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1.
ACS Appl Bio Mater ; 7(2): 853-862, 2024 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-38270977

RESUMO

In biosensor development, silk fibroin is advantageous for providing transparent, flexible, chemically/mechanically stable, biocompatible, and sustainable substrates, where the biorecognition element remains functional for long time periods. These properties are employed here in the production of point-of-care biosensors for resource-limited regions, which are able to display glucose levels without the need for external instrumentation. These biosensors are produced by photopatterning silk films doped with the enzymes glucose oxidase and peroxidase and photoelectrochromic molecules from the dithienylethene family acting as colorimetric mediators of the enzymatic reaction. The photopatterning results from the photoisomerization of dithienylethene molecules in the silk film from its initial uncolored opened form to its pink closed one. The photoisomerization is dose-dependent, and colored patterns with increasing color intensities are obtained by increasing either the irradiation time or the light intensity. In the presence of glucose, the enzymatic cascade reaction is activated, and peroxidase selectively returns closed dithienylethene molecules to their initial uncolored state. Color disappearance in the silk film is proportional to glucose concentration and used to distinguish between hypoglycemic (below 4 mM), normoglycemic (4-6 mM), and hyperglycemic levels (above 6 mM) by visual inspection. After the measurement, the biosensor can be regenerated by irradiation with UV light, enabling up to five measurement cycles. The coupling of peroxidase activity to other oxidoreductases opens the possibility to produce long-life reusable smart biosensors for other analytes such as lactate, cholesterol, or ethanol.


Assuntos
Técnicas Biossensoriais , Seda , Seda/química , Colorimetria/métodos , Peroxidases , Técnicas Biossensoriais/métodos , Peroxidase , Glucose
2.
Dent Mater ; 40(3): 431-440, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38114344

RESUMO

OBJECTIVES: The current in vitro study aims to evaluate silk fibroin with and without the addition of graphene as a potential scaffold material for regenerative endodontics. MATERIAL AND METHODS: Silk fibroin (SF), Silk fibroin/graphene oxide (SF/GO) and silk fibroin coated with reduced graphene oxide (SF/rGO) scaffolds were prepared (n = 30). The microarchitectures and mechanical properties of scaffolds were evaluated using field emission scanning electron microscopy (FESEM), pore size and water uptake, attenuated total reflectance fourier transformed infrared spectroscopy (ATR-FTIR), Raman spectroscopy and mechanical compression tests. Next, the study analyzed the influence of these scaffolds on human dental pulp stem cell (hDPSC) viability, apoptosis or necrosis, cell adhesion, odontogenic differentiation marker expression and mineralized matrix deposition. The data were analyzed with ANOVA complemented with the Tukey post-hoc test (p < 0.005). RESULTS: SEM analysis revealed abundant pores with a size greater than 50 nm on the surface of tested scaffolds, primarily between 50 nm and 600 µm. The average value of water uptake obtained in pure fibroin scaffolds was statistically higher than that of those containing GO or rGO (p < 0.05). ATR-FTIR evidenced that the secondary structures did not present differences between pure fibroin and fibroin coated with graphene oxide, with a similar infrared spectrum in all tested scaffolds. Raman spectroscopy showed a greater number of defects in the links in SF/rGO scaffolds due to the reduction of graphene. In addition, adequate mechanical properties were exhibited by the tested scaffolds. Regarding biological properties, hDPSCs attached to scaffolds were capable of proliferating at a rate similar to the control, without affecting their viability over time. A significant upregulation of ALP, ON and DSPP markers was observed with SF/rGO and SF/GO groups. Finally, SF/GO and SF/rGO promoted a significantly higher mineralization than the control at 21 days. SIGNIFICANCE: Data obtained suggested that SF/GO and SF/rGO scaffolds promote hDPSC differentiation at a genetic level, increasing the expression of key osteo/odontogenic markers, and supports the mineralization of the extracellular matrix. However, results from this study are to be interpreted with caution, requiring further in vivo studies to confirm the potential of these scaffolds.


