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1.
Acta Biomater ; 176: 156-172, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38281674

RESUMO

The combination of hydrogels and magnetic nanoparticles, scarcely explored to date, offers a wide range of possibilities for innovative therapies. Herein, we have designed hybrid 3D matrices integrating natural polymers, such as collagen, chitosan (CHI) and hyaluronic acid (HA), to provide soft and flexible 3D networks mimicking the extracellular matrix of natural tissues, and iron oxide nanoparticles (IONPs) that deliver localized heat when exposed to an alternating magnetic field (AMF). First, colloidally stable nanoparticles with a hydrodynamic radius of ∼20 nm were synthesized and coated with either CHI (NPCHI) or HA (NPHA). Then, collagen hydrogels were homogeneously loaded with these coated-IONPs resulting in soft (E0 ∼ 2.6 kPa), biodegradable and magnetically responsive matrices. Polymer-coated IONPs in suspension preserved primary neural cell viability and neural differentiation even at the highest dose (0.1 mg Fe/mL), regardless of the coating, even boosting neuronal interconnectivity at lower doses. Magnetic hydrogels maintained high neural cell viability and sustained the formation of highly interconnected and differentiated neuronal networks. Interestingly, those hydrogels loaded with the highest dose of NPHA (0.25 mgFe/mg polymer) significantly impaired non-neuronal differentiation with respect to those with NPCHI. When evaluated under AMF, cell viability slightly diminished in comparison with control hydrogels magnetically stimulated, but not compared to their counterparts without stimulation. Neuronal differentiation under AMF was only affected on collagen hydrogels with the highest dose of NPHA, while non-neuronal differentiation regained control values. Taken together, NPCHI-loaded hydrogels displayed a superior performance, maybe benefited from their higher nanomechanical fluidity. STATEMENT OF SIGNIFICANCE: Hydrogels and magnetic nanoparticles are undoubtedly useful biomaterials for biomedical applications. Nonetheless, the combination of both has been scarcely explored to date. In this study, we have designed hybrid 3D matrices integrating both components as promising magnetically responsive platforms for neural therapeutics. The resulting collagen scaffolds were soft (E0 ∼ 2.6 kPa) and biodegradable hydrogels with capacity to respond to external magnetic stimuli. Primary neural cells proved to grow on these substrates, preserving high viability and neuronal differentiation percentages even under the application of a high-frequency alternating magnetic field. Importantly, those hydrogels loaded with chitosan-coated iron oxide nanoparticles displayed a superior performance, likely related to their higher nanomechanical fluidity.


Assuntos
Quitosana , Hidrogéis , Hidrogéis/farmacologia , Quitosana/farmacologia , Colágeno/farmacologia , Ácido Hialurônico/farmacologia , Técnicas de Cultura de Células , Fenômenos Magnéticos
2.
Small ; 20(6): e2304884, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37775942

RESUMO

The nanomechanical response of a cell depends on the frequency at which the cell is probed. The components of the cell that contribute to this property and their interplay are not well understood. Here, two force microscopy methods are integrated to characterize the frequency and/or the velocity-dependent properties of living cells. It is shown on HeLa and fibroblasts, that cells soften and fluidize upon increasing the frequency or the velocity of the deformation. This property was independent of the type and values (25 or 1000 nm) of the deformation. At low frequencies (2-10 Hz) or velocities (1-10 µm s-1 ), the response is dominated by the mechanical properties of the cell surface. At higher frequencies (>10 Hz) or velocities (>10 µm s-1 ), the response is dominated by the hydrodynamic drag of the cytosol. Softening and fluidization does not seem to involve any structural remodeling. It reflects a redistribution of the applied stress between the solid and liquid-like elements of the cell as the frequency or the velocity is changed. The data indicates that the quasistatic mechanical properties of a cell featuring a cytoskeleton pathology might be mimicked by the response of a non-pathological cell which is probed at a high frequency.


