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Carboxymethylcellulose (CMC) and keratin nanoparticle (KNP) hydrogels were obtained, characterized, and applied as drug delivery systems (DDSs) for the first time. Lyophilized CMC/KNP mixtures containing 10, 25, and 50 wt% of KNPs were kept at 170 °C for 90 min to crosslink CMC chains through a solid-state reaction with the KNPs. The hydrogels were characterized by infrared spectroscopy, thermal analyses, X-ray diffraction, mechanical measurements, and scanning electron microscopy. The infrared spectra indicated the formation of ester and amide linkages between crosslinked CMC and KNPs. The elastic modulus of the hydrogel containing 10 wt% KNPs was 2-fold higher than that of the hydrogel containing 50 wt% KNPs. The mechanical properties influenced the hydrogel stability and water uptake. The anti-inflammatory prednisolone (PRED) drug was incorporated into the hydrogels, and the release mechanism was investigated. The hydrogels supported PRED release by drug desorption for approximately 360 h. A sustained release mechanism was achieved. The CMC/KNP and CMC/KNP/PRED hydrogels were cytocompatible toward mammalian cells. The CMC/KNP/PRED set imparted the highest cell viability after 7 days of incubation. This study showed a straightforward procedure to create DDSs (chemically crosslinked) based on polysaccharides and proteins for efficient PRED delivery.
Assuntos
Hidrogéis , Nanopartículas , Animais , Hidrogéis/química , Queratinas , Carboximetilcelulose Sódica/química , Prednisolona/farmacologia , Anti-Inflamatórios , MamíferosRESUMO
This study aims to characterize a new Ti-25Ta-25Nb-5Sn alloy for biomedical application. Microstructure, phase formation, mechanical and corrosion properties, along with the cell culture study of the Ti-25Ta-25Nb alloy with Sn content 5 mass% are presented in this article. The experimental alloy was processed in an arc melting furnace, cold worked, and heat treated. For characterization, optical microscopy, X-ray diffraction, microhardness, and Young's modulus measurements were employed. Corrosion behavior was also evaluated using open-circuit potential (OCP) and potentiodynamic polarization. In vitro studies with human ADSCs were performed to investigate cell viability, adhesion, proliferation, and differentiation. Comparison among the mechanical properties observed in other metal alloy systems, including CP Ti, Ti-25Ta-25Nb, and Ti-25Ta-25-Nb-3Sn showed an increase in microhardness and a decrease in the Young's modulus when compared to CP Ti. The potentiodynamic polarization tests indicated that the corrosion resistance of the Ti-25Ta-25Nb-5Sn alloy was similar to CP Ti and the experiments in vitro demonstrated great interactions between the alloy surface and cells in terms of adhesion, proliferation, and differentiation. Therefore, this alloy presents potential for biomedical applications with properties required for good performance.
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The study of new metallic biomaterials for application in bone tissue repair has improved due to the increase in life expectancy and the aging of the world population. Titanium alloys are one of the main groups of biomaterials for these applications, and beta-type titanium alloys are more suitable for long-term bone implants. The objective of this work was to process and characterize a new Ti10Mo8Nb6Zr beta alloy. Alloy processing involves arc melting, heat treatment, and cold forging. The characterization techniques used in this study were X-ray fluorescence spectroscopy, X-ray diffraction, differential scanning calorimetry, optical microscopy, microhardness measurements, and pulse excitation technique. In vitro studies using adipose-derived stem cells (ADSC) were performed to evaluate the cytotoxicity and cell viability after 1, 4, and 7 days. The results showed that the main phase during the processing route was the beta phase. At the end of processing, the alloy showed beta phase, equiaxed grains with an average size of 228.7 µm, and low Young's modulus (83 GPa). In vitro studies revealed non-cytotoxicity and superior cell viability compared to CP Ti. The addition of zirconium led to a decrease in the beta-transus temperature and Young's modulus and improved the biocompatibility of the alloy. Therefore, the Ti10Mo8Nb6Zr alloy is a promising candidate for application in the biomedical field.
