocoon construction. Surprisingly, unblocking silk output 24-hr later did not restart the cocoon construction program, suggesting the involvement of a temporally-defined interval timer. We confirm with surgical reductions of the silk glands that it is the length of silk itself that matters, rather than the total amount of silk extracted by individuals. We used scanning electron microscopy to directly show that either mono- or dual-filament silk (i.e., equal silk lengths but which vary in their total amount of silk extracted) can be used to construct equivalent cocoons of normal size and that contain the relevant layers. We propose that our findings, taken together with the results of prior studies, strongly support the hypothesis that the caterpillar uses a silk "odometer" to measure the length of silk extracted during cocoon construction but does so in a temporally regulated manner. We further postulate that our examination of the anatomy of the silk spinning apparatus and ablating spinneret sensory output provides evidence that silk length measurement occurs upstream of output from the spinneret.


Assuntos
Comportamento Animal/fisiologia , Retroalimentação Sensorial/fisiologia , Manduca/fisiologia , Metamorfose Biológica/fisiologia , Seda/metabolismo , Animais , Ciências Biocomportamentais , Bombyx/anatomia & histologia , Bombyx/fisiologia , Manduca/anatomia & histologia , Microscopia Eletrônica de Varredura , Pupa/fisiologia , Sensação/fisiologia , Seda/análise , Seda/química
14.
Molecules ; 25(4)2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32079339

RESUMO

Polymeric particles are ideal drug delivery systems due to their cellular uptake-relevant size. Microparticles could be developed for direct injection of drug formulations into a diseased site, such as a tumor, allowing for drug retention and slow drug exposure over time through sustained release mechanisms. Bombyx mori silk fibroin has shown promise as a biocompatible biomaterial both in research and the clinic. Silk has been previously used to make particles using an emulsion-based method with poly(vinyl alcohol) (PVA). In this study, polydimethylsiloxane-based microfluidic devices were designed, fabricated, and characterized to produce silk particles through self-association of silk when exposed to PVA. Three main variables resulted in differences in particle size and size distribution, or polydispersity index (PDI). Utilizing a co-flow microfluidic device decreased the PDI of the silk particles as compared to an emulsion-based method (0.13 versus 0.65, respectively). With a flow-focusing microfluidics device, lowering the silk flow rate from 0.80 to 0.06 mL/h resulted in a decrease in the median particle size from 6.8 to 3.0 µm and the PDI from 0.12 to 0.05, respectively. Lastly, decreasing the silk concentration from 12% to 2% resulted in a decrease in the median particle size from 5.6 to 2.8 µm and the PDI from 0.81 to 0.25, respectively. Binding and release of doxorubicin, a cytotoxic drug commonly used for cancer treatment, with the fabricated silk particles was evaluated. Doxorubicin loading in the silk particles was approximately 41 µg/mg; sustained doxorubicin release occurred over 23 days. When the cytotoxicity of the released doxorubicin was tested on KELLY neuroblastoma cells, significant cell death was observed. To demonstrate the potential for internalization of the silk particles, both KELLY and THP-1-derived macrophages were exposed to fluorescently labelled silk particles for up to 24 h. With the macrophages, internalization of the silk particles was observed. Additionally, THP-1 derived macrophages exposure to silk particles increased TNF-α secretion. Overall, this microfluidics-based approach for fabricating silk particles utilizing PVA as a means to induce phase separation and silk self-assembly is a promising approach to control particle size and size distribution. These silk particles may be utilized for a variety of biomedical applications including drug delivery to multiple cell types within a tumor microenvironment.


Assuntos
Microtecnologia/instrumentação , Álcool de Polivinil/química , Reologia/instrumentação , Seda/química , Animais , Bombyx , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Doxorrubicina/química , Humanos , Imageamento Tridimensional , Microfluídica , Peso Molecular , Neuroblastoma/patologia , Seda/farmacologia , Células THP-1 , Fator de Necrose Tumoral alfa/metabolismo
15.
Molecules ; 25(3)2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32046280

RESUMO

Due to its properties, such as biodegradability, low density, excellent biocompatibility and unique mechanics, spider silk has been used as a natural biomaterial for a myriad of applications. First clinical applications of spider silk as suture material go back to the 18th century. Nowadays, since natural production using spiders is limited due to problems with farming spiders, recombinant production of spider silk proteins seems to be the best way to produce material in sufficient quantities. The availability of recombinantly produced spider silk proteins, as well as their good processability has opened the path towards modern biomedical applications. Here, we highlight the research on spider silk-based materials in the field of tissue engineering and summarize various two-dimensional (2D) and three-dimensional (3D) scaffolds made of spider silk. Finally, different applications of spider silk-based materials are reviewed in the field of tissue engineering in vitro and in vivo.