Assuntos
Fibroínas , Grafite , Humanos , Fibroínas/química , Alicerces Teciduais/química , Engenharia Tecidual/métodos , Grafite/química , Polpa Dentária , Diferenciação Celular , Água , Proliferação de Células , Células-Tronco
3.
Minerva Urol Nephrol ; 75(2): 194-202, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36999837

RESUMO

BACKGROUND: A major limitation in the treatment of upper urinary tract urothelial carcinoma is the limited use of adjuvant therapy due to the drawbacks of current techniques for intracavitary instillation. The aim was to assess, in a large animal model, a biodegradable ureteral stent coated with silk fibroin for mitomycin release, i.e. BraidStent-SF-MMC. METHODS: A total of 14 female pigs with a solitary kidney underwent initial urinalysis, blood chemistry, nephrosonographic, and contrast fluoroscopy assessment of the urinary tract. Later, the BraidStent-SF-MMC was placed retrogradely to assess the mitomycin urine concentration from 0-48 hours. Follow-up was performed weekly until complete stent degradation to assess the macroscopic and microscopic changes in the urinary tract, stent complications. RESULTS: The drug eluting stent released mitomycin for the first 12 h. The main complication was the release of obstructive ureteral coating fragments during the first to third week in 28.5 and 7.1% of animals, respectively, related to urinary pH<7.0, which destabilized the stent coating. Another complication was ureteral strictures between the fourth and sixth week in 21%. The stents were completely degraded by 6-7 weeks. There were no stent-related systemic toxic effects. The success rate was 67.5% and the complication rate was 25.7%. CONCLUSIONS: For the first time, we have shown that a biodegradable anti-cancer drug eluting stent, BraidStent-SF-MMC, provides controlled and well-tolerated release of mitomycin into the upper urinary tract in an animal model. Mitomycin release from a silk fibroin coating could be a compelling approach for adjuvant chemotherapy instillation in upper tract urothelial carcinoma management.


Assuntos
Carcinoma de Células de Transição , Stents Farmacológicos , Fibroínas , Neoplasias da Bexiga Urinária , Feminino , Suínos , Animais , Mitomicina/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Carcinoma de Células de Transição/tratamento farmacológico , Carcinoma de Células de Transição/patologia , Fibroínas/uso terapêutico , Modelos Animais
4.
Polymers (Basel) ; 14(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36236029

RESUMO

Urothelial tumour of the upper urinary tract is a rare neoplasm, but unfortunately, it has a high recurrence rate. The reduction of these tumour recurrences could be achieved by the intracavitary instillation of adjuvant chemotherapy after nephron-sparing treatment in selected patients, but current instillation methods are ineffective. Therefore, the aim of this in vitro study is to evaluate the cytotoxic capacity of a new instillation technology through a biodegradable ureteral stent/scaffold coated with a silk fibroin matrix for the controlled release of mitomycin C as an anti-cancer drug. Through a comparative study, we assessed, in urothelial carcinoma cells in a human cancer T24 cell culture for 3 and 6 h, the cytotoxic capacity of mitomycin C by viability assay using the CCK-8 test (Cell counting Kit-8). Cell viability studies in the urothelial carcinoma cell line confirm that mitomycin C embedded in the polymeric matrix does not alter its cytotoxic properties and causes a significant decrease in cell viability at 6 h versus in the control groups. These findings have a clear biomedical application and could be of great use to decrease the recurrence rate in patients with upper tract urothelial carcinomas by increasing the dwell time of anti-cancer drugs.

5.
Polymers (Basel) ; 14(15)2022 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-35956574

RESUMO

A major limitation of the treatment of low-grade upper tract urothelial carcinoma is the difficulty of intracavitary instillation of adjuvant therapy. Therefore, the aim of this in vitro study was to develop and to assess a new design of biodegradable ureteral stent coated with a silk fibroin matrix for the controlled release of mitomycin C as a chemotherapeutic drug. For this purpose, we assessed the coating of a biodegradable ureteral stent, BraidStent®, with silk fibroin and subsequently loaded the polymeric matrix with two formulations of mitomycin to evaluate its degradation rate, the concentration of mitomycin released, and changes in the pH and the weight of the stent. Our results confirm that the silk fibroin matrix is able to coat the biodegradable stent and release mitomycin for between 6 and 12 h in the urinary environment. There was a significant delay in the degradation rate of silk fibroin and mitomycin-coated stents compared to bare biodegradable stents, from 6-7 weeks to 13-14 weeks. The present study has shown the feasibility of using mitomycin C-loaded silk fibroin for the coating of biodegradable urinary stents. The addition of mitomycin C to the coating of silk fibroin biodegradable stents could be an attractive approach for intracavitary instillation in the upper urinary tract.