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Ideal wound dressings should be biocompatible, exhibit high antibacterial activity, and promote blood coagulation. To impart these imperative functions, carboxymethyl-kappa-carrageenan was incorporated into poly(vinyl alcohol) nanofibers (PVA-CMKC). The antibacterial activity of the nanofibers was evaluated. Adsorption of two important blood proteins, fibrinogen and albumin, was also assessed. The adhesion and activation of platelets, and the clotting of whole blood were evaluated to characterize the ability of the nanofibers to promote hemostasis. Adhesion and morphology of both Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using fluorescence microscopy and scanning electron microscopy. CMKC-containing nanofibers demonstrated significant increases in platelet adhesion and activation, percentage of coagulation in whole blood clotting test and fibrinogen adsorption, compared to PVA nanofibers, showing blood coagulation activity. Incorporating CMKC also reduces adhesion and viability of S. aureus and P. aeruginosa bacteria after 24 h of incubation. PVA-CMKC nanofibers show potential application as dressings for wound healing applications.
Assuntos
Antibacterianos/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Carragenina/farmacologia , Nanofibras/química , Cicatrização/efeitos dos fármacos , Albuminas/metabolismo , Antibacterianos/química , Bandagens , Materiais Biocompatíveis/farmacologia , Carragenina/química , Fibrinogênio/metabolismo , Humanos , Microscopia Eletrônica de Varredura/métodos , Ativação Plaquetária/efeitos dos fármacos , Álcool de Polivinil/química , Álcool de Polivinil/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacosRESUMO
In this work free-standing gels formed from gellan gum (GG) by solvent evaporation are coated with polysaccharide-based polyelectrolyte multilayers, using the layer-by-layer approach. We show that PEMs composed of iota-carrageenan (CAR) and three different natural polycationic polymers have composition-dependent antimicrobial properties, and support mammalian cell growth. Cationic polymers (chitosan (CHT), N,N,N-trimethyl chitosan (TMC), and an amino-functionalized tannin derivative (TN)) are individually assembled with the anionic iota-carrageenan (CAR) at pH 5.0. PEMs (15-layers) are alternately deposited on the GG film. The GG film and coated GG films with PEMs are characterized by infrared spectroscopy with attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle (WCA) measurements. The TN/CAR coating provides a hydrophobic (WCA = 127°) and rough surface (Rq = 243 ± 48 nm), and the TMC/CAR coating provides a hydrophilic surface (WCA = 78°) with the lowest roughness (Rq = 97 ± 12 nm). Polymer coatings promote stability and durability of the GG film, and introduce antimicrobial properties against Gram-negative (Salmonella enteritidis) and Gram-positive (Staphylococcus aureus) bacteria. The films are also cytocompatible. Therefore, they have properties that can be further developed as wound dressings and food packaging.
Assuntos
Anti-Infecciosos/síntese química , Materiais Biocompatíveis/síntese química , Carragenina/química , Quitosana/química , Polissacarídeos Bacterianos/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Embalagem de Alimentos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Microscopia de Força Atômica , Espectroscopia Fotoeletrônica , Polieletrólitos , CicatrizaçãoRESUMO
This study presents a new type of biocompatible nanofiber based on poly(vinyl alcohol) (PVA) and carboxymethyl-kappa-carrageenan (CMKC) blends, produced with no generation of hazardous waste. The nanofibers are produced by electrospinning using PVA:CMKC blends with ratios of 1:0, 1:0.25, 1:0.4, 1:0.5, and 1:0.75 (w/w PVA:CMKC) in aqueous solution, followed by thermal crosslinking. The diameter of the fibers is in the nanometer scale and below 300 nm. Fourier transform infrared spectroscopy shows the presence of the carboxyl and sulfate groups in all the fibers with CMKC. The nanofibers from water-soluble polymers are stabilized by thermal crosslinking. The incorporation of CMKC improves cytocompatibility, biodegradability, cell growth, and cell adhesion, compared to PVA nanofibers. Furthermore, the incorporation of CMKC modulates phenotype of human adipose-derived stem cells (ADSCs). PVA/CMKC nanofibers enhance ADSC response to osteogenic differentiation signals and are therefore good candidates for application in tissue engineering to support stem cells.
