RESUMEN
Hydrogel patches with high toughness, stretchability, and adhesive properties are critical to healthcare applications including wound dressings and wearable devices. Gelatin methacryloyl (GelMA) provides a highly biocompatible and accessible hydrogel platform. However, low tissue adhesion and poor mechanical properties of cross-linked GelMA patches (i.e., brittleness and low stretchability) have been major obstacles to their application for sealing and repair of wounds. Here, we show that adding dopamine (DA) moieties in larger quantities than those of conjugated counterparts to the GelMA prepolymer solution followed by alkaline DA oxidation could result in robust mechanical and adhesive properties in GelMA-based hydrogels. In this way, cross-linked patches with â¼140% stretchability and â¼19â¯000 J/m3 toughness, which correspond to â¼5.7 and â¼3.3× improvement, respectively, compared to that of GelMA controls, were obtained. The DA oxidization in the prepolymer solution was found to play an important role in activating adhesive properties of cross-linked GelMA patches (â¼4.0 and â¼6.9× increase in adhesion force under tensile and shear modes, respectively) due to the presence of reactive oxidized quinone species. We further conducted a parametric study on the factors such as UV light parameters, the photoinitiator type (i.e., lithium phenyl-2,4,6-trimethylbenzoylphosphinate, LAP, versus 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, Irgacure 2959), and alkaline DA oxidation to tune the cross-linking density and thereby hydrogel compliance for better adhesive properties. The superior adhesion performance of the resulting hydrogel along with in vitro cytocompatibility demonstrated its potential for use in skin-attachable substrates.
Asunto(s)
Adhesivos/química , Gelatina/química , Hidrogeles/química , Indoles/química , Metacrilatos/química , Polímeros/química , Adhesivos/síntesis química , Adhesivos/toxicidad , Animales , Supervivencia Celular/efectos de los fármacos , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Reactivos de Enlaces Cruzados/toxicidad , Dopamina/química , Dopamina/efectos de la radiación , Gelatina/efectos de la radiación , Gelatina/toxicidad , Hidrogeles/síntesis química , Hidrogeles/toxicidad , Indoles/síntesis química , Indoles/toxicidad , Ensayo de Materiales , Metacrilatos/efectos de la radiación , Metacrilatos/toxicidad , Ratones , Células 3T3 NIH , Polimerizacion/efectos de la radiación , Polímeros/síntesis química , Polímeros/toxicidad , Piel/metabolismo , Porcinos , Resistencia a la Tracción , Rayos UltravioletaRESUMEN
Tissue adhesives have been developed for sealing tissue damaged in surgery. Among these, sheet-type adhesives require a relatively long time to adhere to biological tissue under wet conditions. To address this clinical problem, we fabricated a tissue-adhesive fiber sheet (AdFS) based on decanyl group (C10) modified Alaska pollock-derived gelatin (C10-ApGltn) using electrospinning. Ultraviolet (UV) irradiation of the AdFS was performed to increase the affinity between the AdFS and wet biological tissue by introducing hydrophilic functional groups. The UV irradiated AdFS (UV-C10-AdFS) strongly adhered to porcine pleura within 2 min under wet conditions and showed higher burst strength compared with the original ApGltn (Org-ApGltn) sheet. Hematoxylin-eosin stained sections revealed that a dense UV-C10-AdFS layer remained on the surface of the porcine pleura even after burst strength measurement. Moreover, UV-C10-AdFS has excellent cytocompatibility and efficiently supports the growth of L929 cells. UV-C10-AdFS is a promising adhesive material for sealing wet biological tissue.
Asunto(s)
Gelatina/química , Pleura/efectos de los fármacos , Adhesivos Tisulares/química , Adhesivos Tisulares/efectos de la radiación , Alaska , Animales , Línea Celular , Técnicas Electroquímicas , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Gadiformes/metabolismo , Gelatina/efectos de la radiación , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Ratones , Pleura/efectos de la radiación , Polietilenglicoles/química , Porcinos , Resistencia a la Tracción , Adhesivos Tisulares/farmacología , Rayos UltravioletaRESUMEN
Bioinks play a key role in determining the capability of the biofabricatoin processes and the resolution of the printed constructs. Excellent biocompatibility, tunable physical properties, and ease of chemical or biological modifications of gelatin methacryloyl (GelMA) have made it an attractive choice as bioinks for biomanufacturing of various tissues or organs. However, the current preparation methods for GelMA-based bioinks lack the ability to tailor their physical properties for desired bioprinting methods. Inherently, GelMA prepolymer solution exhibits a fast sol-gel transition at room temperature, which is a hurdle for its use in stereolithography (SLA) bioprinting. Here, synthesis parameters are optimized such as solvents, pH, and reaction time to develop GelMA bioinks which have a slow sol-gel transition at room temperature and visible light crosslinkable functions. A total of eight GelMA combinations are identified as suitable for digital light processing (DLP)-based SLA (DLP-SLA) bioprinting through systematic characterizations of their physical and rheological properties. Out of various types of GelMA, those synthesized in reverse osmosis (RO) purified water (referred to as RO-GelMA) are regarded as most suitable to achieve high DLP-SLA printing resolution. RO-GelMA-based bioinks are also found to be biocompatible showing high survival rates of encapsulated cells in the photocrosslinked gels. Additionally, the astrocytes and fibroblasts are observed to grow and integrate well within the bioprinted constructs. The bioink's superior physical and photocrosslinking properties offer pathways of tuning the scaffold microenvironment and highlight the applicability of developed GelMA bioinks in various tissue engineering and regenerative medicine applications.