Assuntos
Mamíferos , Fenômenos Mecânicos , Humanos , Animais , Módulo de Elasticidade , Microscopia de Força Atômica , Células HeLa , Membrana Celular
3.
Nanoscale ; 15(42): 17173-17183, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37853851

RESUMO

Graphene oxide (GO) and reduced graphene oxide (rGO) have been widely used in the field of tissue regeneration and various biomedical applications. In order to use these nanomaterials in organisms, it is imperative to possess an understanding of their impact on different cell types. Due to the potential of these nanomaterials to enter the bloodstream, interact with the endothelium and accumulate within diverse tissues, it is highly relevant to probe them when in contact with the cellular components of the vascular system. Endothelial progenitor cells (EPCs), involved in blood vessel formation, have great potential for tissue engineering and offer great advantages to study the possible angiogenic effects of biomaterials. Vascular endothelial growth factor (VEGF) induces angiogenesis and regulates vascular permeability, mainly activating VEGFR2 on endothelial cells. The effects of GO and two types of reduced GO, obtained after vacuum-assisted thermal treatment for 15 min (rGO15) and 30 min (rGO30), on porcine endothelial progenitor cells (EPCs) functionality were assessed by analyzing the nanomaterial intracellular uptake, reactive oxygen species (ROS) production and VEGFR2 expression by EPCs. The results evidence that short annealing (15 and 30 minutes) at 200 °C of GO resulted in the mitigation of both the increased ROS production and decline in VEGFR2 expression of EPCs upon GO exposure. Interestingly, after 72 hours of exposure to rGO30, VEGFR2 was higher than in the control culture, suggesting an early angiogenic potential of rGO30. The present work reveals that discrete variations in the reduction of GO may significantly affect the response of porcine endothelial progenitor cells.


Assuntos
Células Progenitoras Endoteliais , Nanoestruturas , Animais , Suínos , Células Progenitoras Endoteliais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Nanoestruturas/toxicidade
4.
ACS Nano ; 16(9): 13430-13467, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36000717

RESUMO

Along with the development of the next generation of biomedical platforms, the inclusion of graphene-based materials (GBMs) into therapeutics for spinal cord injury (SCI) has potential to nourish topmost neuroprotective and neuroregenerative strategies for enhancing neural structural and physiological recovery. In the context of SCI, contemplated as one of the most convoluted challenges of modern medicine, this review first provides an overview of its characteristics and pathophysiological features. Then, the most relevant ongoing clinical trials targeting SCI, including pharmaceutical, robotics/neuromodulation, and scaffolding approaches, are introduced and discussed in sequence with the most important insights brought by GBMs into each particular topic. The current role of these nanomaterials on restoring the spinal cord microenvironment after injury is critically contextualized, while proposing future concepts and desirable outputs for graphene-based technologies aiming to reach clinical significance for SCI.


Assuntos
Grafite , Traumatismos da Medula Espinal , Regeneração da Medula Espinal , Grafite/farmacologia , Grafite/uso terapêutico , Humanos , Preparações Farmacêuticas , Medula Espinal , Traumatismos da Medula Espinal/tratamento farmacológico
5.
Pharmaceutics ; 13(8)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34452110

RESUMO

Due to their specific mesoporous structure and large surface area, mesoporous bioactive glasses (MBGs) possess both drug-delivery ability and effective ionic release to promote bone regeneration by stimulating osteogenesis and angiogenesis. Macrophages secrete mediators that can affect both processes, depending on their phenotype. In this work, the action of ion release from MBG-75S, with a molar composition of 75SiO2-20CaO-5P2O5, on osteogenesis and angiogenesis and the modulatory role of macrophages have been assessed in vitro with MC3T3-E1 pre-osteoblasts and endothelial progenitor cells (EPCs) in monoculture and in coculture with RAW 264.7 macrophages. Ca2+, phosphorous, and silicon ions released from MBG-75S were measured in the culture medium during both differentiation processes. Alkaline phosphatase activity and matrix mineralization were quantified as the key markers of osteogenic differentiation in MC3T3-E1 cells. The expression of CD31, CD34, VEGFR2, eNOS, and vWF was evaluated to characterize the EPC differentiation into mature endothelial cells. Other cellular parameters analyzed included the cell size and complexity, intracellular calcium, and intracellular content of the reactive oxygen species. The results obtained indicate that the ions released by MBG-75S promote osteogenesis and angiogenesis in vitro, evidencing a macrophage inhibitory role in these processes and demonstrating the high potential of MBG-75S for the preparation of implants for bone regeneration.

