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1.
Int J Biol Macromol ; 143: 126-135, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31805330

RESUMO

Snail mucus is an attractive natural substance, which is increasingly used in cosmetic creams and syrups thanks to its emollient, moisturizing, protective and reparative properties. The aim of the present study was to explore the physicochemical properties of chitosan-based films added with snail mucus extracted from Helix Aspersa Muller. To this aim, chitosan films at different content of snail mucus were fabricated by simple solvent casting technique. The results of X-ray diffraction analyses, tensile mechanical tests, Infrared spectroscopy and thermogravimetry demonstrated that snail mucus addition strongly modifies the properties of chitosan films. In particular, it acted like a plasticizer enhancing films extensibility up to ten times and strongly improving their water barrier and bioadhesion properties, with a trend depending on Snail mucus content. Furthermore, it provides the films with antibacterial properties and enhanced cytocompatibility, yielding materials with tailored properties for specific requirements.

2.
Materials (Basel) ; 12(17)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31480538

RESUMO

The majority of the crosslinking approaches employed to confer water resistance properties to electrospun gelatin mats are based on the use of potential cytotoxic agents, turning out to be not suitable for biomedical applications. Environmentally friendly chemical strategies based on the use of non-toxic agents are, therefore, strongly demanded. In the present work, the possibility to produce crosslinked electrospun fish gelatin mats by electrospinning an aqueous solution, containing citric acid as a crosslinking agent, is reported. The effect of pH on solution rheological properties, as well as on the electrospun mat morphology, chemistry, and crosslinking degree, is assessed. The increase of solution pH from 1.8 to 3.7 allows for obtaining fibers that maintain the fibrous morphology also in the mat. Subsequent thermal treatment of the electrospun mat (80 °C for 30 min) turns out to increase the crosslinking degree and morphological stability of the mat.

3.
Molecules ; 24(10)2019 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-31109143

RESUMO

3D cylindrical layered scaffolds with anisotropic mechanical properties were prepared according to a new and simple method, which involves gelatin foaming, deposition of foamed strips, in situ crosslinking, strip rolling and lyophilization. Different genipin concentrations were tested in order to obtain strips with different crosslinking degrees and a tunable stability in biological environment. Before lyophilization, the strips were curled in a concentric structure to generate anisotropic spiral-cylindrical scaffolds. The scaffolds displayed significantly higher values of stress at break and of the Young modulus in compression along the longitudinal than the transverse direction. Further improvement of the mechanical properties was achieved by adding strontium-substituted hydroxyapatite (Sr-HA) to the scaffold composition and by increasing genipin concentration. Moreover, composition modulated also water uptake ability and degradation behavior. The scaffolds showed a sustained strontium release, suggesting possible applications for the local treatment of abnormally high bone resorption. This study demonstrates that assembly of layers of different composition can be used as a tool to obtain scaffolds with modulated properties, which can be loaded with drugs or biologically active molecules providing properties tailored upon the needs.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Módulo de Elasticidade , Hidroxiapatitas/química , Estrôncio/administração & dosagem , Tecidos Suporte/química , Anisotropia , Osso e Ossos/cirurgia , Reagentes para Ligações Cruzadas/química , Liberação Controlada de Fármacos , Gelatina/química , Cinética , Estrôncio/química , Engenharia Tecidual/métodos
4.
Int J Pharm ; 554: 245-255, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30423416

RESUMO

In this study, we loaded a biomimetic calcium phosphate bone cement (CPC) with relatively high amounts of a bisphosphonate through the use of Solid Lipid Microparticles (MPs) and investigated bone cells response to the composite cements. 10, 20 and 30% w/w of Alendronate (AL) were successfully introduced into microparticles of Cutina HR and Precirol, which were prepared by means of spray-congealing technique. Addition of AL-loaded MPs to the cement composition provoked a lengthening of the setting and of the hardening processes. However, setting times were still in a range useful for clinical applications, except for the cements at the highest Alendronate content. The composite cements displayed a sustained drug release over time. Cements with the best performances in terms of setting, hardening, mechanical properties and drug release were submitted to in vitro tests using a co-culture model of osteoblast and osteoclast. The results showed that the use of MPs to enrich the cement composition with Alendronate provides materials able to inhibit osteoclast viability and activity, while promoting osteoblast viability and earlier differentiation, indicating that the MPs-cements are good delivery systems for bisphosphonates.