Asunto(s)
Bioimpresión , Gelatina/farmacología , Metacrilatos/farmacología , Estereolitografía , Ingeniería de Tejidos , Supervivencia Celular/efectos de los fármacos , Gelatina/síntesis química , Gelatina/efectos de la radiación , Humanos , Hidrogeles/química , Hidrogeles/farmacología , Tinta , Luz , Metacrilatos/síntesis química , Metacrilatos/efectos de la radiación , Impresión Tridimensional , Andamios del Tejido/químicaRESUMEN
Adipose tissue engineering aims to provide solutions to patients who require tissue reconstruction following mastectomies or other soft tissue trauma. Mesenchymal stromal cells (MSCs) robustly differentiate into the adipogenic lineage and are attractive candidates for adipose tissue engineering. This work investigates whether pore size modulates adipogenic differentiation of MSCs toward identifying optimal scaffold pore size and whether pore size modulates spatial infiltration of adipogenically differentiated cells. To assess this, extrusion-based 3D printing is used to fabricate photo-crosslinkable gelatin-based scaffolds with pore sizes in the range of 200-600 µm. The adipogenic differentiation of MSCs seeded onto these scaffolds is evaluated and robust lipid droplet formation is observed across all scaffold groups as early as after day 6 of culture. Expression of adipogenic genes on scaffolds increases significantly over time, compared to TCP controls. Furthermore, it is found that the spatial distribution of cells is dependent on the scaffold pore size, with larger pores leading to a more uniform spatial distribution of adipogenically differentiated cells. Overall, these data provide first insights into the role of scaffold pore size on MSC-based adipogenic differentiation and contribute toward the rational design of biomaterials for adipose tissue engineering in 3D volumetric spaces.
Asunto(s)
Adipocitos/efectos de los fármacos , Materiales Biocompatibles/farmacología , Gelatina/química , Células Madre Mesenquimatosas/efectos de los fármacos , Ingeniería de Tejidos/métodos , Andamios del Tejido , Adipocitos/citología , Adipocitos/metabolismo , Adipogénesis/efectos de los fármacos , Adipogénesis/genética , Tejido Adiposo/citología , Tejido Adiposo/metabolismo , Materiales Biocompatibles/química , Materiales Biocompatibles/efectos de la radiación , Biomarcadores/metabolismo , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Acido Graso Sintasa Tipo I/genética , Acido Graso Sintasa Tipo I/metabolismo , Proteínas de Unión a Ácidos Grasos/genética , Proteínas de Unión a Ácidos Grasos/metabolismo , Gelatina/efectos de la radiación , Expresión Génica , Humanos , Lipoproteína Lipasa/genética , Lipoproteína Lipasa/metabolismo , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/metabolismo , PPAR gamma/genética , PPAR gamma/metabolismo , Porosidad , Cultivo Primario de Células , Impresión Tridimensional , Rayos UltravioletaRESUMEN
In this study, the composite of carboxymethyl cellulose (CMC) film modified with gelatin and TiO2-Ag nanoparticles (CMC/Gel/TiO2-Ag) was prepared and some properties of synthesized film including physicochemical and photocatalytic properties were investigated. FT-IR results showed that new interactions between the film components were created. Scanning electron microscopy (SEM) results showed that the TiO2-Ag particles with 50-100 nm distributed in the CMC/Gelatin film. The results of the mechanical test showed that the TiO2-Ag nanoparticles at low concentrations increased tensile strength (TS) and decreased strain to break (STB), but with increasing nanoparticles concentrations, TS decreased and STB increased. Photocatalytic study showed that the prepared CMC/Gel/TiO2-Ag film has good photocatalytic property. Gas chromatography was used to study photocatalytic effects of film. Increasing TiO2-Ag nano particles on the film increases the photocatalytic activity of films against NH3, ethanol and benzene.