Assuntos
Materiais Biocompatíveis/farmacologia , Nanofibras/química , Osteogênese/efeitos dos fármacos , Engenharia Tecidual , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Carragenina/química , Carragenina/farmacologia , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Microscopia Eletrônica de Varredura , Álcool de Polivinil/química , Álcool de Polivinil/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Alicerces Teciduais/químicaRESUMO
Pectin and chitosan films containing glycerol (Gly) at 5, 10, 15, 20, 30, and 40 wt % were prepared in an aqueous HCl solution (0.10 M) by the solvent evaporation method. The unwashed film (UF) containing 40 wt % Gly (UF40) had elongation at break (ε, %) of 19%. Washed films (WFs) had high tensile strength (σ > 46 MPa) and low elongation at break (ε, <5.0%), enabling their use in food packaging applications. The polymers' self-assembling occurred during the washing, increasing the stiffness. The XPS analysis suggests that some HCl is lost during the drying process, resulting in a low acid content on the UF surfaces. The UF40 (at 5.0 mg/mL) exhibits cytocompatibility toward mammalian cells and antimicrobial and anti-adhesive properties against Escherichia coli. The remaining HCl in the UF40 can be a disadvantage for food packaging applications; the UF40 (∅ = 8.5 mm; 55 µm thickness) releases H3O+/HCl, reducing the pH to approximately 3.0 when kept in 200 mL distilled water for approximately 30 min. Therefore, we propose the use of UF40 to coat commercial food packaging. The UF40 has low permeability to water vapor and oxygen and works as a barrier against ultraviolet light. The UF40 is also colorless and completely transparent. The UF40 maintained tomatoes' structural integrity for 18 days at room temperature with no oxidation or microorganism contamination. This paper presents a critical viewpoint concerning chitosan-based films with antimicrobial activities.
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Antibacterianos/química , Quitosana/química , Materiais Revestidos Biocompatíveis/química , Escherichia coli/crescimento & desenvolvimento , Embalagem de Alimentos , Glicerol/química , Membranas Artificiais , Pectinas/químicaRESUMO
Titanium and titanium alloys are widely used as a biomaterial due to their mechanical strength, corrosion resistance, low elastic modulus, and excellent biocompatibility. TiO2 nanotubes have excellent bioactivity, stimulating the adhesion, proliferation of fibroblasts and adipose-derived stem cells, production of alkaline phosphatase by osteoblasts, platelets activation, growth of neural cells and adhesion, spreading, growth, and differentiation of rat bone marrow mesenchymal stem cells. In this study, we investigated the functionality of fibroblast on titania nanotube layers annealed at different temperatures. The titania nanotube layer was fabricated by potentiostatic anodization of titanium, then annealed at 300, 530, and 630 °C for 5 h. The resulting nanotube layer was characterized using SEM (Scanning Electron Microscopy), TF-XRD (Thin-film X-ray diffraction), and contact angle goniometry. Fibroblasts viability was determined by the CellTiter-Blue method and cytotoxicity by Lactate Dehydrogenase test, and the cell morphology was analyzed by scanning electron microscopy. Also, cell adherence, proliferation, and morphology were analyzed by fluorescence microscopy. The results indicate that the modification in nanotube crystallinity may provide a favorable surface fibroblast growth, especially on substrates annealed at 530 and 630 °C, indicating that these properties provide a favorable template for biomedical implants.
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Fibroblastos/metabolismo , Nanotubos/química , Titânio/química , Animais , Materiais Biocompatíveis/química , Células da Medula Óssea/citologia , Adesão Celular , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células , Sobrevivência Celular , Cristalização , Citoesqueleto/metabolismo , Células-Tronco Mesenquimais/citologia , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Osteoblastos/citologia , Próteses e Implantes , Ratos , Células-Tronco/citologiaRESUMO
The polymer poly(ε-caprolactone) (PCL) has been used in the biomaterial field for its relatively inexpensive price and suitability for modification. Also, its chemical and biological properties are desirable for biomedical applications. The electrospinning process has been used for producing polymer fibers of PCL due in large part to an increased interest in nanoscale properties and technologies. Moreover, the use of biocompatible polymers for the viability of cell growth is a promising alternative to improve osseointegration. Characterization techniques such as scanning electron microscopy and contact angle were used for analyses of samples. Adult human dermal fibroblasts (neonatal) were utilized to evaluate the biocompatibility of the association of the electrospinning process of the biocompatible polymer (PCL) with TiO2 nanotubes on the Ti-30Ta alloy surface. The results of this study showed a favorable response for adhesion on the surface. This promising material is due to the modulation of the biological response.