6.
Soft Matter ; 18(26): 4973-4982, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35748816

RESUMO

Silk gut fibers were produced from the silkworm Samia cynthia ricini silk glands by the usual procedure of immersion in a mildly acidic solution and subsequent stretching. The morphology of the silk guts was assessed by scanning electron microscopy, and their microstructure was assessed by infrared spectroscopy and X-ray diffraction. It was found that both naturally spun and Samia silk guts share a common semicrystalline microstructure. The mechanical characterization of the silk guts revealed that these fibers show an elastomeric behavior when tested in water, and exhibit a genuine ground state to which the fiber may revert independently of its previous loading history. In spite of its large cross-sectional area compared with naturally spun silk fibers, Samia silk guts show values of work to fracture up to 160 MJ m-3, much larger than those of most of their natural counterparts, and establish a new record value for this parameter in silk guts.


Assuntos
Bombyx , Seda , Animais , Seda/química , Espectrofotometria Infravermelho , Difração de Raios X
7.
Int J Mol Sci ; 23(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35409245

RESUMO

High-performance fibroin fibres are ideal candidates for the manufacture of scaffolds with applications in tissue engineering due to the excellent mechanical properties and optimal biocompatibility of this protein. In this work, the manufacture of high-strength fibres made from the silk glands of Samia cynthia ricini is explored. The glands were subjected to soaking in aqueous dissolutions of acetic acid and stretched to manufacture the fibres. The materials produced were widely characterized, in terms of morphology, mechanical properties, crystallinity and content of secondary structures, comparing them with those produced by the standard procedure published for Bombyx mori. In addition, mechanical properties and biocompatibility of a braided scaffold produced from these fibres was evaluated. The results obtained show that the fibres from B. mori present a higher degree of crystallinity than those from S. c. ricini, which is reflected in higher values of elastic modulus and lower values of strain at break. Moreover, a decrease in the elongation values of the fibres from S. c. ricini was observed as the concentration of acetic acid was increased during the manufacture. On the other hand, the study of the braided scaffolds showed higher values of tensile strength and strain at break in the case of S. c. ricini materials and similar values of elastic modulus, compared to those of B. mori, displaying both scaffolds optimal biocompatibility using a fibroblast cell line.


Assuntos
Bombyx , Fibroínas , Manduca , Animais , Bombyx/metabolismo , Fibroínas/química , Manduca/metabolismo , Estrutura Secundária de Proteína , Seda/química , Engenharia Tecidual
8.
Insects ; 12(12)2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34940146

RESUMO

Sericulture generates different natural products with potential medical applications. Silk peptides, worms, or even pupae are commonly employed in traditional Asian medicine with a wide variety of purposes, and some scientific work has been focused on their antidiabetic properties. This work evaluates the postprandial antihyperglycemic activity of fibroin, sericin, and powder made from either larvae or pupae of silkworms, and Bombyx mori L. (Lepidoptera: Bombycidae), employing the silkworm itself as an animal model. The results indicate a reduction in the glucose levels in hemolymph after sucrose or glucose-induced hyperglycemia when these products are included in the diet of the worms.

9.
Lab Chip ; 21(3): 608-615, 2021 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-33404577

RESUMO

In optical biosensing, silk fibroin (SF) appears as a promising alternative where other materials, such as paper, find limitations. Besides its excellent optical properties and unmet capacity to stabilize biomacromolecules, SF in test strips exhibits additional functions, i.e. capillary pumping activity of 1.5 mm s-1, capacity to filter blood cells thanks to its small, but tuneable, porosity and enhanced biosensing sensitivity. The bulk functionalization of SF with the enzymes glucose oxidase and peroxidase and the mediator ABTS produces colourless and transparent SF films that respond to blood glucose increasing 2.5 times the sensitivity of conventional ABTS-based assays. This enhanced sensitivity results from the formation of SF-ABTS complexes, where SF becomes part of the bioassay. Additionally, SF films triple the durability of most stable cellulose-based sensors. Although demonstrated for glucose, SF microfluidic test strips may incorporate other optical bioassays, e.g. immunoassays, with the aim of transferring them from central laboratories to the place of patient's care.