Asunto(s)
Plásticos Biodegradables/química , Carboximetilcelulosa de Sodio/química , Gelatina/química , Nanopartículas del Metal/química , Plata/química , Titanio/química , Amoníaco/química , Benceno/química , Plásticos Biodegradables/síntesis química , Plásticos Biodegradables/efectos de la radiación , Carboximetilcelulosa de Sodio/síntesis química , Carboximetilcelulosa de Sodio/efectos de la radiación , Catálisis , Módulo de Elasticidad , Etanol/química , Gelatina/síntesis química , Gelatina/efectos de la radiación , Luz , Membranas Artificiales , Nanopartículas del Metal/efectos de la radiación , Nanocompuestos/química , Nanocompuestos/efectos de la radiación , Permeabilidad , Plata/efectos de la radiación , Vapor , Resistencia a la Tracción , Titanio/efectos de la radiación , Agua/químicaRESUMEN
The effects of ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) methods on molecular and physicochemical characteristics of the resultant gelatin were examined. Before extraction procedure, we investigated the optimum pH for swelling of Common carp by-products, which is an important pretreatment for gelatin production. The highest swelling yield was achieved at pH 13 among pH 1-14 with unit intervals. Results indicated that the UAE gelatin has a higher gel strength, viscosity, melting point, and gelling point. The power and time of sonication showed a reverse relation with these characteristics. In addition, as the time of microwave heating was raised, the gel strength, viscosity, melting point, and gelling point were decreased. The FT-IR spectra showed similar peaks but the Amide B in UAE gelatin slightly vanished. The electrophoretic pattern also revealed the higher gel strength and viscosity of UAE gelatin due to the higher intensity of α and ß chains compared to MAE gelatin. It can be concluded from all of the results of this study that the produced gelatin using these procedures can be a good source of gelatin in food and drug industries.
Asunto(s)
Carpas , Gelatina/química , Gelatina/efectos de la radiación , Microondas , Reología , Ondas Ultrasónicas , Aletas de Animales/química , Animales , Fraccionamiento Químico , Fenómenos Químicos , Coloides/química , Coloides/efectos de la radiación , Color , Tecnología de Alimentos , Geles/química , Concentración de Iones de Hidrógeno , Irán , Piel/química , Temperatura , Temperatura de Transición , ViscosidadRESUMEN
Hard capsules are made from gelatin, an organic polymer obtained through the hydrolysis of collagen present in animal tissues. Gelatin can be degraded by microorganisms and some strategies can be used to control contaminating micro-organisms. Gamma irradiation is considered as an effective sterilization method; however, its application can alter the chemical structure of the irradiated product. Samples of hard gelatin capsules were irradiated at doses of 5, 15, and 25 kGy at room temperature. The characterizations of the physical and chemical effects were evaluated by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, and differential scanning calorimetry techniques. Furthermore, hard gelatin capsule samples were dissolved and inoculated with Bacillus subtilis, a Gram-positive spore-forming bacterium, to evaluate the effect of gamma ray radiation on bacterial counts. The results showed that gamma radiation did not interfere on physical parameters of the capsule, such as moisture content, mass, body and cap length, and disintegration time. Nevertheless, differential scanning calorimetry results demonstrated changes in the glass transition temperature, indicating the formation of crosslinking in irradiated capsules. It was observed that there were significant reductions on the inoculated bacterial population starting from the lowest irradiation dose and there was no detection of bacterial growth from the 15 kGy dose, while in the non-irradiated samples were found with 104 CFU mL-1 of bacteria. Therefore, this work concludes that the gamma radiation is effective on the reduction of the microbial population, cause discrete physical-chemical alterations, and could be used as a hard capsule sterilization technique.
Asunto(s)
Cápsulas/efectos de la radiación , Rayos gamma , Gelatina/efectos de la radiación , Esterilización/métodos , Rastreo Diferencial de Calorimetría , Cápsulas/química , Gelatina/químicaRESUMEN
In this study, the cyto-compatibility and cellular functionality of cell-laden gelatin-methacryloyl (Gel-MA) hydrogels fabricated using a set of photo-initiators which absorb in 400-450 nm of the visible light range are investigated. Gel-MA hydrogels cross-linked using ruthenium (Ru) and sodium persulfate (SPS), are characterized to have comparable physico-mechanical properties as Gel-MA gels photo-polymerized using more conventionally adopted photo-initiators, such as 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Irgacure 2959) and lithium phenyl(2,4,6-trimethylbenzoyl) phosphinate (LAP). It is demonstrated that the Ru/SPS system has a less adverse effect on the viability and metabolic activity of human articular chondrocytes encapsulated in Gel-MA hydrogels for up to 35 days. Furthermore, cell-laden constructs cross-linked using the Ru/SPS system have significantly higher glycosaminoglycan content and re-differentiation capacity as compared to cells encapsulated using I2959 and LAP. Moreover, the Ru/SPS system offers significantly greater light penetration depth as compared to the I2959 system, allowing thick (10 mm) Gel-MA hydrogels to be fabricated with homogenous cross-linking density throughout the construct. These results demonstrate the considerable advantages of the Ru/SPS system over traditional UV polymerizing systems in terms of clinical relevance and practicability for applications such as cell encapsulation, biofabrication, and in situ cross-linking of injectable hydrogels.