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Fibroblastos/efeitos dos fármacos , Nanofibras , Nanotubos , Tantálio , Titânio/farmacologia , Ligas , Materiais Biocompatíveis , Caproatos , Humanos , Lactonas , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura , Polímeros , Pele/citologia , Pele/efeitos dos fármacos , Titânio/químicaRESUMO
To obtain pectin-based films is challenging due to the aqueous instability of polyelectrolyte mixtures. We overcome this issue by blending chitosan to pectin of high O-methoxylation degree (56%), followed by solvent evaporation. A durable film containing 74 wt% pectin content was produced and used as an adsorbent material toward Cu(II) ions. Kinetic and adsorption equilibrium studies showed that the pseudo-second-order and Sips isotherm models adjusted well to the experimental data, respectively. Langmuir isotherm indicated a maximum adsorption capacity (qm) for Cu(II) removal of 29.20 mg g-1. Differential scanning calorimetry, contact angle measurements, and X-ray photoelectron spectroscopy confirm the adsorption. The chemisorption plays an essential role in the process; thereby, the film reusability is low. After adsorption, the cytocompatible film/Cu(II) pair prevents the proliferation of Escherichia coli.
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Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Cobre/química , Cobre/isolamento & purificação , Pectinas/química , Pectinas/farmacologia , Água/química , Adsorção , Quitosana/química , Escherichia coli/efeitos dos fármacos , Cinética , Teste de Materiais , Metilação , SoluçõesRESUMO
Chemical modification of polysaccharides is an important route to enhance, develop or change polysaccharide properties. In this study, carboxymethylation of kappa-carrageenan (KC) with monochloroacetic acid was performed to achieve different degrees of substitution (DS) of carboxymethyl-kappa-carrageenan (CMKC). The degree of substitution ranged from 0.8 to 1.6 and was calculated from the 1H NMR spectra. The chemical structure of the CMKCs was further characterized by FT-IR, and 13C NMR. FT-IR confirmed the carboxymethylation. Carboxymethylation increased viscosity of KC in water and decreased viscosity of KC in synthetic human sweat. Tests with human adipose derived stem cells showed higher viability and lower cytotoxicity for CMKCs when compared to KC. CMKCs showed no hemolytic activity to human red blood cells. CMKCs have increased antioxidant activity compared to KC. In antibacterial assays, CMKCs with DS of 0.8, 1.0 and 1.2 exhibited growth inhibition against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. CMKC with DS ranging from 1.0 to 1.2 are good candidate biomaterials for cell-contacting applications.
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Antibacterianos/química , Antioxidantes/química , Materiais Biocompatíveis/química , Carragenina/química , Acetatos/química , Adipócitos/citologia , Tecido Adiposo/citologia , Bacillus cereus , Sobrevivência Celular , Escherichia coli , Sequestradores de Radicais Livres , Hemólise , Humanos , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Polímeros/química , Polissacarídeos/química , Pseudomonas aeruginosa , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus , Células-Tronco/citologiaRESUMO
Studies report the production of gold nanoparticles (AuNPs) and polysaccharides-based composites. However, there are few reports about AuNPs synthesis in-situ followed by the formation of hydrogel composites. Here, we show AuNPs synthesis in-situ into the pectin solutions to yield cytocompatible pectin-capped AuNPs/chitosan hydrogel composites. Visible spectroscopy and dynamic light scattering measurements confirm the AuNPs synthesis. The hydrodynamic radius of the pectin-capped AuNPs ranges from approximately 510 to 721 nm, while the Zeta potential is around -43 mV. Scanning electron microscopy shows that the composites present compact structures. Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy characterize the composites as well. Hydrogels (with or without AuNPs) containing the highest pectin content (at 4.12 pectin/chitosan weight ratio) have low stability (disintegrates approximately 60% after 14 days in phosphate buffer). Composites obtained at 3.75 pectin/chitosan weight ratio disintegrate between 25 and 30% after 14 days in phosphate buffer (physiological condition = pH 7.4). The AuNPs reinforce the hydrogel structures, increasing the elastic modulus (from 3.5 to 7.6 Pa) and decreasing the water uptake from 4465 to 2976%. 3.75 PT/CS weight ratio and 3.0 × 10-4 M Au(III) content provide a durable, cytocompatible, and superabsorbent hydrogel composite. These properties can support materials for drug delivery purposes.