6.
Nanomaterials (Basel) ; 11(5)2021 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-33923311

RESUMO

Angiogenic biomaterials are designed to promote vascularization and tissue regeneration. Nanoparticles of bioactive materials loaded with drugs represent an interesting strategy to stimulate osteogenesis and angiogenesis and to inhibit bone resorption. In this work, porcine endothelial progenitor cells (EPCs), essential for blood vessel formation, were isolated and characterized to evaluate the in vitro effects of unloaded (NanoMBGs) and ipriflavone-loaded nanospheres (NanoMBG-IPs), which were designed to prevent osteoporosis. The expression of vascular endothelial growth factor receptor 2 (VEGFR2) was studied in EPCs under different culture conditions: (a) treatment with NanoMBGs or NanoMBG-IPs, (b) culture with media from basal, M1, and M2 macrophages previously treated with NanoMBGs or NanoMBG-IPs, (c) coculture with macrophages in the presence of NanoMBGs or NanoMBG-IPs, and (d) coculture with M2d angiogenic macrophages. The endocytic mechanisms for nanosphere incorporation by EPCs were identified using six different endocytosis inhibitors. The results evidence the great potential of these nanomaterials to enhance VEGFR2 expression and angiogenesis, after intracellular incorporation by EPCs through clathrin-dependent endocytosis, phagocytosis, and caveolae-mediated uptake. The treatment of EPCs with basal, M1, and M2 macrophage culture media and EPC/macrophage coculture studies also confirmed the angiogenic effect of these nanospheres on EPCs, even in the presence of phagocytic cells.

7.
Heliyon ; 7(12): e08645, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35005290

RESUMO

Waste treatments, which add value to the production system, may contribute to achieving a more circular economy. These recovery treatments are material recycling, composting and digestion, and energy recovery. This paper analyses recycling activity and other waste treatments in the European Union (EU), using a comparative approach among its Member States. In order to do this, some factors that may influence these treatments are studied, such as economic development, R&D expenditure, resource productivity and the period of each country's permanence in the EU. Although waste treatment rates have converged between countries from 2010 to 2018, there are still differences. In order to explain these differences, the countries have been grouped into three clusters through a K-means non-hierarchical cluster statistical analysis. Subsequently, a non-parametric Kruskal-Wallis test has been applied to examine whether these observed differences are significant in the last year of the period analysed. The results corroborate the main hypothesis of this research: there are various behaviour patterns in waste treatments according to the country clusters and based on their real GDP per capita, R&D expenditure, resource productivity and number of years as an EU member.

8.
Spec Care Dentist ; 40 Suppl 1: 3-81, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33202040

RESUMO

BACKGROUND: Inherited epidermolysis bullosa (EB) is a genetic disorder characterized by skin fragility and unique oral features. AIMS: To provide (a) a complete review of the oral manifestations in those living with each type of inherited EB, (b) the current best practices for managing oral health care of people living with EB, (c) the current best practices on dental implant-based oral rehabilitation for patients with recessive dystrophic EB (RDEB), and (d) the current best practice for managing local anesthesia, principles of sedation, and general anesthesia for children and adults with EB undergoing dental treatment. METHODS: Systematic literature search, panel discussion including clinical experts and patient representatives from different centers around the world, external review, and guideline piloting. RESULTS: This article has been divided into five chapters: (i) general information on EB for the oral health care professional, (ii) systematic literature review on the oral manifestations of EB, (iii) oral health care and dental treatment for children and adults living with EB-clinical practice guidelines, (iv) dental implants in patients with RDEB-clinical practice guidelines, and (v) sedation and anesthesia for adults and children with EB undergoing dental treatment-clinical practice guidelines. Each chapter provides recommendations on the management of the different clinical procedures within dental practice, highlighting the importance of patient-clinician partnership, impact on quality of life, and the importance of follow-up appointments. Guidance on the use on nonadhesive wound care products and emollients to reduce friction during patient care is provided. CONCLUSIONS: Oral soft and hard tissue manifestations of inherited EB have unique patterns of involvement associated with each subtype of the condition. Understanding each subtype individually will help the professionals plan long-term treatment approaches.