Asunto(s)
Diferenciación Celular/efectos de los fármacos , Microambiente Celular/efectos de los fármacos , Hidrogeles/farmacología , Ingeniería de Tejidos , Diferenciación Celular/efectos de la radiación , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Condrocitos/efectos de los fármacos , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Gelatina/química , Gelatina/farmacología , Gelatina/efectos de la radiación , Humanos , Hidrogeles/química , Hidrogeles/efectos de la radiación , Luz , Polimerizacion/efectos de los fármacos , Polimerizacion/efectos de la radiación , Polímeros/química , Polímeros/farmacologíaRESUMEN
This study investigated a novel method of photosensitizer-induced cross-linking (using riboflavin as a sensitizer) to improve the structural and physicochemical properties of gelatin-based edible films with different glycerol concentrations (25% and 50%) during different UV exposure times (2, 4 and 6â¯h). The films' tensile strength was enhanced significantly for both glycerol concentrations with increasing UV exposure times compared to the control film, so that the highest tensile strength was observed for films with 25% glycerol and 6â¯h of UV exposure (25%-6â¯h). The films' tensile strength declined and the elongation at break increased about three times when the glycerol concentration was increased to 50% with 6â¯h exposure. The photosensitizer-induced cross-linking significantly reduced the films' solubility and permeability. The UV-treated films exhibited very good barrier properties against UV, with zero light transmission at a wavelength of 200 to 350â¯nm. Moreover, no toxicity was found in any of the films. In addition, Fourier transform infrared spectroscopy and differential scanning calorimetry findings revealed a good interaction between functional groups of riboflavin (as the sensitizer) and gelatin in the 25%-6â¯h film. Therefore, this new method can be a suitable alternative to chemical methods of cross-linking biopolymers.
Asunto(s)
Embalaje de Alimentos/métodos , Gelatina/efectos de la radiación , Oxidantes Fotoquímicos/química , Riboflavina/química , Rayos Ultravioleta , Animales , Rastreo Diferencial de Calorimetría , Supervivencia Celular/efectos de los fármacos , Gelatina/química , Gelatina/toxicidad , Glicerol/química , Humanos , Ratones , Células 3T3 NIH , Oxidantes Fotoquímicos/toxicidad , Oxidación-Reducción , Permeabilidad , Solubilidad , Espectroscopía Infrarroja por Transformada de Fourier , Resistencia a la Tracción , Factores de TiempoRESUMEN
Recent developments in radiation therapy aimed at more precise dose delivery along with higher dose gradients (dose painting) and more efficient dose delivery with higher dose rates e.g. flattening filter free (FFF) irradiation. Magnetic-resonance-imaging based polymer gel dosimetry offers 3D information for precise dose delivery techniques. Many of the proposed polymer gels have been reported to exhibit a dose response, measured as relaxation rate ΔR2(D), which is dose rate dependent. A lack of or a reduced dose-rate sensitivity is very important for dosimetric accuracy, especially with regard to the increasing clinical use of FFF irradiation protocols with LINACs at high dose rates. Some commonly used polymer gels are based on Methacrylic-Acid-Gel-Initiated-by-Copper (MAGIC). Here, we report on the dose sensitivity (ΔR2/ΔD) of MAGIC-type gels with different oxygen scavenger concentration for their specific dependence on the applied dose rate in order to improve the dosimetric performance, especially for high dose rates. A preclinical x-ray machine ('Yxlon', E = 200 kV) was used for irradiation to cover a range of dose rates from low [Formula: see text] min = 0.6 Gy min-1 to high [Formula: see text] max = 18 Gy min-1. The dose response was evaluated using R2-imaging of the gel on a human high-field (7T) MR-scanner. The results indicate that all of the investigated dose rates had an impact on the dose response in polymer gel dosimeters, being strongest in the high dose region and less effective for low dose levels. The absolute dose rate dependence [Formula: see text] of the dose response in MAGIC-type gel is significantly reduced using higher concentrations of oxygen scavenger at the expense of reduced dose sensitivity. For quantitative dose evaluations the relative dose rate dependence of a polymer gel, normalized to its sensitivity is important. Based on this normalized sensitivity the dose rate sensitivity was reduced distinctly using an increased oxygen scavenger concentration with reference to standard MAGIC-type gel formulation at high dose rate levels. The proposed gel composition with high oxygen scavenger concentration exhibits a larger linear active dose response and might be used especially in FFF-radiation applications and preclinical dosimetry at high dose rates. We propose in general to use high dose rates for calibration and evaluation as the change in relative dose sensitivity is reduced at higher dose rates in all of the investigated gel types.