Assuntos
Glicemia/análise , Fibroínas , Nanoporos , Ação Capilar , Humanos
10.
Sci Rep ; 10(1): 18471, 2020 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33116211

RESUMO

Spider mites constitute an assemblage of well-known pests in agriculture, but are less known for their ability to spin silk of nanoscale diameters and high Young's moduli. Here, we characterize silk of the gorse spider mite Tetranychus lintearius, which produces copious amounts of silk with nano-dimensions. We determined biophysical characteristics of the silk fibres and manufactured nanoparticles and biofilm derived from native silk. We determined silk structure using attenuated total reflectance Fourier transform infrared spectroscopy, and characterized silk nanoparticles using field emission scanning electron microscopy. Comparative studies using T. lintearius and silkworm silk nanoparticles and biofilm demonstrated that spider mite silk supports mammalian cell growth in vitro and that fluorescently labelled nanoparticles can enter cell cytoplasm. The potential for cytocompatibility demonstrated by this study, together with the prospect of recombinant silk production, opens a new avenue for biomedical application of this little-known silk.


Assuntos
Materiais Biocompatíveis , Teste de Materiais , Nanopartículas/química , Seda/química , Tetranychidae/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacocinética , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Módulo de Elasticidade , Camundongos , Microscopia Eletrônica de Varredura , Nanopartículas/ultraestrutura
11.
J Neural Eng ; 17(5): 055003, 2020 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-32947273

RESUMO

Age-related macular degeneration is an incurable chronic neurodegenerative disease, causing progressive loss of the central vision and even blindness. Up-to-date therapeutic approaches can only slow down he progression of the disease. OBJECTIVE: Feasibility study for a multilayered, silk fibroin-based, 3D biohybrid retina. APPROACH: Fabrication of silk fibroin-based biofilms; culture of different types of cells: retinal pigment epithelium, retinal neurons, Müller and mesenchymal stem cells ; creation of a layered structure glued with silk fibroin hydrogel. MAIN RESULTS: In vitro evidence for the feasibility of layered 3D biohybrid retinas; primary culture neurons grow and develop neurites on silk fibroin biofilms, either alone or in presence of other cells cultivated on the same biomaterial; cell organization and cellular phenotypes are maintained in vitro for the seven days of the experiment. SIGNIFICANCE: 3D biohybrid retina can be built using silk silkworm fibroin films and hydrogels to be used in cell replacement therapy for AMD and similar retinal neurodegenerative diseases.


Assuntos
Fibroínas , Degeneração Macular , Doenças Neurodegenerativas , Animais , Hidrogéis , Degeneração Macular/terapia , Retina
12.
Antioxidants (Basel) ; 9(1)2020 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-31963913

RESUMO

OBJECTIVE: the objective of the present work is to study the effectiveness of treatment with silk fibroin nanoparticles loaded with resveratrol in experimental periodontitis in a diabetic rat model. INTRODUCTION: Periodontitis is an inflammatory pathology highly related to other diseases, such as type II diabetes. Both diseases have a specific inflammatory condition, with Interleukin (IL)-6, IL-1ß and Transforming Grow Factor (TGF)-1ß being the most relevant proinflammatory factors. Silk fibroin (SF) nanoparticles loaded with resveratrol (Res-SFN) are a new alternative as a treatment. METHODS: 40 diabetic Sprague Dawley male rats were used and periodontitis was induced by ligation. The animals were divided into 5 treatment groups, and 1 mL of treatment was administered once a day for 4 weeks. The groups were: I: Carboxymethyl cellulose (CMC) 0.8%, II: CMC 0.8% + SF 1%, III: CMC 0.8% + RES-SFN 3 mg/mL, IV: CMC 0.8% + SF 1% + RES-SFN 3 mg/mL, V: Water. A peripheral blood sample was taken every week to quantify the inflammatory profile by ELISA (IL-6, IL-1ß and TGF-1ß). After 4 weeks the sacrifice was carried out and biopsies of the gum were taken. RESULTS: Treatment with SF and RES-SFN reduced the amount of chemical inflammation mediators (with the exception of IL-1ß in comparisons I-IV and II-IV (p > 0.05)), as well as the anatomopathological variables linked to it, in a significant way (p < 0.05). CONCLUSION: treatment with RES-SFN has reduced local inflammation in this experimental periodontitis model.