Assuntos
Alendronato/administração & dosagem , Cimentos para Ossos/química , Conservadores da Densidade Óssea/administração & dosagem , Fosfatos de Cálcio/química , Alendronato/química , Alendronato/farmacologia , Materiais Biomiméticos/química , Conservadores da Densidade Óssea/química , Conservadores da Densidade Óssea/farmacologia , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Química Farmacêutica/métodos , Técnicas de Cocultura , Preparações de Ação Retardada , Liberação Controlada de Fármacos , Humanos , Lipídeos , Microesferas , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos
5.
Macromol Biosci ; 18(7): e1800096, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29877029

RESUMO

Strontium has a beneficial role on bone remodeling and is proposed for the treatment of pathologies associated to excessive bone resorption, such as osteoporosis. Herein, the possibility to utilize a biomimetic scaffold as strontium delivery system is explored. Porous 3D gelatin scaffolds containing about 30% of strontium substituted hydroxyapatite (SrHA) or pure hydroxyapatite (HA) are prepared by freeze-drying. The scaffolds display a very high open porosity, with an interconnectivity of 100%. Reinforcement with further amount of gelatin provokes a modest decrease of the average pore size, without reducing interconnectivity. Moreover, reinforced scaffolds display reduced water uptake ability and increased values of mechanical parameters when compared to as-prepared scaffolds. Strontium displays a sustained release in phosphate buffered saline: the quantities released after 14 d from as-prepared and reinforced scaffolds are just 14 and 18% of the initial content, respectively. Coculture of osteoblasts and osteoclasts shows that SrHA-containing scaffolds promote osteoblast viability and activity when compared to HA-containing scaffolds. On the other hand, osteoclastogenesis and osteoclast differentiation are significantly inhibited on SrHA-containing scaffolds, suggesting that these systems could be usefully applied for local delivery of strontium in loci characterized by excessive bone resorption.


Assuntos
Materiais Biomiméticos/síntese química , Preparações de Ação Retardada/síntese química , Gelatina/química , Hidroxiapatitas/química , Osteoblastos/efeitos dos fármacos , Estrôncio/farmacologia , Reabsorção Óssea/prevenção & controle , Diferenciação Celular/efeitos dos fármacos , Técnicas de Cocultura , Liberação Controlada de Fármacos , Humanos , Cinética , Modelos Biológicos , Osteoblastos/citologia , Osteoblastos/fisiologia , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos , Osteoclastos/fisiologia , Porosidade , Estrôncio/química , Estrôncio/metabolismo , Engenharia Tecidual , Tecidos Suporte
6.
Colloids Surf B Biointerfaces ; 163: 73-82, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29278802

RESUMO

In this paper we developed an innovative, effective and rapid one-step approach to crosslink mucoadhesive gelatin films for buccal drug delivery. The method, which involves the application of non-equilibrium pressure plasma for 3 or 5 minutes/side, was compared with a classical approach based on the use of a chemical crosslinking agent, namely genipin. Econazole nitrate (ECN), an imidazole antifungal agent used for the treatment of skin infections and mucosal candidiasis, was selected as model drug. X-Ray Diffraction characterization performed on the drug-containing gelatin films revealed that ECN undergoes to a topotactic transformation into Econazole (EC) immediately after mixing with gelatin suggesting the occurrence of an acid-base reaction between drug and gelatin during film processing. Plasma treatment, as well as genipin crosslinking, did not provoke any further variation of EC structure. However, plasma exposure significantly improved films adhesiveness and allowed to reach mucoadhesive strength values more than double with respect to those obtained with genipin, ascribable to the presence of polar and hydrophilic groups on the plasma treated film's surface. A residence time of at least 48 h was obtained by properly selecting the plasma exposure times. These results, together with the in-vitro data showing retention of antifungal efficacy against a strain of Candida albicans, demonstrated that plasma treatment was a valid and rapid alternative, easy to scale-up, to chemical crosslinking methods for the production of highly mucoadhesive gelatin-based films.