Asunto(s)
Ácido Ascórbico/química , Sulfato de Cobre/química , Depuradores de Radicales Libres/química , Gelatina/química , Hidroquinonas/química , Imagen por Resonancia Magnética/métodos , Metacrilatos/química , Oxígeno/química , Polímeros/química , Radiometría/métodos , Ácido Ascórbico/efectos de la radiación , Calibración , Sulfato de Cobre/efectos de la radiación , Gelatina/efectos de la radiación , Humanos , Hidroquinonas/efectos de la radiación , Metacrilatos/efectos de la radiación , Polímeros/efectos de la radiación , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por ComputadorRESUMEN
BACKGROUND: In this paper, two kinds of commonly used vegetable carbon black (VCB, 3000 mesh; nano) at 50 g kg-1 concentration (based on dried gelatin) were added to 48 g kg-1 of fish gelatin (GEL) solutions and their effects on mechanical, barrier and anti-photooxidation properties of GEL films were investigated. RESULTS: From the SEM images, it was shown that compared with 3000 mesh VCB (1-2 µm), nano VCB (100-200 nm) made the microstructure of GEL film more compact and more gelatin chains were cross-linked by nano VCB. The addition of nano VCB significantly increased gelatin film strength with the greatest tensile strength of 52.589 MPa and stiffness with the highest Young's modulus of 968.874 MPa, but led to the reduction of film elongation. Also, the VCB presence significantly improved water vapour and oxygen barrier properties of GEL film. Importantly, nano VCB increased GEL film with better UV barrier property due to its stronger UV absorption nature when compared with micron VCB. This property could help in the preservation of oil samples in the photooxidation accelerated test. CONCLUSION: With improved properties, the nano VCB-reinforced GEL film may have great potential for application in the edible packaging field, especially for the anti-photooxidation property. © 2017 Society of Chemical Industry.
Asunto(s)
Proteínas de Peces/química , Embalaje de Alimentos/instrumentación , Gelatina/química , Gelatina/efectos de la radiación , Verduras/química , Animales , Peces , Permeabilidad , Fotólisis , Solubilidad , Resistencia a la TracciónRESUMEN
The aim of this study was to investigate the efficacy of power ultrasound without using any heating stage in solubilizeing gelatin dispersions, and to characterize the mechanical and microstructural properties of the resulting gels using texture analysis and scanning electron microscopy, respectively. Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. For solubilising gelatin, an ultrasound equipment with a frequency of 20 kHz, amplitude of 100% and power range of 50-150 W was used. Aqueous gelatin dispersions (4% w/v) were subjected to ultrasound for different times (40-240 s) at a constant temperature of 13C. Applying ultrasound to gelatin dispersions caused increases in water absorption and water solubility of the hydrocolloid. The textural parameters of the resulting gelatin gels, increased with increasing time and power of ultrasound. Moreover, a generalized Maxwell model with three elements was used for calculating relaxation times of the gels. The microstructural observations by SEM showed that the structural cohesiveness of the gels increased by increasing ultrasonication time. Ultrasound-assisted solubilization of gelatin can have emerging implications for industrial uses in pharmaceuticals, food and non-food systems. PRACTICAL APPLICATIONS: Usually to prepare a gel from gelatin, a primary heating stage of at about 40C or above is required to solubilize gelatin macromolecules. Therefore, the use of gelatin as a hydrocolloid in food processings or pharmaceutical formulations which lack a heating step has been a technological and practical challenge. In this study solubilizing gelatin dispersions using power ultrasound without any heating was successfully performed. Ultrasound-assisted solubilisation of gelatin can have emerging implications for industrial uses in pharmaceuticals, food, and non-food systems, for example, to conserve heat sensitive compounds.