13.
RSC Adv ; 10(4): 1917-1924, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35494574

RESUMO

The photocatalytic properties of silk fibroin (SF) incorporating TiO2 nanoparticles using an electrospinning technique were examined. Electrospun SF/TiO2 mats were successfully prepared and characterized by different techniques (XRD, FE-SEM, XPS, XDS, FTIR and BET). The photocatalytic efficiency of these materials were assessed by their ability to degrade four pesticides (boscalid, hexythiazox, pyraclostrobin and trifloxystrobin) in water exposed to solar irradiation. The effect of catalyst loading on the disappearance kinetics of the different pesticides was studied in order to determine the maximum degradation efficiency. The degradation rate significantly increases upon adding the TiO2. However, no significant differences (p < 0.05) were observed when the TiO2 loading was increased from 25 to 50 mg for most compounds. Thus, SF mats with 25 mg of TiO2 were selected. Therefore, a new and simple approach to produce materials with photocatalytic activity, safety and potential application in the purification of water contaminated by pesticides has been developed.

14.
Polymers (Basel) ; 11(12)2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31835438

RESUMO

Several studies have stated that the process used for sericin removal, or degumming, from silk cocoons has a strong impact in the silk fibroin integrity and consequently in their mechanical or biochemical properties after processing it into several biomaterials (e.g. fibers, films or scaffolds) but still, there is a lack of information of the impact on the features of silk nanoparticles. In this work, silk cocoons were degummed following four standard methods: autoclaving, short alkaline (Na2CO3) boiling, long alkaline (Na2CO3) boiling and ultrasounds. The resultant silk fibroin fibers were dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate and used for nanoparticle synthesis by rapid desolvation in polar organic solvents. The relative efficiencies of the degumming processes and the integrity of the resulting fibroin fibers obtained were analyzed by mass loss, optical microscopy, thermogravimetric analysis, infrared spectroscopy and SDS-PAGE. Particle sizes and morphology were analyzed by Dynamic Light Scattering and Field Emission Scanning Electronic Microscopy. The results showed that the different treatments had a remarkable impact on the integrity of the silk fibroin chains, as confirmed by gel electrophoresis, which can be correlated with particle mean size and size distribution changes. The smallest nanoparticles (156 ± 3 nm) and the most negative Z potential (-30.2 ± 1.8 mV) were obtained with the combination of long treatment (2 h) of boiling in alkaline solution (Na2CO3 0.02 eq/L). The study confirms that parameters of the process, such as composition of the solution and time of the degumming step, must be controlled in order to reach an optimum reproducibility of the nanoparticle production.

15.
Sci Rep ; 9(1): 6703, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040313

RESUMO

Stifling treatments are applied to silk cocoons in order to kill the pupae, preventing the emergence of moths and allowing to preserve the silk during long periods of time. All of them involve the application of aggressive steps, such as sun exposure, hot steam from boiling water or hot air, during hours or even days. None of the scientific articles related to silk fibroin biomaterials has previously taken into account this fact in its section of materials and methods. In this work, the consequences of the stifling treatments most commonly used by the silk producing countries and companies are explored in depth, using fibroin films as biomaterial model. The protein degradation (visualised by SDS-PAGE) was dramatically increased in all the fibroin dissolutions produced from stifled cocoons; heavy and light chains of fibroin were specially degraded, reducing their presence along the lanes of the gel compared to the negative control (untreated fresh cocoons). Structural changes are also described for annealed silk fibroin films. The ß-sheet content, analysed by means of infrared spectroscopy, was significantly higher when stifling was performed at higher temperature (70 °C and 85 °C). It is also exposed the impact of the stifling on the mechanical properties of the materials. Tensile strength and strain at break values were detected as significantly lower when this procedure was carried out by means of dry heat (85 °C) and sun exposure. On the other hand, and contrary to expectations, the proliferation of fibroblasts growing on the materials was improved by all the different stifling methods, compared to negative control, being this improvement, especially accentuated, on the films produced with fibroin purified from cocoons treated with dry heat.