Assuntos
Reagentes para Ligações Cruzadas/química , Portadores de Fármacos , Gelatina/química , Iridoides/química , Gases em Plasma/química , Adesividade , Administração Bucal , Animais , Antifúngicos/química , Antifúngicos/farmacologia , Pressão Atmosférica , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Econazol/química , Econazol/farmacologia , Cinética , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/metabolismo , Suínos , Resistência à Tração
7.
J Biomed Mater Res A ; 106(4): 914-923, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29143449

RESUMO

The demand of new strategies for the induction of bone regeneration is continuously increasing. Biomimetic porous gelatin-nanocrystalline hydroxyapatite scaffolds with tailored properties were previously developed, showing a positive response in terms of cell adhesion, proliferation, and differentiation. In the present paper, we focused on their osteoinductive properties. The effect of scaffolds on osteogenic differentiation of human mesenchymal stromal cells (hMSCs) was investigated in vitro. hMSCs were seeded on GEL (type A gelatin) and GEL containing 10 wt% hydroxyapatite (GEL-HA) and cultured in osteogenic medium. Results showed that GEL and GEL-HA10 sustained hMSC differentiation, with an increased ALP activity and a higher expression of bone specific genes. The osteoinductive ability of these scaffolds was then studied in vivo in a heterotopic bone formation model in nude mice. The influence of hMSCs within the implants was examined as well. Both GEL and GEL-HA10 scaffolds mineralized when implanted without hMSCs. On the contrary, the presence of hMSC abolished or reduced mineralization of GEL and GEL-HA10 scaffolds. However, we could observe a species-specific response to the presence of HA, which stimulated osteogenic differentiation of human cells only. In conclusion, the scaffolds showed promising osteoinductive properties and may be suitable for use in confined critical defects. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 914-923, 2018.


Assuntos
Durapatita/farmacologia , Gelatina/farmacologia , Células-Tronco Mesenquimais/citologia , Nanoestruturas/química , Osseointegração , Animais , Biomarcadores/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Coristoma/patologia , Reagentes para Ligações Cruzadas/química , Gelatina/ultraestrutura , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Iridoides/química , Masculino , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos Nus , Nanoestruturas/ultraestrutura , Osseointegração/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Osteogênese/genética , Microtomografia por Raio-X
8.
Eur J Pharm Biopharm ; 122: 6-16, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28986297

RESUMO

The aim of this work was to develop an innovative drug delivery system potentially useful for the local delivery of Bisphosphonates to bone tissue. We propose the use of Solid Lipid Microparticles (MPs), up to now mainly used for oral and topical drug delivery, as carrier for bisphosphonates due to the favourable biocompatibility and lower toxicity of the lipids compared with many polymers. The delivery platform consisted of a biomimetic α-tricalcium phosphate-gelatin cement (CPC) enriched with alendronate loaded MPs (MPs-AL) produced by the spray congealing technology. Alendronate direct addition to cement composition is limited since Alendronate is able to sequester calcium from calcium phosphates, thus preventing the setting of the cements. At variance, this approach permitted to load a relatively high amount of the drug on the CPC and allowed the controlled release of the highly water soluble alendronate. A Design of Experiment (DoE) was employed for the screening of the effects of the formulation variables related to the presence of unloaded microparticle (MPs) on the cement most important mechanical properties. Then, MPs loaded with 10% w/w of alendronate were produced using five different carriers (Stearic Acid, Stearilic Alcohol, Cutina HR, Tristearin and Precirol ATO5). All MPs-AL exhibited a spherical shape, encapsulation efficiency higher than 90% and prevalent particle size ranging from 100 to 150µm. Solid state characterization (DSC, HSM and X-ray powder diffraction) demonstrated that encapsulation of alendronate into MPs did not alter its crystal structure. MPs-AL addition to the cement provoked a modest lengthening of the setting times and of the hardening reaction leading to the complete transformation of α-tricalcium phosphate into calcium-deficient hydroxyapatite, without significantly affect the cement mechanical properties. Moreover, the results of in vitro AL release study performed on cements enriched with MPs-AL showed that the system allows a controlled release of the drug over time.