Assuntos
Materiais Biocompatíveis/química , Regeneração/efeitos dos fármacos , Seda/química , Aranhas/química , Engenharia Tecidual/métodos , Animais , Materiais Biocompatíveis/isolamento & purificação , Materiais Biocompatíveis/metabolismo , Materiais Biocompatíveis/farmacologia , Vasos Sanguíneos/citologia , Vasos Sanguíneos/efeitos dos fármacos , Osso e Ossos/citologia , Osso e Ossos/efeitos dos fármacos , Cartilagem/citologia , Cartilagem/efeitos dos fármacos , Técnicas de Cultura de Células , Humanos , Hidrogéis/química , Nervos Periféricos/citologia , Nervos Periféricos/efeitos dos fármacos , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Regeneração/fisiologia , Seda/biossíntese , Seda/isolamento & purificação , Seda/farmacologia , Pele/citologia , Pele/efeitos dos fármacos , Aranhas/fisiologia , Substâncias Viscoelásticas/química
16.
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
17.
Molecules ; 25(1)2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31935972

RESUMO

Silk composites with natural rubber (NR) were prepared by mixing degummed silk and NR latex solutions. A significant enhancement of the mechanical properties was confirmed for silk/NR composites compared to a NR-only product, indicating that silk can be applied as an effective reinforcement for rubber materials. Attenuated total reflection Fourier transform infrared (ATR-FTIR) and wide-angle X-ray diffraction (WAXD) analysis revealed that a ß-sheet structure was formed in the NR matrix by increasing the silk content above 20 wt%. Then, 3,4-dihydroxyphenylalanine (DOPA)-modified silk was also blended with NR to give a DOPA-silk/NR composite, which showed superior mechanical properties to those of the unmodified silk-based composite. Not only the chemical structure but also the dominant secondary structure of silk in the composite was changed after DOPA modification. It was concluded that both the efficient adhesion property of DOPA residue and the secondary structure change improved the compatibility of silk and NR, resulting in the enhanced mechanical properties of the formed composite. The knowledge obtained herein should contribute to the development of the fabrication of novel silk-based elastic materials.


Assuntos
Di-Hidroxifenilalanina/química , Nanocompostos/química , Borracha/química , Seda/química , Técnicas de Química Sintética , Fenômenos Mecânicos , Nanocompostos/ultraestrutura , Reologia , Análise Espectral , Relação Estrutura-Atividade
18.
Nat Commun ; 11(1): 351, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953407

RESUMO

Despite advances in directing the assembly of biomacromolecules into well-defined nanostructures, leveraging pathway complexity of molecular disorder to order transition while bridging materials fabrication from nano- to macroscale remains a challenge. Here, we present templated crystallization of structural proteins to nanofabricate hierarchically structured materials up to centimeter scale, using silk fibroin as an example. The process involves the use of ordered peptide supramolecular assemblies as templates to direct the folding and assembly of silk fibroin into nanofibrillar structures. Silk polymorphs can be engineered by varying the peptide seeds used. Modulation of the relative concentration between silk fibroin and peptide seeds, silk fibroin molecular weight and pH allows control over nanofibrils morphologies and mechanical properties. Finally, facile integration of the bottom-up templated crystallization with emerging top-down techniques enables the generation of macroscopic nanostructured materials with potential applications in information storage/encryption, surface functionalization, and printable three-dimensional constructs of customized architecture and controlled anisotropy.


Assuntos
Fibroínas/química , Nanofibras/química , Nanoestruturas/química , Peptídeos/química , Materiais Biocompatíveis/química , Cristalização/métodos , Cinética , Micelas , Impressão Tridimensional , Dobramento de Proteína , Seda/química , Engenharia Tecidual/métodos
19.
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
20.
ACS Appl Mater Interfaces ; 12(5): 5437-5446, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31917532

RESUMO

A major problem of current biomedical implants is the bacterial colonization and subsequent biofilm formation, which seriously affects their functioning and can lead to serious post-surgical complications. Intensive efforts have been directed toward the development of novel technologies that can prevent bacterial colonization while requiring minimal antibiotics doses. To this end, biocompatible materials with intrinsic antifouling capabilities are in high demand. Silk fibroin, widely employed in biotechnology, represents an interesting candidate. Here, we employ a soft-lithography approach to realize micro- and nanostructured silk fibroin substrates, with different geometries. We show that patterned silk film substrates support mammal cells (HEK-293) adhesion and proliferation, and at the same time, they intrinsically display remarkable antifouling properties. We employ Escherichia coli as representative Gram-negative bacteria, and we observe an up to 66% decrease in the number of bacteria that adhere to patterned silk surfaces as compared to control, flat silk samples. The mechanism leading to the inhibition of biofilm formation critically depends on the microstructure geometry, involving both a steric and a hydrophobic effect. We also couple silk fibroin patterned films to a biocompatible, optically responsive organic semiconductor, and we verify that the antifouling properties are very well preserved. The technology described here is of interest for the next generation of biomedical implants, involving the use of materials with enhanced antibacterial capability, easy processability, high biocompatibility, and prompt availability for coupling with photoimaging and photodetection techniques.


Assuntos
Incrustação Biológica/prevenção & controle , Nanoestruturas/química , Seda/química , Aderência Bacteriana/efeitos dos fármacos , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Materiais Biocompatíveis/farmacologia , Biofilmes/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Células HEK293 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície
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