Assuntos
Materiais Biocompatíveis/química , Bombyx/química , Fibroínas/química , Seda/química , Animais , Técnicas de Cultura de Células/instrumentação , Proliferação de Células , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Fibroblastos/citologia , Humanos , Proteínas de Insetos/química , Pupa/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração
16.
Stem Cell Res Ther ; 10(1): 126, 2019 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029166

RESUMO

BACKGROUND: The treatment of extensive and/or chronic skin wounds is a widespread and costly public health problem. Mesenchymal stem cells (MSCs) have been proposed as a potential cell therapy for inducing wound healing in different clinical settings, alone or in combination with biosynthetic scaffolds. Among them, silk fibroin (SF) seeded with MSCs has been shown to have increased efficacy in skin wound healing experimental models. METHODS: In this report, we investigated the wound healing effects of electrospun SF scaffolds cellularized with human Wharton's jelly MSCs (Wj-MSCs-SF) using a murine excisional wound splinting model. RESULTS: Immunohistopathological examination after transplant confirmed the presence of infiltrated human fibroblast-like CD90-positive cells in the dermis of the Wj-MSCs-SF-treated group, yielding neoangiogenesis, decreased inflammatory infiltrate and myofibroblast proliferation, less collagen matrix production, and complete epidermal regeneration. CONCLUSIONS: These findings indicate that Wj-MSCs transplanted in the wound bed on a silk fibroin scaffold contribute to the generation of a well-organized and vascularized granulation tissue, enhance reepithelization of the wound, and reduce the formation of fibrotic scar tissue, highlighting the potential therapeutic effects of Wj-MSC-based tissue engineering approaches to non-healing wound treatment.


Assuntos
Cicatriz/terapia , Fibroínas/farmacologia , Alicerces Teciduais , Geleia de Wharton/metabolismo , Animais , Cicatriz/patologia , Fibroblastos/metabolismo , Humanos , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos , Reepitelização/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/lesões , Pele/patologia , Engenharia Tecidual , Cicatrização/efeitos dos fármacos
17.
Soft Matter ; 15(14): 2960-2970, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30901019

RESUMO

Tubuliform silk glands were dissected from Nephila clavipes spiders, and silk gut fibers were produced by immersing the glands in a mild acid solution and subsequent stretching. The tensile properties of the as produced fibers were obtained through tensile tests, and the stress-strain curves were compared with those of naturally spun tubuliform silk fibers. The influence on the mechanical properties of the fibers after immersion in water and drying was also discerned. The microstructure of the silk guts was obtained by X-ray diffraction (XRD) and infrared spectroscopy (FTIR). It was found that the stress-strain curves of the stretched tubuliform silk guts concur with those of their natural counterparts (tubuliform silk fibers).


Assuntos
Seda/química , Aranhas/química , Animais , Resistência à Tração
18.
J Biomed Mater Res B Appl Biomater ; 107(7): 2209-2215, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30675993

RESUMO

Tendon and ligament tissue engineering require scaffolds for the treatment of various conditions in the medical field. These must meet requirements such as high tensile strength, biocompatibility, fast and stable repair and a rate of degradation that allows the repair of the damaged tissue. In this work, we propose the use of silkworm gut fiber braids as materials to temporarily replace and repair this type of tissues. The mechanical characterization of the braids made with different number of silk gut fibers is provided, as well as a descriptive analysis of the proliferation and adhesion of cultures of adult human mesenchymal stem cells from bone marrow and fibroblasts (L929) on the braids. As expected, the breaking force increases linearly in the scaffold with the number of fibers, thus being a parameter adaptable to the specific requirements of the tissue to repair and the animal model of study. On the other hand, in all of the cases studied, the values obtained for the elastic modulus of the hydrated fibers were in the range of the ones reported for various human tendons and ligaments. Moreover, the scaffold demonstrated excellent biocompatibility in vitro, allowing the adhesion and proliferation, in the same culture conditions, of the two cell types studied, therefore posing as an ideal candidate to be employed in future in vivo studies that allow elucidating its behavior in the articular environment or extra-articular tendinous areas. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: 2019. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2209-2215, 2019.