Asunto(s)
Gelatina/química , Gelatina/efectos de la radiación , Geles/química , Calefacción , Ondas Ultrasónicas , Animales , Bovinos , Composición de Medicamentos/métodos , Manipulación de Alimentos/métodos , Microscopía Electrónica de Rastreo , Solubilidad , Temperatura , Viscosidad , Agua/químicaRESUMEN
The first derivatives of gelatin and type I collagen fluorescence spectra were characterized in order to describe the effect of free radicals on pyridinoline (PYD) cross-links. The different gas saturation conditions were used to investigate the effect of different free radicals. An analysis of first derivative fluorescence spectra suggests that PYD cross-link fluorescence emission is composed of three peaks in gelatin, but only two in type I collagen. The PYD cross-link was photo-degraded more than other gases in the presence of O2. This suggests that the singlet oxygen ((1)O2) plays a key role when using photodynamic therapy to treat skin fibrosis disease with Hypocrellin B (HB).
Asunto(s)
Aminoácidos/química , Colágeno Tipo I/química , Gelatina/química , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/química , Oxígeno Singlete/química , Enfermedades de la Piel/tratamiento farmacológico , Piel/efectos de los fármacos , Aminoácidos/efectos de la radiación , Colágeno Tipo I/efectos de la radiación , Fibrosis , Gelatina/efectos de la radiación , Humanos , Radical Hidroxilo/química , Fotólisis , Fármacos Fotosensibilizantes/farmacología , Proteolisis , Piel/metabolismo , Piel/patología , Enfermedades de la Piel/metabolismo , Enfermedades de la Piel/patología , Espectrometría de FluorescenciaRESUMEN
In vitro engineering of autologous fatty tissue constructs is still a major challenge for the treatment of congenital deformities, tumor resections or high-graded burns. In this study, we evaluated the suitability of photo-crosslinkable methacrylated gelatin (GM) and mature adipocytes as components for the composition of three-dimensional fatty tissue constructs. Cytocompatibility evaluations of the GM and the photoinitiator Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) showed no cytotoxicity in the relevant range of concentrations. Matrix stiffness of cell-laden hydrogels was adjusted to native fatty tissue by tuning the degree of crosslinking and was shown to be comparable to that of native fatty tissue. Mature adipocytes were then cultured for 14 days within the GM resulting in a fatty tissue construct loaded with viable cells expressing cell markers perilipin A and laminin. This work demonstrates that mature adipocytes are a highly valuable cell source for the composition of fatty tissue equivalents in vitro. Photo-crosslinkable methacrylated gelatin is an excellent tissue scaffold and a promising bioink for new printing techniques due to its biocompatibility and tunable properties.
Asunto(s)
Adipocitos/citología , Tejido Adiposo/crecimiento & desarrollo , Gelatina/química , Metacrilatos/química , Ingeniería de Tejidos/instrumentación , Andamios del Tejido , Adipocitos/fisiología , Tejido Adiposo/citología , Materiales Biocompatibles/síntesis química , Células Cultivadas , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Diseño de Equipo , Análisis de Falla de Equipo , Gelatina/efectos de la radiación , Humanos , Luz , Ensayo de Materiales , Metacrilatos/efectos de la radiación , Técnicas de Cultivo de Órganos/instrumentación , Ingeniería de Tejidos/métodosRESUMEN
Biofunctional scaffolds that support the adhesion, proliferation, and osteo-differentiation of mesenchymal stem cells (MSCs) are critical for bone tissue engineering. In this study, a simple in situ UV-crosslinking strategy was utilized to fabricate gelatin electrospun fibrous (GEF) scaffolds with multiple biosignals, including cell adhesive Arg-Gly-Asp (RGD) peptide, osteo-conductive hydroxyapatite (HAp) nanoparticles, and osteo-inductive bone morphogenic protein-2 (BMP-2). The adhesion and proliferation of MSCs on the GEF scaffolds were improved by the incorporation of RGD. Meanwhile, the incorporation of HAp and BMP-2 enhanced osteo-differentiation of MSCs. The three incorporated bio-factors exert a synergistic effect on osteogenesis of MSCs in the GEF scaffolds. This strategy of incorporating multiple biomolecules could be used to fabricate crosslinked electrospun scaffolds of natural polymers for tissue-engineering applications.
