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1.
ACS Appl Bio Mater ; 7(2): 853-862, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38270977

RESUMEN

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.


Asunto(s)
Técnicas Biosensibles , Seda , Seda/química , Colorimetría/métodos , Peroxidasas , Técnicas Biosensibles/métodos , Peroxidasa , Glucosa
2.
Dent Mater ; 40(3): 431-440, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38114344

RESUMEN

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.


Asunto(s)
Fibroínas , Grafito , Humanos , Fibroínas/química , Andamios del Tejido/química , Ingeniería de Tejidos/métodos , Grafito/química , Pulpa Dental , Diferenciación Celular , Agua , Proliferación Celular , Células Madre
3.
Minerva Urol Nephrol ; 75(2): 194-202, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36999837

RESUMEN

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.


Asunto(s)
Carcinoma de Células Transicionales , Stents Liberadores de Fármacos , Fibroínas , Neoplasias de la Vejiga Urinaria , Femenino , Porcinos , Animales , Mitomicina/uso terapéutico , Neoplasias de la Vejiga Urinaria/tratamiento farmacológico , Carcinoma de Células Transicionales/tratamiento farmacológico , Carcinoma de Células Transicionales/patología , Fibroínas/uso terapéutico , Modelos Animales
4.
Polymers (Basel) ; 14(19)2022 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-36236029

RESUMEN

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.
Soft Matter ; 18(26): 4973-4982, 2022 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-35748816

RESUMEN

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.


Asunto(s)
Bombyx , Seda , Animales , Seda/química , Espectrofotometría Infrarroja , Difracción de Rayos X
6.
Int J Mol Sci ; 23(7)2022 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-35409245

RESUMEN

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.


Asunto(s)
Bombyx , Fibroínas , Manduca , Animales , Bombyx/metabolismo , Fibroínas/química , Manduca/metabolismo , Estructura Secundaria de Proteína , Seda/química , Ingeniería de Tejidos
7.
Insects ; 12(12)2021 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-34940146

RESUMEN

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.

8.
Lab Chip ; 21(3): 608-615, 2021 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-33404577

RESUMEN

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.


Asunto(s)
Glucemia/análisis , Fibroínas , Nanoporos , Acción Capilar , Humanos
9.
J Neural Eng ; 17(5): 055003, 2020 10 31.
Artículo en Inglés | MEDLINE | ID: mdl-32947273

RESUMEN

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.


Asunto(s)
Fibroínas , Degeneración Macular , Enfermedades Neurodegenerativas , Animales , Hidrogeles , Degeneración Macular/terapia , Retina
10.
Antioxidants (Basel) ; 9(1)2020 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-31963913

RESUMEN

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.

11.
Polymers (Basel) ; 11(12)2019 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-31835438

RESUMEN

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.

12.
Sci Rep ; 9(1): 6703, 2019 04 30.
Artículo en Inglés | MEDLINE | ID: mdl-31040313

RESUMEN

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.


Asunto(s)
Materiales Biocompatibles/química , Bombyx/química , Fibroínas/química , Seda/química , Animales , Técnicas de Cultivo de Célula/instrumentación , Proliferación Celular , Células Cultivadas , Electroforesis en Gel de Poliacrilamida , Fibroblastos/citología , Humanos , Proteínas de Insectos/química , Pupa/química , Espectroscopía Infrarroja por Transformada de Fourier , Resistencia a la Tracción
13.
Stem Cell Res Ther ; 10(1): 126, 2019 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-31029166

RESUMEN

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.


Asunto(s)
Cicatriz/terapia , Fibroínas/farmacología , Andamios del Tejido , Gelatina de Wharton/metabolismo , Animales , Cicatriz/patología , Fibroblastos/metabolismo , Humanos , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/efectos de los fármacos , Ratones , Repitelización/efectos de los fármacos , Piel/efectos de los fármacos , Piel/lesiones , Piel/patología , Ingeniería de Tejidos , Cicatrización de Heridas/efectos de los fármacos
14.
Soft Matter ; 15(14): 2960-2970, 2019 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-30901019

RESUMEN

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).


Asunto(s)
Seda/química , Arañas/química , Animales , Resistencia a la Tracción
15.
J Biomed Mater Res B Appl Biomater ; 107(7): 2209-2215, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-30675993

RESUMEN

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.


Asunto(s)
Bombyx , Intestinos/química , Ligamentos , Células Madre Mesenquimatosas , Tendones , Ingeniería de Tejidos , Andamios del Tejido/química , Animales , Línea Celular , Ligamentos/citología , Ligamentos/metabolismo , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , Ratones , Tendones/citología , Tendones/metabolismo
16.
Invest Ophthalmol Vis Sci ; 58(9): 3357-3365, 2017 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-28687847

RESUMEN

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.