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Absorção Fisico-Química , Quitosana/química , Ouro/química , Hidrogéis/química , Nanopartículas Metálicas/química , Pectinas/química , Tecido Adiposo/citologia , Animais , Morte Celular , Sobrevivência Celular , Espectroscopia Fotoeletrônica , Polieletrólitos/química , Espectrofotometria Ultravioleta , Células-Tronco/citologiaRESUMO
This study reports the synthesis, characterization and biological properties of films based on poly(vinyl alcohol) (PVA) and a cationic tannin polymer derivative (TN). Films are obtained from polymeric blends by tuning the PVA/TN weight ratios. The materials are characterized through infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle measurements, mechanical analyses, and scanning electron microscopy. More hydrophilic surfaces are created by modulating the PVA and TN concentrations in the blends. Disintegration tests showed that the films present durability in phosphate buffer (pH 7.4) and low stability in simulated gastric fluid (pH 1.2). The film created at 90/10 PVA/TN weight ratio and crosslinked at 109 PVA/glutaraldehyde molar ratio (sample PVA10/TN10) supports the attachment and proliferation of bone marrow mesenchymal stem cells after 7 days of culture. The scaffolding capacity of the PVA10/TN10 surface is compared with titanium, one of the most important biomedical materials used in bone replacements. Also, the PVA/TN films exhibited cytocompatibility, antioxidant and antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. These properties make PVA/TN films are candidates for biomedical applications in the tissue engineering field.
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Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Materiais Biocompatíveis/química , Taninos/farmacocinética , Animais , Antibacterianos/química , Antioxidantes/farmacocinética , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Reagentes de Ligações Cruzadas/química , Glutaral/química , Hidrogéis/síntese química , Hidrogéis/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Masculino , Teste de Materiais , Células-Tronco Mesenquimais/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Espectroscopia Fotoeletrônica , Álcool de Polivinil/química , Pseudomonas aeruginosa/efeitos dos fármacos , Ratos Wistar , Staphylococcus aureus/efeitos dos fármacos , Taninos/químicaRESUMO
Here, we have demonstrated the production and characterization of hydrogel scaffolds based on chitosan/gellan gum (CS/GG) assemblies, without any covalent and metallic crosslinking agents, conventionally used to yield non-soluble polysaccharide-based materials. The polyelectrolyte complexes (physical hydrogels called as PECs) are characterized by Fourier-transform infrared spectroscopy, wide-angle X-ray scattering, and scanning electron microscopy. Hydrogels containing chitosan (CS) excesses (ranging from 60 to 80â¯wt%) were created. Durable polysaccharide-based scaffolds with structural homogeneity and interconnecting pore networks are developed by modulating the CS/GG weight ratio. The CS/GG hydrogel prepared at 80/20 CS/GG weight ratio (sample CS/GG80-20) is cytocompatible, supporting the attachment, growth, and spreading of bone marrow mesenchymal stem cells (BMSCs) after nine days of cell culture. The cytocompatibility is correlated to the swelling capacity of the PEC in PBS buffer (pH 7.4). By controlling the CS content, we can tune the water uptake of the material, enhancing the capacity to serve as a three-dimensional cell scaffold for BMSCs. This work presents for the first time that CS/GG hydrogels can be applied as scaffolds for tissue engineering purposes.
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Materiais Biocompatíveis/química , Quitosana/química , Hidrogéis/química , Células-Tronco Mesenquimais/citologia , Polissacarídeos Bacterianos/química , Animais , Materiais Biocompatíveis/farmacologia , Humanos , Masculino , Células-Tronco Mesenquimais/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Ratos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Engenharia Tecidual/métodosRESUMO
The periosteum is a membrane that surrounds bones, providing essential cellular and biological components for fracture healing and bone repair. Tissue engineered scaffolds able to function as periosteum substitutes can significantly improve bone regeneration in severely injured tissues. Efforts to develop more bioactive and tunable periosteal substitutes are required to improve the success of this tissue engineering approach. In this work, a chemical modification was performed in chitosan, a polysaccharide with osteoconductive properties, by introducing phosphate groups to its structure. The phosphorylated polymer (Chp) was used to produce chitosan-xanthan-based scaffolds for periosteal tissue engineering. Porous and mechanically reinforced matrices were obtained with addition of the surfactant Kolliphor® P188 and the silicone rubber Silpuran® 2130A/B. Scaffolds properties, such as large pore sizes (850-1097 µm), micro-roughness and thickness (0.7-3.5 mm in culture medium), as well as low thrombogenicity compared to standard implantable materials, extended degradation time and negligible cytotoxicity, enable their application as periosteum substitutes. Moreover, the higher adsorption of bone morphogenetic protein mimic (cytochrome C) by Chp-based formulations suggests improved osteoinductivity of these materials, indicating that, when used in vivo, the material would be able to concentrate native BMPs and induce osteogenesis. The scaffolds produced were not toxic to adipose tissue-derived stem cells, however, cell adhesion and proliferation on the scaffolds surfaces can be still further improved. The mineralization observed on the surface of all formulations indicates that the materials studied have promising characteristics for the application in bone regeneration.