Asunto(s)
Gelatina/química , Células Madre Mesenquimatosas/citología , Osteogénesis/fisiología , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Fosfatasa Alcalina/metabolismo , Animales , Proteína Morfogenética Ósea 2/química , Proteína Morfogenética Ósea 2/metabolismo , Proteína Morfogenética Ósea 2/farmacología , Calcio/metabolismo , Adhesión Celular/efectos de los fármacos , Adhesión Celular/fisiología , Línea Celular , Durapatita/química , Durapatita/metabolismo , Durapatita/farmacología , Técnicas Electroquímicas/métodos , Gelatina/metabolismo , Gelatina/efectos de la radiación , Humanos , Células Madre Mesenquimatosas/metabolismo , Nanopartículas/química , Nanopartículas/metabolismo , Oligopéptidos/química , Oligopéptidos/metabolismo , Oligopéptidos/farmacología , Osteogénesis/efectos de los fármacos , Reproducibilidad de los Resultados , Rayos UltravioletaRESUMEN
The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino acids. No modification of the crystallinity of the film is observed. These findings suggest that if structure changes, it only occurs in the amorphous phase of the gelatin matrix. It is also observed that irradiation enhances the thermal stability of the gelatin film, by increasing the glass transition temperature and the degradation temperature.
Asunto(s)
Electrones , Gelatina/efectos de la radiación , Animales , Rastreo Diferencial de Calorimetría , Peces , Radicales Libres , Gelatina/química , Propiedades de Superficie , Agua/químicaRESUMEN
Photocrosslinkable hydrogels are frequently used in cartilage tissue engineering, with crosslinking systems relying on cytotoxic photoinitiators and ultraviolet (UV) light to form permanent hydrogels. These systems are rarely assessed in terms of optimization of photoinitiator or UV dosage, with non-cytotoxic concentrations from literature deemed sufficient. We hypothesized that the number of reactive functional groups present within a hydrogel polymer is highly relevant when crosslinking, affording cytoprotection to chondrocytes by preferentially interacting with the highly reactive radicals that are formed during UV-mediated activation of a photoinitiator. This was tested using two photocrosslinkable hydrogel systems: gelatin methacrylamide (GelMA) and gellan gum methacrylate (GGMA). We further assessed the effects of two different UV dosages on chondrocyte differentiation while subject to a single photoinitiator dosage in the GGMA system. Most notably, we found that a higher ratio of reactive groups to photoinitiator molecules offers cytoprotective effects, and future developments in photocrosslinkable hydrogel technology may involve assessment of such ratios. In contrast, we found there to be no effect of UV on chondrocyte differentiation at the two chosen dosages. Overall the optimization of photocrosslinkable systems is of great value in cartilage tissue engineering and these data provide a groundwork for such concepts to be developed further. STATEMENT OF SIGNIFICANCE: Photocrosslinkable hydrogels, which use photoinitiators and predominantly ultraviolet light to form stable matrices for cell encapsulation and tissue development, are promising for cartilage tissue engineering. While both photoinitiators and ultraviolet light can damage cells, these systems have generally not been optimized. We propose that the ratio of reactive functional groups within a polymer to photoinitiator molecules is a critical parameter for optimization of photocrosslinkable hydrogels. Using photocrosslinkable gelatin and gellan gum, we found that a higher ratio of reactive groups to photoinitiator molecules protected chondrocytes, but did not affect chondrocyte differentiation. The principle of cytoprotection by functional groups developed in this work will be of great value in optimizing photocrosslinkable hydrogel systems for cartilage and other tissue engineering applications.
Asunto(s)
Condrocitos/efectos de los fármacos , Reactivos de Enlaces Cruzados/química , Hidrogeles/química , Hidrogeles/toxicidad , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Condrocitos/patología , Reactivos de Enlaces Cruzados/efectos de la radiación , Citoprotección/fisiología , Citoprotección/efectos de la radiación , Relación Dosis-Respuesta a Droga , Gelatina/química , Gelatina/efectos de la radiación , Gelatina/toxicidad , Humanos , Hidrogeles/efectos de la radiación , Metacrilatos/química , Metacrilatos/efectos de la radiación , Metacrilatos/toxicidad , Fotoquímica/métodos , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/efectos de la radiación , Polisacáridos Bacterianos/toxicidad , Dosis de Radiación , Rayos UltravioletaRESUMEN
Modular tissue engineering holds great potential in regenerating natural complex tissues by engineering three-dimensional modular scaffolds with predefined geometry and biological characters. In modular tissue-like construction, a scaffold with an appropriate mechanical rigidity for assembling fabrication and high biocompatibility for cell survival is the key to the successful bioconstruction. In this work, a series of composite hydrogels (GH0, GH1, GH2, and GH3) based on a combination of methacrylated gelatin (GelMA) and hydroxyapatite (HA) was exploited to enhance hydrogel mechanical rigidity and promote cell functional expression for osteon biofabrication. These composite hydrogels presented a lower swelling ratio, higher mechanical moduli, and better biocompatibility when compared to the pure GelMA hydrogel. Furthermore, on the basis of the composite hydrogel and photolithograph technology, we successfully constructed an osteon-like concentric double-ring structure in which the inner ring encapsulating human umbilical vascular endothelial cells (HUVECs) was designed to imitate blood vessel tubule while the outer ring encapsulating human osteoblast-like cells (MG63s) acts as part of bone. During the coculture period, MG63s and HUVECs exhibited not only satisfying growth status but also the enhanced genic expression of osteogenesis-related and angiogenesis-related differentiations. These results demonstrate this GelMA-HA composite hydrogel system is promising for modular tissue engineering.