Assuntos
Anestesia Dentária , Epidermólise Bolhosa Distrófica , Epidermólise Bolhosa , Adulto , Criança , Humanos , Saúde Bucal , Guias de Prática Clínica como Assunto , Qualidade de Vida
9.
Adv Biosyst ; 4(9): e2000117, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32761896

RESUMO

Understanding neural physiopathology requires advances in nanotechnology-based interfaces, engineered to monitor the functional state of mammalian nervous cells. Such interfaces typically contain nanometer-size features for stimulation and recording as in cell-non-invasive extracellular microelectrode arrays. In such devices, it turns crucial to understand specific interactions of neural cells with physicochemical features of electrodes, which could be designed to optimize performance. Herein, versatile flexible nanostructured electrodes covered by arrays of metallic nanowires are fabricated and used to investigate the role of chemical composition and nanotopography on rat brain cells in vitro. By using Au and Ni as exemplary materials, nanostructure and chemical composition are demonstrated to play major roles in the interaction of neural cells with electrodes. Nanostructured devices are interfaced to rat embryonic cortical cells and postnatal hippocampal neurons forming synaptic circuits. It is shown that Au-based electrodes behave similarly to controls. Contrarily, Ni-based nanostructured electrodes increase cell survival, boost neuronal differentiation, and reduce glial cells with respect to flat counterparts. Nonetheless, Au-based electrodes perform superiorly compared to Ni-based ones. Under electrical stimulation, Au-based nanostructured substrates evoke intracellular calcium dynamics compatible with neural networks activation. These studies highlight the opportunity for these electrodes to excite a silent neural network by direct neuronal membranes depolarization.


Assuntos
Estimulação Elétrica/instrumentação , Nanotecnologia/instrumentação , Nanofios/química , Neurônios , Sinapses/fisiologia , Animais , Sinalização do Cálcio , Células Cultivadas , Córtex Cerebral/citologia , Desenho de Equipamento , Feminino , Hipocampo/citologia , Microeletrodos , Neurônios/citologia , Neurônios/fisiologia , Ratos , Ratos Wistar
10.
ACS Appl Mater Interfaces ; 12(35): 38962-38975, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32805917

RESUMO

Graphene oxide (GO) assists a diverse set of promising routes to build bioactive neural microenvironments by easily interacting with other biomaterials to enhance their bulk features or, alternatively, self-assembling toward the construction of biocompatible systems with specific three-dimensional (3D) geometries. Herein, we first modulate both size and available oxygen groups in GO nanosheets to adjust the physicochemical and biological properties of polycaprolactone-gelatin electrospun nanofibrous systems. The results show that the incorporation of customized GO nanosheets modulates the properties of the nanofibers and, subsequently, markedly influences the viability of neural progenitor cell cultures. Interestingly, the partially reduced GO (rGO) nanosheets with larger dimensions trigger the best cell response, while the rGO nanosheets with smaller size provoke an accentuated decrease in the cytocompatibility of the resulting electrospun meshes. Then, the most auspicious nanofibers are synergistically accommodated onto the surface of 3D-rGO heterogeneous porous networks, giving rise to fibrous-porous combinatorial architectures suitable for enhancing adhesion and differentiation of neural cells. By varying the chemical composition of the nanofibers, it is possible to adapt their performance as physical crosslinkers for the rGO sheets, leading to the modulation of both pore size and structural/mechanical integrity of the scaffold. Importantly, the biocompatibility of the resultant fibrous-porous systems is not compromised after 14 days of cell culture, including standard differentiation patterns of neural progenitor cells. Overall, in light of these in vitro results, the reported scaffolding approach presents not only an indisputable capacity to support highly viable and interconnected neural circuits but also the potential to unlock novel strategies for neural tissue engineering applications.