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Quitosana/farmacologia , Osseointegração/efeitos dos fármacos , Periósteo/fisiologia , Polissacarídeos Bacterianos/farmacologia , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Tecido Adiposo/citologia , Adsorção , Fosfatase Alcalina/metabolismo , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Células Cultivadas , Citocromos c/metabolismo , Módulo de Elasticidade , Humanos , L-Lactato Desidrogenase/metabolismo , Muramidase/metabolismo , Osteogênese/efeitos dos fármacos , Periósteo/efeitos dos fármacos , Fosforilação , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Estresse Mecânico , Trombose/patologiaRESUMO
Physical kappa-carrageenan-based hydrogels are often prepared from dilute aqueous kappa-carrageenan (κ-carrageenan) solutions at the presence of metallic ions or by mixing these solutions with proteins and other polysaccharides. The κ-carrageenan hydrogels have been used for technological purposes; however, there are no reports about the properties of a commercial GENUGEL® κ-carrageenan produced by the CP Kelco. The flame atomic absorption spectrometry shows that the commercial κ-carrageenan comprises a high content of metallic ions (K+ = 216.1 g kg-1, Na+ = 6.3 g kg-1 and Ca2+ = 12.5 g kg-1). The X-ray photoelectron spectroscopy (XPS) indicates the presence of sodium, calcium, and potassium atoms on the as-received κ-carrageenan and its physical hydrogel surfaces. XPS supports the occurrence of a low protein content onto the sample surfaces, as well. The metallic level (especially for K+) in the commercial κ-carrageenan plays an essential role in the preparation of durable hydrogels. These materials are prepared by cooling aqueous κ-carrageenan solutions at 4.0 and 5.0 wt%. The gelation temperature is determined by measuring G' &Gâ³ as a function of the temperature. The gelation behavior depends on the κ-carrageenan concentration, as well as the metallic content in the commercial sample. Scanning electron microscopy shows that hydrogels have porous and smooth surfaces. The dried materials swell from 2400 to 3100%, while the disintegration/dissolution test confirms that the samples present high stability in distilled water throughout 14 days. These hydrogels are superabsorbent materials and can be applied in agriculture as soil conditioners.
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Carragenina/química , Ingredientes de Alimentos/análise , Hidrogéis/química , Tamanho da Partícula , Espectrofotometria Atômica , Propriedades de SuperfícieRESUMO
Coronary artery and peripheral vascular diseases are the leading cause of morbidity and mortality worldwide and often require surgical intervention to replace damaged blood vessels, including the use of vascular patches in endarterectomy procedures. Tissue engineering approaches can be used to obtain biocompatible and biodegradable materials directed to this application. In this work, dense or porous scaffolds constituted of chitosan (Ch) complexed with alginate (A) or pectin (P) were fabricated and characterized considering their application as tissue-engineered vascular patches. Scaffolds fabricated with alginate presented higher culture medium uptake capacity (up to 17â¯g/g) than materials produced with pectin. A degradation study of the patches in the presence of lysozyme showed longer-term stability for Ch-P-based scaffolds. Pectin-containing matrices presented higher elastic modulus (around 280â¯kPa) and ability to withstand larger deformations. Moreover, these materials demonstrated better performance when tested for hemocompatibility, with lower levels of platelet adhesion and activation. Human smooth muscle cells (HSMC) adhered, spread and proliferated better on matrices produced with pectin, probably as a consequence of cell response to higher stiffness of this material. Thus, the outcomes of this study demonstrate that Ch-P-based scaffolds present superior characteristics for the application as vascular patches. Despite polysaccharides are yet underrated in this field, this work shows that biocompatible tridimensional structures based on these polymers present high potential to be applied for the reconstruction and regeneration of vascular tissues.