Asunto(s)
Edema Corneal/cirugía , Queratoplastia Endotelial de la Lámina Limitante Posterior/métodos , Endotelio Corneal/trasplante , Fibroínas , Membranas Artificiales , Seda , Ingeniería de Tejidos , Animales , Células Cultivadas , Edema Corneal/patología , Modelos Animales de Enfermedad , Células Endoteliales/citología , Humanos , Conejos , Ingeniería de Tejidos/métodos
17.
ACS Appl Mater Interfaces ; 8(41): 27974-27986, 2016 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-27704765

RESUMEN

Chemically exfoliated MoS2 (ce-MoS2) has emerged in recent years as an attractive two-dimensional material for use in relevant technological applications, but fully exploiting its potential and versatility will most probably require the deployment of appropriate chemical modification strategies. Here, we demonstrate that extensive covalent functionalization of ce-MoS2 nanosheets with acetic acid groups (∼0.4 groups grafted per MoS2 unit) based on the organoiodide chemistry brings a number of benefits in terms of their processability and functionality. Specifically, the acetic acid-functionalized nanosheets were furnished with long-term (>6 months) colloidal stability in aqueous medium at relatively high concentrations, exhibited a markedly improved temporal retention of catalytic activity toward the reduction of nitroarenes, and could be more effectively coupled with silver nanoparticles to form hybrid nanostructures. Furthermore, in vitro cell proliferation tests carried out with murine fibroblasts suggested that the chemical derivatization had a positive effect on the biocompatibility of ce-MoS2. A hydrothermal annealing procedure was also implemented to promote the structural conversion of the functionalized nanosheets from the 1T phase that was induced during the chemical exfoliation step to the original 2H phase of the starting bulk material, while retaining at the same time the aqueous colloidal stability afforded by the presence of the acetic acid groups. Overall, by highlighting the benefits of this type of chemical derivatization, the present work should contribute to strengthen the position of ce-MoS2 as a two-dimensional material of significant practical utility.

18.
Int J Mol Sci ; 17(7)2016 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-27438824

RESUMEN

This work describes a new approach to the delivery of light in deeper tissues, through a silk filament that is implantable, biocompatible, and biodegradable. In the present work, silkworm gut fibers (SGFs) of Bombyx mori L., are made by stretching the silk glands. Morphological, structural, and optical properties of the fibers have been characterized and the stimulatory effect of red laser light diffused from the fiber was assayed in fibroblast cultures. SGFs are formed by silk fibroin (SF) mainly in a ß-sheet conformation, a stable and non-soluble state in water or biological fluids. The fibers showed a high degree of transparency to visible and infrared radiation. Using a red laser (λ = 650 nm) as source, the light was efficiently diffused along the fiber wall, promoting a significant increment in the cell metabolism 5 h after the irradiation. SGFs have shown their excellent properties as light-diffusing optical fibers with a stimulatory effect on cells.


Asunto(s)
Materiales Biocompatibles/química , Bombyx/metabolismo , Tracto Gastrointestinal/metabolismo , Luz , Prótesis e Implantes , Seda/química , Resistencia a la Tracción/efectos de la radiación , Animales , Materiales Biocompatibles/metabolismo , Proliferación Celular/efectos de la radiación , Células Cultivadas , Fibroblastos/citología , Fibroblastos/metabolismo , Fibroblastos/efectos de la radiación , Ratones , Seda/metabolismo
19.
Soft Matter ; 11(46): 8981-91, 2015 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-26403149

RESUMEN

High performance silk fibers were produced directly from the silk glands of silkworms (Bombyx mori) following an alternative route to natural spinning. This route is based on a traditional procedure that consists of soaking the silk glands in a vinegar solution and stretching them by hand leading to the so called silkworm guts. Here we present, to the authors' best knowledge, the first comprehensive study on the formation, properties and microstructure of silkworm gut fibers. Comparison of the tensile properties and microstructural organization of the silkworm guts with those of naturally spun fibers allows gain of a deeper insight into the mechanisms that lead to the formation of the fiber, as well as the relationship between the microstructure and properties of these materials. In this regard, it is proved that an acidic environment and subsequent application of tensile stress in the range of 1000 kPa are sufficient conditions for the formation of a silk fiber.


Asunto(s)
Bombyx , Seda/química , Resistencia a la Tracción , Animales , Seda/biosíntesis , Seda/metabolismo , Espectrofotometría Infrarroja , Difracción de Rayos X
20.
Angew Chem Int Ed Engl ; 54(23): 6790-4, 2015 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-25951010

RESUMEN

The current technology of air-filtration materials for protection against highly toxic chemicals, that is, chemical-warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self-cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal-organic framework (MOF) materials to develop advanced self-detoxifying adsorbents of chemical-warfare agents containing hydrolysable P-F, P-O, and C-Cl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air-permeation properties of the textiles with the self-detoxifying properties of the MOF material.


Asunto(s)
Sustancias para la Guerra Química/química , Sustancias para la Guerra Química/aislamiento & purificación , Filtración/métodos , Compuestos Organometálicos/química , Hidrolasas de Triéster Fosfórico/metabolismo , Textiles , Circonio/química , Adsorción , Biocatálisis , Sustancias para la Guerra Química/toxicidad , Estructura Molecular , Compuestos Organometálicos/metabolismo , Circonio/metabolismo
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