Assuntos
Grafite/química , Nanofibras/química , Engenharia Tecidual , Alicerces Teciduais/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Diferenciação Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Porosidade , Ratos , Ratos Wistar
11.
ACS Appl Mater Interfaces ; 12(4): 4295-4307, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31904927

RESUMO

We have developed a reproducible and facile one step strategy for the synthesis of doxorubicin loaded magnetoliposomes by using a thin-layer evaporation method. Liposomes of around 200 nm were made of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and iron oxide nanoparticles (NPs) with negative, positive, and hydrophobic surfaces that were incorporated outside, inside, or between the lipid bilayers, respectively. To characterize how NPs are incorporated in liposomes, advanced cryoTEM and atomic force microscope (AFM) techniques have been used. It was observed that only when the NPs are attached outside the liposomes, the membrane integrity is preserved (lipid melt transition shifts to 38.7 °C with high enthalpy 34.8 J/g) avoiding the leakage of the encapsulated drug while having good colloidal properties and the best heating efficiency under an alternating magnetic field (AMF). These magnetoliposomes were tested with two cancer cell lines, MDA-MB-231 and HeLa cells. First, 100% of cellular uptake was achieved with a high cell survival (above 80%), which is preserved (83%) for doxorubicin-loaded magnetoliposomes. Then, we demonstrate that doxorubicin release can be triggered by remote control, using a noninvasive external AMF for 1 h, leading to a cell survival reduction of 20%. Magnetic field conditions of 202 kHz and 30 mT seem to be enough to produce an effective heating to avoid drug degradation. In conclusion, these drug-loaded magnetoliposomes prepared in one step could be used for drug release on demand at a specific time and place, efficiently using an external AMF to reduce or even eliminate side effects.


Assuntos
Antineoplásicos/química , Preparações de Ação Retardada/química , Sistemas de Liberação de Medicamentos/métodos , Lipossomos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Preparações de Ação Retardada/farmacologia , Doxorrubicina/química , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/instrumentação , Liberação Controlada de Fármacos , Humanos , Campos Magnéticos , Nanopartículas/química
12.
ACS Biomater Sci Eng ; 6(4): 2401-2414, 2020 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33455347

RESUMO

Spinal cord injury (SCI) is characterized by the disruption of neuronal axons and the creation of an inhibitory environment for spinal tissue regeneration. For decades, researchers and clinicians have been devoting a great effort to develop novel therapeutic approaches which include the fabrication of biocompatible implants that could guide neural tissue repair in the lesion site in an attempt to recover the functionality of the nervous tissue. In this context, although fiberlike structures have been hypothesized to serve as a topographical guidance for axonal regrowth, work on the exploration of this type of materials is still limited for SCI. Aiming to develop such guidance platforms, we recently designed and explored in vitro reduced graphene oxide materials in the shape of microfibers (rGO-MFs). After preliminary studies to assess the feasibility of their implantation at the injured spinal cord in vivo, no evident signs of subacute local toxicity were noticed (10 days of implantation). In this work, we specifically examine for the first time the regenerative potential of these scaffolds, slightly modified in their fabrication for improved reproducibility, when chronically interfaced with a cervical spinal cord injury. After extensive characterization of their physicochemical properties and in vitro experiments with neural progenitor cells, their neural regenerative capacity in vivo is investigated in a rat experimental model of SCI after 4 months of implantation (chronic state). Behavioral tests involving the use of forelimbs are performed. Immunofluorescence studies evidence that rGO-MFs scaffolds foster the presence of neuronal structures along with blood vessels both within the epicenter and in the surroundings of the lesion area. Moreover, the inflammatory response does not worsen by the presence of this material. These findings outline the potential of rGO-MF-based scaffolds to promote regenerative features at the injured spinal cord such as axonal and vascular growth. Further studies including biological functionalization might improve their therapeutic potential by a synergistic effect of topographical and chemical cues, thus boosting neural repair after SCI.