Assuntos
Cimentos para Ossos/química , Fosfatos de Cálcio/química , Difosfonatos/química , Lipídeos/química , Alendronato/química , Materiais Biocompatíveis/química , Química Farmacêutica/métodos , Preparações de Ação Retardada , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura/métodos , Tamanho da Partícula , Polímeros/química , Difração de Raios X/métodos
9.
Macromol Biosci ; 17(3)2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27748576

RESUMO

The systemic administration of bisphosphonates (BPs) for the treatment of metabolic diseases characterized by abnormal bone loss suffers from several adverse side effects, which can be reduced by implementation of alternative modes of administration. In this work, glutaraldehyde cross-linked gelatin scaffolds are proposed as delivery systems of calcium alendronate monohydrate (CaAL•H2 O). The 3D highly porous scaffolds display a relevant interconnected porosity (>94%), independently from CaAL•H2 O content (0, 3, and 6 wt%). At variance, pore size varies with composition. The relative increase of the number of smaller pores on increasing BP content is in agreement with the parallel significant increase of the compressive modulus and collapse strength. The scaffolds exhibit a sustained CaAL•H2 O release profile, and a significant amount of the drug is retained in the scaffolds even after 14 d. In vitro tests are carried out using cocultures of osteoblast (OB) and osteoclast (OC). The evaluation of differentiation markers is performed both on the supernatants of cell culture and by means of quantitative polymerase chain reaction. The results indicate that BP containing scaffolds support osteoblast proliferation and differentiation, whereas they inhibit osteoclast viability and activity, displaying a promising beneficial role on bone repair processes.


Assuntos
Alginatos/administração & dosagem , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Alginatos/química , Gelatina/administração & dosagem , Gelatina/química , Ácido Glucurônico/administração & dosagem , Ácido Glucurônico/química , Glutaral/administração & dosagem , Glutaral/química , Ácidos Hexurônicos/administração & dosagem , Ácidos Hexurônicos/química , Humanos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Porosidade , Tecidos Suporte/química
10.
Sci Rep ; 6: 38542, 2016 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-27924840

RESUMO

Electrospun gelatin nanofibers attract great interest as a natural biomaterial for cartilage and tendon repair despite their high solubility in aqueous solution, which makes them also difficult to crosslink by means of chemical agents. In this work, we explore the efficiency of non-equilibrium atmospheric pressure plasma in stabilizing gelatin nanofibers. We demonstrate that plasma represents an innovative, easy and environmentally friendly approach to successfully crosslink gelatin electrospun mats directly in the solid state. Plasma treated gelatin mats display increased structural stability and excellent retention of fibrous morphology after immersion in aqueous solution. This method can be successfully applied to induce crosslinking both in pure gelatin and genipin-containing gelatin electrospun nanofibers, the latter requiring an even shorter plasma exposure time. A complete characterization of the crosslinked nanofibres, including mechanical properties, morphological observations, stability in physiological solution and structural modifications, has been carried out in order to get insights on the occurring reactions triggered by plasma.

11.
Biomed Mater ; 11(2): 025007, 2016 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-26987305

RESUMO

Crosslinking of gelatin nanofibers maintaining a fibrous morphology after exposure to an aqueous solution is still a challenge. In this work, we developed an innovative method based on the use of an ad hoc designed co-axial needle to fabricate gelatin mats crosslinked with a very small amount of genipin and still able to retain their morphology when immersed in aqueous solution. Genipin-containing gelatin nanofibers are obtained by allowing mixing of the two solutions just within the needle. Genipin content of the electrospun mats can be modulated by varying feeding rates of the inner and outer solutions and their relative concentration. A subsequent thermal treatment of the mats, performed at 55 °C or 37 °C for 1 or 3 days and followed by rapid rinsing in ethanol and then in PB, allows one to obtain highly crosslinked gelatin nanofibers that perfectly maintain their morphology after immersion in an aqueous solution, display improved mechanical properties and enhanced stability. This new approach allows us to achieve gelatin mat stabilization using a very small amount of genipin with respect to other methods and to avoid post-treatment of the mats with the crosslinking agent, with a consequent significant reduction of the final cost of the materials. Moreover, in vitro tests demonstrate that the crosslinked mats support normal human primary chondrocyte culture, promoting their differentiation.


Assuntos
Gelatina/química , Nanofibras/química , Tecidos Suporte/química , Materiais Biocompatíveis/química , Diferenciação Celular , Sobrevivência Celular , Células Cultivadas , Condrócitos/citologia , Condrócitos/enzimologia , Reagentes para Ligações Cruzadas , Humanos , Iridoides , L-Lactato Desidrogenase/metabolismo , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanofibras/ultraestrutura , Nanotecnologia , Engenharia Tecidual/métodos
12.
Macromol Biosci ; 15(11): 1535-45, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26126665

RESUMO

A promising strategy for osteochondral interface regeneration consists in the development of hybrid scaffolds, composed of distinct but integrated layers able to mimic the different regions of cartilage and bone. We developed multi-layered scaffolds by assembling a gelatin layer with layers containing different amounts of gelatin and hydroxyapatite nanocrystals, and using a gelatin solution (as a glue) to stick layers together. The scaffolds exhibit a high, interconnected porosity and mechanical properties varying with composition along the thickness of the scaffolds up to values of compressive stress and modulus of about 1 and 14 MPa, respectively. In vitro tests demonstrate that the different layers of the scaffolds promote chondrogenic and osteogenic differentiation of Human Mesenchimal Stem Cells (hMSC).