Asunto(s)
Sustitutos de Huesos/síntesis química , Durapatita/química , Osteón/química , Metacrilatos/química , Osteoblastos/fisiología , Andamios del Tejido , Materiales Biomiméticos/química , Línea Celular , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Durapatita/efectos de la radiación , Diseño de Equipo , Análisis de Falla de Equipo , Gelatina/química , Gelatina/efectos de la radiación , Osteón/ultraestructura , Humanos , Hidrogeles/química , Hidrogeles/efectos de la radiación , Luz , Ensayo de Materiales , Nanoconjugados/química , Nanoconjugados/efectos de la radiación , Nanoconjugados/ultraestructura , Osteoblastos/citología , Osteogénesis/fisiología , Ingeniería de Tejidos/instrumentaciónRESUMEN
A layered gelatin-chitosan hydrogel with graded composition was prepared via photocrosslinking to simulate the polysaccharide/collagen composition of the natural tissue and mimic the multi-layered gradient structure of the cartilage-bone interface tissue. Firstly, gelatin and carboxymethyl chitosan were reacted with glycidyl methacrylate (GMA) to obtain methacrylated gelatin (Gtn-GMA) and carboxymethyl chitosan (CS-GMA). Then, the mixed solutions of Gtn-GMA in different methacrylation degrees with CS-GMA were prepared to form the superficial, transitional and deep layers of the hydrogel, respectively under the irradiation of ultraviolet light, while polyhedral oligomeric silsesquioxane was introduced in the deep layer to improve the mechanical properties. Results suggested that the pore sizes of the superficial, transitional and deep layers of the layered hydrogel were 115 ± 30, 94 ± 34, 51 ± 12 µm, respectively and their porosities were all higher than 80 %. The compressive strengths of them were 165 ± 54, 565 ± 50 and 993 ± 108 kPa, respectively and the strain of the gradient hydrogel decreased along the thickness direction, similar to the natural tissue. The in vitro cytotoxicity results showed that the hydrogel had good cytocompatibility and the in vivo repair results of osteochondral defect demonstrated remarkable recovery by using the gradient gelatin-chitosan hydrogel, especially when the hydrogel loading transforming growth factor-ß1. Therefore, it was suggested that the prepared layered gelatin-chitosan hydrogel in this study could be potentially used to promote cartilage-bone interface tissue repair.
Asunto(s)
Materiales Biomiméticos/química , Quitosano/química , Quitosano/uso terapéutico , Fracturas del Cartílago/terapia , Gelatina/química , Hidrogeles/química , Animales , Materiales Biomiméticos/uso terapéutico , Quitosano/efectos de la radiación , Fuerza Compresiva , Reactivos de Enlaces Cruzados/química , Reactivos de Enlaces Cruzados/efectos de la radiación , Fracturas del Cartílago/patología , Gelatina/efectos de la radiación , Gelatina/uso terapéutico , Hidrogeles/efectos de la radiación , Hidrogeles/uso terapéutico , Luz , Ensayo de Materiales , Fotoquímica , Porosidad , Conejos , Resultado del TratamientoRESUMEN
Sterilization through γ-irradiation has been reported to affect collagen mechanical properties, but its possible effects on gelatin based materials have not been investigated up to now. Herein we report the results of a mechanical, chemical and thermal study performed on gelatin films before and after γ-irradiation. The investigation was performed on uncrosslinked films as well as on crosslinked films. To this aim, two common crosslinking agents, glutaraldehyde and genipin, at different concentration (0.15, 0.30 and 0.67%) were used. The results indicate that sterilization significantly affects the mechanical properties of uncrosslinked films, whereas it displays a modest effect on gelatin swelling, release in solution, thermal stability and molecular structure. Both glutaraldehyde and genipin enhance the mechanical properties and stability in solution of the gelatin films. In particular, the values of Young modulus increase as a function of crosslinker concentration up to about 10 and 18 MPa for genipin and glutaraldehyde treated samples respectively. The results of in vitro study demonstrate that the films crosslinked with genipin do not display any cytotoxic reaction, whereas glutaraldehyde crosslinking provokes an acute and dose dependent cytotoxic effect.