Assuntos
Medula Cervical , Grafite , Animais , Ratos , Reprodutibilidade dos Testes , Medula Espinal
13.
Biomaterials ; 192: 461-474, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30502723

RESUMO

Neural diseases at the central nervous system including spinal cord injury (SCI) remain therapeutic challenges. Graphene materials are being delineated as alternative tools for neural repair. Herein, the regenerative ability of reduced graphene oxide (rGO) scaffolds to support pivotal features of neural repair at 4 months after SCI is assessed by an interdisciplinary approach. 3D randomly porous foams have been prepared in mechanical compliance with neural cells and tissues (Young's modulus of 1.3 ±â€¯1.0 kPa) as demonstrated by atomic force microscopy techniques applied ex vivo. After implantation, the significant increase in Young's modulus caused by massive cell/protein infiltration does not alter the mechanical performance of the contralateral spinal cord but provides mechanical stability to the lesion. These aerogels appear fully vascularized and populated with neurites, some of them being myelinated excitatory axons. Clinically-inspired magnetic resonance imaging studies demonstrate that the scaffolds significantly reduce perilesional damage with respect to rats without implants and cause no compressive damage in the contralateral hemicord and rostral/caudal regions. The rGO implants do not either alter the rat spontaneous behaviour or induce toxicity in major organs. Finally, preliminary data suggest hints of rGO sheets dissociation and eventual degradation at the injured spinal cord for the first time. In summary, these 3D porous rGO scaffolds are able to induce, without any further biological functionalization, a compilation of positive effects that have been rarely described before, if ever, for any other material implanted in the injured spinal cord.


Assuntos
Materiais Biocompatíveis/uso terapêutico , Grafite/uso terapêutico , Regeneração Nervosa , Traumatismos da Medula Espinal/terapia , Animais , Axônios/patologia , Materiais Biocompatíveis/química , Grafite/química , Masculino , Neovascularização Fisiológica , Ratos , Ratos Wistar , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/fisiopatologia , Alicerces Teciduais/química
14.
Int Arch Allergy Immunol ; 174(1): 1-6, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28950264

RESUMO

Hereditary angioedema (HAE) with C1 inhibitor deficiency is a genetic disorder that clinically manifests with attacks of angioedema in the subcutaneous and submucosal tissues, mainly in the extremities, abdomen, and upper airway. During attacks, vascular permeability is increased due to increased bradykinin (BK). This means that special therapies are needed for attacks that do not respond to traditional antiallergic therapies involving antihistamines, corticosteroids, and epinephrine. The recurring attacks may disable patients and lead to frequent visits to emergency rooms where misdiagnoses are common. HAE attacks may be fatal when upper-airway edema occurs, if proper treatment with a C1 inhibitor concentrate or BK receptor antagonist is not administered or an emergency tracheostomy is not performed. We propose a mnemonic method for the warning signs of HAE for the use as a diagnostic tool, i.e., the so-called "ABC" of the warning signs of HAE. The letters represent the following: A = Angioedema, B = Bradykinin, C = C1 inhibitor, D = Distress factors, E = Epinephrine nonresponsive, F = Family history, and G = Glottis/Gastrointestinal edema. To avoid fatalities, medical staff and patients, including family members, must be aware of HAE. An alphabetical mnemonic method has been developed and we hope it may benefit patients.


Assuntos
Angioedemas Hereditários/diagnóstico , Angioedemas Hereditários/tratamento farmacológico , Antagonistas dos Receptores da Bradicinina/uso terapêutico , Bradicinina/análogos & derivados , Proteínas Inativadoras do Complemento 1/deficiência , Angioedemas Hereditários/patologia , Bradicinina/metabolismo , Bradicinina/uso terapêutico , Permeabilidade Capilar/genética , Permeabilidade Capilar/fisiologia , Proteínas Inativadoras do Complemento 1/genética , Proteína Inibidora do Complemento C1 , Predisposição Genética para Doença/genética , Humanos , Receptores da Bradicinina/metabolismo
15.
Materials (Basel) ; 10(4)2017 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-28772715