Assuntos
Cartilagem/metabolismo , Durapatita/química , Células-Tronco Mesenquimais/metabolismo , Nanopartículas/química , Osteogênese , Tecidos Suporte/química , Cartilagem/citologia , Técnicas de Cocultura , Humanos , Células-Tronco Mesenquimais/citologia , Engenharia Tecidual/métodos
13.
Macromol Biosci ; 15(7): 941-52, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25787871

RESUMO

3D highly porous (93% total porosity) gelatin scaffolds were prepared according to a novel, simple method, which implies gelatin foaming, gelification, soaking into ethanol and successive freeze-drying. Reinforcement of the as-prepared scaffolds (GEL) was performed through immersion in aqueous solutions at different gelatin concentrations. Reinforcement solutions with and without genipin addition allowed to prepare two series of samples:cross-linked and uncross-linked samples, respectively. The amount of gelatin adsorbed onto the reinforced samples increases as a function of gelatin concentration in solution and provokes a drastic improvement of the compressive modulus and collapse strength up to values of about 30 and 4 MPa, respectively. The open and interconnected porosity, although slightly reduced, is still of the order of 80% in the samples reinforced with the highest concentration of gelatin. Water uptake ability evaluated after immersion in PBS for 20 s decreases with gelatin reinforcement. The presence of genipin in cross-linked samples reduces gelatin release and stabilizes the scaffolds in solution. Chondrocytes from human articular cartilage adhere, proliferate, and penetrate into the scaffolds. The evaluation of differentiation markers both on the supernatants of cell culture and by means of quantitative polymerase chain reaction (qPCR) indicates a dose-dependent promotion of cell differentiation.


Assuntos
Cartilagem Articular/fisiologia , Gelatina , Iridoides , Regeneração , Tecidos Suporte/química , Humanos , Porosidade
14.
J Pharm Biomed Anal ; 106: 92-9, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25698553

RESUMO

Due to the increased use of silver nanoparticles in industrial scale manufacturing, consumer products and nanomedicine reliable measurements of properties such as the size, shape and distribution of these nano particles in aqueous medium is critical. These properties indeed affect both functional properties and biological impacts especially in quantifying associated risks and identifying suitable risk-mediation strategies. The feasibility of on-line coupling of a fractionation technique such as hollow-fiber flow field flow fractionation (HF5) with a light scattering technique such as MALS (multi-angle light scattering) is investigated here for this purpose. Data obtained from such a fractionation technique and its combination thereof with MALS have been compared with those from more conventional but often complementary techniques e.g. transmission electron microscopy, dynamic light scattering, atomic absorption spectroscopy, and X-ray fluorescence. The combination of fractionation and multi angle light scattering techniques have been found to offer an ideal, hyphenated methodology for a simultaneous size-separation and characterization of silver nanoparticles. The hydrodynamic radii determined by fractionation techniques can be conveniently correlated to the mean average diameters determined by multi angle light scattering and reliable information on particle morphology in aqueous dispersion has been obtained. The ability to separate silver (Ag(+)) ions from silver nanoparticles (AgNPs) via membrane filtration during size analysis is an added advantage in obtaining quantitative insights to its risk potential. Most importantly, the methodology developed in this article can potentially be extended to similar characterization of metal-based nanoparticles when studying their functional effectiveness and hazard potential.


Assuntos
Nanopartículas Metálicas/química , Espalhamento de Radiação , Prata/química , Fracionamento Químico/métodos , Estudos de Viabilidade , Filtração/métodos , Luz , Tamanho da Partícula , Medição de Risco/métodos , Água/química
15.
J Mater Sci Mater Med ; 26(2): 69, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25631265

RESUMO

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.