Assuntos
Polissacarídeos/química , Engenharia Tecidual/métodos , Doenças Vasculares/terapia , Alginatos/química , Materiais Biocompatíveis/química , Células Cultivadas , Quitosana/química , Humanos , Miócitos de Músculo Liso/efeitos dos fármacos , Pectinas/química , Polímeros/química , Alicerces Teciduais/químicaRESUMO
The aim of this work was to evaluate the cellular response to titanium nanotube arrays with variable crystalline structure. Cytotoxicity, viability and the ability of the titania nanotube arrays to stimulate adhesion and proliferation of adipose derived stem cells (ADSCs) was evaluated. Titania nanotube arrays were fabricated by electrochemical anodization of titanium in diethyleneglycol/hydrofluoric acid electrolyte at 60â¯V for 6â¯h, then annealed at 300, 530 and 630⯰C for 5â¯h. The nanotube arrays were characterized using scanning electron microscopy (SEM), contact angle goniometry, x-ray diffraction (XRD) and protein adsorption. ADSCs were cultured on titania nanotube arrays at a density of 1â¯×â¯104 cells/ml. The cells were allowed to adhere and to proliferate for 1, 4 and 7â¯days. Cell viability was characterized by the CellTiter-Blue® Cell Viability Assay; and cell morphology was characterized by SEM. Cell adhesion, proliferation and morphology were characterized using fluorescence microscopy by staining the cells with DAPI and rhodamine/phalloidin. The results from this study showed that the annealing at 300 and 530⯰C formed anatase phase, and annealing at 630⯰C formed anatase/rutile phase. The results indicated that the modification of the crystalline structure (i.e. anatase/rutile phase) of titania nanotube arrays influenced the ADSC adhesion and proliferation. Future studies are now directed towards evaluating differentiation of this cellular model in osteoblasts.
Assuntos
Tecido Adiposo/metabolismo , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Nanotubos/química , Células-Tronco/metabolismo , Titânio , Tecido Adiposo/citologia , Sobrevivência Celular/efeitos dos fármacos , Humanos , Células-Tronco/citologia , Titânio/química , Titânio/farmacologiaRESUMO
Collagen-based materials are probably among the most used class of biomaterials in tissue engineering and regenerative medicine. Although collagen is often privileged for providing a suitable substrate on which cells can be cultured or a matrix in which cells can be dispersed, its mechanical properties represent a major limitation for clinical translation and even for handling of the obtained regenerated tissue. In this work, the combination of polysaccharides chitosan (Ch) and xanthan gum (X) was investigated as an alternative for scaffolds for soft tissue engineering. Moreover, in an attempt to reach a compromise between obtaining highly porous biomaterials while maintaining appropriate mechanical properties, a surfactant (Kolliphor® P188, K) was added to Ch-X matrices to generate pores, while silicone rubber (Silpuran® 2130A/B, S) was used to balance their mechanical properties. Addition of K (10 or 25% w/w) increased the porosity and pore-dimensions, while addition of S improved by up to 156% and 85% the elastic moduli and the elastic behavior of Ch-X-based scaffolds, under both compressive and tensile loads, respectively, at 50% strain. Relaxation tests confirmed that these materials do have a viscoelastic behavior. The presence of S increased thickness and microscale surface roughness and did not affect liquid uptake and stability, thrombogenicity, biodegradation and cytotoxicity of polysaccharide-based scaffolds. In conclusion, this work shows that Ch-X-S porous blends constitute suitable scaffolds for soft tissue engineering.
Assuntos
Fenômenos Mecânicos , Polissacarídeos/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Morte Celular , Quitosana/química , Módulo de Elasticidade , Fibroblastos/citologia , Humanos , Muramidase/metabolismo , Polissacarídeos Bacterianos/química , Porosidade , Estresse Mecânico , Trombose/patologia , Água/químicaRESUMO
In this study, we investigate the formation of calcium and phosphorus-doped TiO2 nanotubes, produced by potentiostatic anodization of Ti in viscous electrolyte-containing HF and Ca/P ions. Characterization of the produced oxide layer was conducted using scanning electron microscopy, glancing-angle X-ray diffraction, X-ray photoelectron spectroscopy, contact angle, and protein adsorption measurements. Adipose-derived stem cells were used to study material cytotoxicity, cell viability and proliferation, and cell morphology and growth. To evaluate the adipose-derived stem-cell differentiation, we investigated the expression of osteocalcin and osteopontin by cells as well as calcium mineralization. Results show that it was possible to produce a superhydrophilic titanium oxide nanotube layer with incorporation of Ca and P ions. The presence of Ca and P in the oxide layer not only improved the cell adhesion and proliferation but also stimulated the production of key marker proteins indicating differentiation of cells.