Assuntos
Bombyx , Intestinos/química , Ligamentos , Células-Tronco Mesenquimais , Tendões , Engenharia Tecidual , Alicerces Teciduais/química , Animais , Linhagem Celular , Ligamentos/citologia , Ligamentos/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Tendões/citologia , Tendões/metabolismo
19.
Materials (Basel) ; 10(4)2017 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-28772708

RESUMO

The purpose of this study was to evaluate the bioactivity and cell response of a well-characterized Nurse's A-phase (7CaO·P2O5·2SiO2) ceramic and its effect compared to a control (tissue culture polystyrene-TCPS) on the adhesion, viability, proliferation, and osteogenic differentiation of ahMSCs in vitro. Cell proliferation (Alamar Blue Assay), Alizarin Red-S (AR-s) staining, alkaline phosphatase (ALP) activity, osteocalcin (OCN), and collagen I (Col I) were evaluated. Also, field emission scanning electron microscopy (FESEM) images were acquired in order to visualise the cells and the topography of the material. The proliferation of cells growing in a direct contact with the material was slower at early stages of the study because of the new environmental conditions. However, the entire surface was colonized after 28 days of culture in growth medium (GM). Osteoblastic differentiation markers were significantly enhanced in cells growing on Nurse's A phase ceramic and cultured with osteogenic medium (OM), probably due to the role of silica to stimulate the differentiation of ahMSCs. Moreover, calcium nodules were formed under the influence of ceramic material. Therefore, it is predicted that Nurse's A-phase ceramic would present high biocompatibility and osteoinductive properties and would be a good candidate to be used as a biomaterial for bone tissue engineering.

20.
Invest Ophthalmol Vis Sci ; 58(9): 3357-3365, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28687847

RESUMO

Purpose: Develop a silk fibroin (SF)-based artificial endothelial graft for its use in a rabbit Descemet membrane endothelial keratoplasty (DMEK). Methods: Human and rabbit artificial corneal endothelial grafts were developed through the culture of human and rabbit corneal endothelial cells (CECs) on SF films. Rabbit artificial SF endothelial grafts were transplanted in a DMEK surgery into a rabbit in vivo model. Results: SF artificial endothelial grafts showed the characteristic endothelial markers: zonula occludens (ZO-1) and Na+/K+ ATPase. In a rabbit model of DMEK surgery, SF artificial endothelial graft restored the corneal transparency and thickness at 6 week of follow-up. Anterior segment optical coherence tomography revealed the SF graft as a fully integrated component in the corneal tissue, displaying a similar corneal thickness and endothelial cell count when compared with its healthy contralateral cornea. Histologic analysis showed that the SF artificial endothelial graft was attached and integrated on the surface of the corneal stroma without a significant inflammatory reaction, and rabbit CECs consisted in a monolayer that showed their characteristic markers ZO-1 and Na+/K+ ATPase, suggesting proper intercellular junctions and cellular pump function. Conclusions: We have developed SF films with biological properties that supported the growth of rabbit and human CECs, which showed normal morphology and characteristic markers; and with mechanical properties that allowed its use in a DMEK surgery, proving its in vivo functionality in a rabbit model of endothelial dysfunction.


Assuntos
Edema da Córnea/cirurgia , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/métodos , Endotélio Corneano/transplante , Fibroínas , Membranas Artificiais , Seda , Engenharia Tecidual , Animais , Células Cultivadas , Edema da Córnea/patologia , Modelos Animais de Doenças , Células Endoteliais/citologia , Humanos , Coelhos , Engenharia Tecidual/métodos
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