RESUMO

The incorporation of multi-walled carbon nanotubes (MWCNTs) into chondroitin sulphate-based scaffolds and the effect on the structural, mechanical, conductive, and thermal properties of the resulting scaffolds is investigated. Three-dimensional hierarchical materials are prepared upon the application of the ice segregation-induced self-assembly (ISISA) process. The use of ice as structure-directing agents avoids chemicals typically used for this purpose (e.g., surfactants, block copolymers, etc.), hence, emphasising the green features of this soft-templating approach. We determine the critical parameters that control the morphology of the scaffolds formed upon ice-templating (i.e., MWCNTs type, freezing conditions, polymer and MWCNT concentration). MWCNTs are surface functionalized by acidic treatment. MWCNT functionalization is characterized by Raman, Fourier transfer infrared (FTIR) and X-ray Photoelectron (XPS) spectroscopies. Scanning electron microscopy (SEM) analysis and porosity studies reveal that MWCNT content modifies the morphology of the macroporous structure, which decreases by increasing MWCNT concentration. Differences in scaffold morphology should be translated into their conductivity and mechanical properties. As a general trend, the Young's modulus and the electrical conductivity of the scaffolds increase with the MWCNT content. Preliminary biocompatibility tests with human osteoblast-like cells also reveal the capability of these structures to support cell growth.

16.
Biomaterials ; 99: 72-81, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27214651

RESUMO

Attractive physic-chemical features of graphene oxide (GO) and promising results in vitro with neural cells encourage its exploration for biomedical applications including neural regeneration. Fueled by previous findings at the subacute state, we herein investigate for the first time chronic tissue responses (at 30 days) to 3D scaffolds composed of partially reduced GO (rGO) when implanted in the injured rat spinal cord. These studies aim to define fibrotic, inflammatory and angiogenic changes at the lesion site induced by the chronic implantation of these porous structures. Injured animals receiving no scaffolds show badly structured lesion zones and more cavities than those carrying rGO materials, thus pointing out a significant role of the scaffolds in injury stabilization and sealing. Notably, GFAP(+) cells and pro-regenerative macrophages are evident at their interface. Moreover, rGO scaffolds support angiogenesis around and, more importantly, inside their structure, with abundant and functional new blood vessels in whose proximities inside the scaffolds some regenerated neuronal axons are found. On the contrary, lesion areas without rGO scaffolds show a diminished quantity of blood vessels and no axons at all. These findings provide a foundation for the usefulness of graphene-based materials in the design of novel biomaterials for spinal cord repair and encourage further investigation for the understanding of neural tissue responses to this kind of materials in vivo.


Assuntos
Indutores da Angiogênese/uso terapêutico , Grafite/uso terapêutico , Neurônios/patologia , Óxidos/uso terapêutico , Traumatismos da Medula Espinal/terapia , Alicerces Teciduais/química , Indutores da Angiogênese/química , Animais , Axônios/metabolismo , Axônios/patologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/uso terapêutico , Grafite/química , Humanos , Imunomodulação , Masculino , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Óxidos/química , Ratos Wistar , Regeneração , Medula Espinal/irrigação sanguínea , Medula Espinal/patologia , Traumatismos da Medula Espinal/imunologia , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/cirurgia , Regeneração da Medula Espinal
17.
Adv Healthc Mater ; 4(12): 1861-8, 2015 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-26115359

RESUMO

The increasing prevalence and high sanitary costs of lesions affecting the central nervous system (CNS) at the spinal cord are encouraging experts in different fields to explore new avenues for neural repair. In this context, graphene and its derivatives are attracting significant attention, although their toxicity and performance in the CNS in vivo remains unclear. Here, the subacute tissue response to 3D flexible and porous scaffolds composed of partially reduced graphene oxide is investigated when implanted in the injured rat spinal cord. The interest of these structures as potentially useful platforms for CNS regeneration mainly relies on their mechanical compliance with neural tissues, adequate biocompatibility with neural cells in vitro and versatility to carry topographical and biological guidance cues. Early tissue responses are thoroughly investigated locally (spinal cord at C6 level) and in the major organs (i.e., kidney, liver, lung, and spleen). The absence of local and systemic toxic responses, along with the positive signs found at the lesion site (e.g., filler effect, soft interface for no additional scaring, preservation of cell populations at the perilesional area, presence of M2 macrophages), encourages further investigation of these materials as promising components of more efficient material-based platforms for CNS repair.