Assuntos
Reagentes para Ligações Cruzadas/química , Gelatina/química , Glutaral/química , Iridoides/química , Membranas Artificiais , Esterilização/métodos , Reagentes para Ligações Cruzadas/efeitos da radiação , Módulo de Elasticidade/efeitos da radiação , Raios gama , Gelatina/efeitos da radiação , Glutaral/efeitos da radiação , Iridoides/efeitos da radiação , Teste de Materiais , Doses de Radiação , Estresse Mecânico , Resistência à Tração/efeitos da radiação
16.
Mater Sci Eng C Mater Biol Appl ; 36: 130-8, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24433895

RESUMO

Bio-synthetic scaffolds of interspersed poly(l-lactic acid) (PLLA) and gelatin (GEL) fibers are fabricated by co-electrospinning. Tailored PLLA/GEL compositions are obtained and GEL crosslinking with genipin provides for the maintenance of good fiber morphology. Scaffold tensile mechanical properties are intermediate between those of pure PLLA and GEL and vary as a function of PLLA content. Primary human chondrocytes grown on the scaffolds exhibit good proliferation and increased values of the differentiation parameters, especially for intermediate PLLA/GEL compositions. Mineralization tests enable the deposition of a uniform layer of poorly crystalline apatite onto the scaffolds, suggesting potential applications involving cartilage as well as cartilage-bone interface tissue engineering.


Assuntos
Condrócitos/citologia , Gelatina/farmacologia , Ácido Láctico/farmacologia , Fenômenos Mecânicos/efeitos dos fármacos , Polímeros/farmacologia , Engenharia Tecidual/métodos , Tecidos Suporte/química , Animais , Calcificação Fisiológica/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Condrócitos/efeitos dos fármacos , Condrócitos/enzimologia , Condrócitos/ultraestrutura , Reagentes para Ligações Cruzadas/química , Humanos , L-Lactato Desidrogenase/metabolismo , Poliésteres , Espectroscopia de Infravermelho com Transformada de Fourier , Sus scrofa , Resistência à Tração/efeitos dos fármacos
17.
J Biomed Mater Res A ; 101(12): 3560-70, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23629945

RESUMO

Bone cell response to 3D bioinspired scaffolds was tested on osteoblast culture supernatants and by means of quantitative polymerase chain reaction (qPCR). Foaming and freeze-drying method was optimized in order to obtain three-dimensional interconnected porous scaffolds of gelatin at different contents of nanocrystalline hydroxyapatite (HA). Addition of a non toxic crosslinking agent during foaming stabilized the scaffolds, as confirmed by the slow and relatively low gelatin release in phosphate buffer up to 28 days. Micro-computed tomography reconstructed images showed porous interconnected structures, with interconnected pores displaying average diameter ranging from about 158 to about 71 µm as the inorganic phase content increases from 0 to 50 wt %. The high values of connectivity (>99%), porosity (> 60%), and percentage of pores with a size in the range 100-300 µm (>50%) were maintained up to 30 wt % HA, whereas higher content provoked a reduction of these parameters, as well as of the average pore size, and a significant increase of the compressive modulus and collapse strength up to 8 ± 1 and 0.9 ± 0.2 MPa, respectively. Osteoblast cultured on the scaffolds showed good adhesion, proliferation and differentiation. The presence of HA promoted ALP activity, TGF-ß1, and osteocalcin production, in agreement with the observed upregulation of ALP, OC, Runx2, and TGF-ß1 gene in qPCR analysis, indicating that the composite scaffolds enhanced osteoblast activation and extra-cellular matrix mineralization processes.


Assuntos
Materiais Biomiméticos/farmacologia , Osteoblastos/citologia , Tecidos Suporte/química , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Durapatita/química , Módulo de Elasticidade/efeitos dos fármacos , Humanos , Microscopia Eletrônica de Varredura , Nanopartículas/ultraestrutura , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoblastos/ultraestrutura , Reação em Cadeia da Polimerase , Porosidade/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espectrometria por Raios X , Estresse Mecânico , Sus scrofa , Termogravimetria , Microtomografia por Raio-X
18.
J Inorg Biochem ; 105(8): 1060-5, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21726768

RESUMO

We previously proposed a biomimetic α-tricalcium phosphate (α-TCP) bone cement where gelatin controls the transformation of α-TCP into calcium deficient hydroxyapatite (CDHA), leading to improved mechanical properties. In this study we investigated the setting and hardening processes of biomimetic cements containing increasing amounts of CaHPO(4)·2H2O (DCPD) (0, 2.5, 5, 10, 15 wt.%), with the aim to optimize composition. Both initial and final setting times increased significantly when DCPD content accounts for 10 wt.%, whereas cements containing 15 wt.% DCPD did not set at all. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry (TG) and scanning electron microscopy (SEM) investigations were performed on samples maintained in physiological solution for different times. DCPD dissolution starts soon after cement preparation, but the rate of transformation decreases on increasing DCPD initial content in the samples. The rate of α-TCP to CDHA conversion during hardening decreases on increasing DCPD initial content. Moreover, the presence of DCPD prevents gelatin release during hardening. The combined effects of gelatin and DCPD on the rate of CDHA formation and porosity lead to significantly improved mechanical properties, with the best composition displaying a compressive strength of 35 MPa and a Young modulus of 1600 MPa.


Assuntos
Materiais Biomiméticos/química , Cimentos para Ossos/química , Fosfatos de Cálcio/química , Fosfatos de Cálcio/metabolismo , Força Compressiva , Teste de Materiais , Microscopia Eletrônica de Varredura , Difração de Raios X
19.
Acta Biomater ; 7(4): 1702-9, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21095244

RESUMO

The development of suitable biomimetic three-dimensional scaffolds is a fundamental requirement of tissue engineering. This paper presents the first successful attempt to obtain electrospun gelatin nanofibers cross-linked with a low toxicity agent, genipin, and able to retain the original nanofiber morphology after water exposure. The optimized procedure involves an electrospinning solution containing 30 wt.% gelatin in 60/40 acetic acid/water (v/v) and a small amount of genipin, followed by further cross-linking of the as-electrospun mats in 5% genipin solution for 7 days, rinsing in phosphate-buffered saline and then air drying at 37°C. The results of scanning electron microscopy investigations indicated that the cross-linked nanofibers were defect free and very regular and they also maintained the original morphology after exposure to water. Genipin addition to the electrospinning solution dramatically reduced the extensibility of the as-electrospun mats, which displayed further remarkable improvements in elastic modulus and stress at break after successive cross-linking up to values of about 990 and 21 MPa, respectively. The results of the preliminary in vitro tests carried out using vascular wall mesenchymal stem cells indicated good cell viability and adhesion to the gelatin scaffolds.


Assuntos
Reagentes para Ligações Cruzadas/farmacologia , Gelatina/química , Glicosídeos Iridoides/farmacologia , Nanofibras/química , Engenharia Tecidual/métodos , Água/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Humanos , Iridoides , Teste de Materiais , Fenômenos Mecânicos/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/ultraestrutura , Nanofibras/ultraestrutura , Tamanho da Partícula , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Sus scrofa , Difração de Raios X
20.
Biomaterials ; 26(19): 4085-9, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15664635

RESUMO

We obtained a fast biomimetic deposition of hydroxyapatite (HA) coatings on Ti6Al4V substrates using a slightly supersaturated Ca/P solution, with an ionic composition simpler than that of simulated body fluid (SBF). At variance with other fast deposition methods, which produce amorphous calcium phosphate coatings, the new proposed composition allows one to obtain nanocrystalline HA. Soaking in supersaturated Ca/P solution results in the deposition of a uniform coating in a few hours, whereas SBF, or even 1.5SBF, requires 14 days to deposit a homogeneous coating on the same substrates. The coating consists of HA globular aggregates, which exhibit a finer lamellar structure than those deposited from SBF. The extent of deposition increases on increasing the immersion time. Transmission electron microscope (TEM) images recorded on the material detached from the coating show that the deposition is constituted of thin nanocrystals. Electron diffraction (ED) patterns recorded from most of the crystals exhibit the presence of rings, which can be indexed as reflections characteristic of HA. Furthermore, several HA single-crystal spot ED images were obtained from individual crystals.


Assuntos
Biomimética/métodos , Líquidos Corporais/química , Materiais Revestidos Biocompatíveis/química , Cristalização/métodos , Durapatita/química , Nanoestruturas/análise , Nanoestruturas/química , Titânio/química , Fosfatos de Cálcio , Materiais Revestidos Biocompatíveis/análise , Durapatita/análise , Teste de Materiais , Propriedades de Superfície , Titânio/análise
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