Assuntos
Grafite/química , Próteses e Implantes , Medula Espinal/metabolismo , Alicerces Teciduais/química , Animais , Sistema Nervoso Central/metabolismo , Masculino , Regeneração Nervosa , Neurônios/citologia , Neurônios/metabolismo , Óxidos/química , Ratos , Ratos Wistar
18.
J Mater Chem B ; 1(24): 3064-3072, 2013 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32261010

RESUMO

Carbon nanotubes (CNTs) have lately attracted significant attention in the field of biomedicine. Although a wide repertoire of CNT-based composites has been explored as substrates for cell growth, the fabrication of 3D scaffolds has been more rarely accomplished. Additionally, concerns referred to CNT biocompatibility make their use in biomaterials still controversial. Herein we explore the interaction of three types of CNT-based 3D scaffolds - prepared with multi-walled CNTs and processed to show different architectural and morphological features at the microscale by using three different polymers (i.e., chitosan, chondroitin sulphate and gelatin) - with three types of mammalian cells displaying different sizes and adhesion patterns. Cell-material interaction has been assessed by studying cell viability, adhesion, morphology, and apoptosis. By means of time-lapse confocal laser scanning microscopy, we investigate, for the first time in CNT-based scaffolds, cell migration processes in real time. Scaffolds displaying both a pore size in range with that of cells and lower surface roughness reveal the highest viability values. In contrast, those with a smaller pore size and higher surface roughness account for the lowest cytocompatibility. Results from these studies benefit the fabrication of optimized biomaterials by varying scaffold-dependent parameters in accordance with those of target cells. Furthermore, they may serve to anticipate the response of other cell types sharing similar characteristics to those described herein when in contact with CNT-based scaffolds.

19.
Int J Paediatr Dent ; 22 Suppl 1: 1-35, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22937908

RESUMO

OBJECTIVE: To provide the users with information on the current best practices for managing the oral health care of people living with EB. METHODS: A systematic literature search, in which the main topic is dental care in patients with Epidermolysis Bullosa, was performed. Consulted sources, ranging from 1970 to 2010, included MEDLINE, EMBASE, CINAHL, The Cochrane Library, DARE, and the Cochrane controlled trials register (CENTRAL). In order to formulate the recommendations of the selected studies the SIGN system was used. The first draft was analysed and discussed by clinical experts, methodologists and patients representatives on a two days consensus meeting. The resulting document went through an external review process by a panel of experts, other health care professionals, patient representatives and lay reviewers. The final document was piloted in three different centres in United Kingdom, Czech Republic and Argentina. RESULTS: The guideline is composed of 93 recommendations divided into 3 main areas: 1) Oral Care--access issues, early referral, preventative strategies, management of microstomia, prescriptions and review appointments 2) Dental treatment: general treatment modifications, radiographs, restorations, endodontics, oral rehabilitation, periodontal treatment, oral surgery and orthodontics, and 3) Anaesthetic management of dental treatment. CONCLUSIONS: A preventive protocol is today's dental management approach of choice.


Assuntos
Assistência Odontológica para Doentes Crônicos , Epidermólise Bolhosa/complicações , Anestesia Dentária , Assistência Odontológica Integral , Epidermólise Bolhosa/prevenção & controle , Educação em Saúde Bucal , Acessibilidade aos Serviços de Saúde , Humanos , Doenças da Boca/prevenção & controle , Higiene Bucal , Procedimentos Cirúrgicos Bucais , Encaminhamento e Consulta , Doenças Dentárias/prevenção & controle , Escovação Dentária
20.
Chem Soc Rev ; 41(14): 4996-5014, 2012 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-22695767

RESUMO

The aim of this review is to provide an exposition of some of the most recent applications of deep-eutectic solvents (DESs) in the synthesis of polymers and related materials. We consider that there is plenty of room for the development of fundamental research in the field of DESs because their compositional flexibility makes the number of DESs susceptible of preparation unlimited and so do the range of properties that DESs can attain. Ultimately, these properties can be transferred into the resulting materials in terms of both tailored morphologies and compositions. Thus, interesting applications can be easily envisaged, especially in those fields in which the preparation of high-tech products via low cost processes is critical. We hope that the preliminary work surveyed in this review will encourage scientists to explore the promising perspectives offered by DESs.

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