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ABSTRACT: Bioactive particles have been widely used in a series of biomedical applications due to their ability to promote bone-bonding and elicit favorable biological responses in therapies associated with the replacement and regeneration of mineralized tissues. In this work hierarchical architectures are prepared by an innovative methodology using SiO(2)-CaO sol-gel based nanoparticles. Inspired by colloidal crystals, spherical aggregates were formed on biomimetic superhydrophobic surfaces using bioactive glass nanoparticles (BG-NPs) able to promote bone regeneration. A highly ordered organization, a common feature of mineralized structures in Nature, was achieved at both nano- and microlevels, being the crystallization degree of the structures controlled by the evaporation rates taking place at room temperature (RT) or at 4 °C. The crystallization degree of the structures influenced the Ca/P ratio of the apatitic film formed at their surface, after 7 days of immersion in SBF. This allows the regulation of bioactive properties and the ability to release potential additives that could be also incorporated in such particles with a high efficiency. Such a versatile method to produce bioactive particles with controlled size and internal structure could open new possibilities in designing new spherical devices for orthopaedic applications, including tissue engineering.
Nanoscale 09/2012; 4(20):6293-7. · 5.91 Impact Factor
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ABSTRACT: Nanocomposite films based on a chitosan blend with bioactive glass nanoparticles (BG-NPs) with different formulations, namely SiO(2):CaO:P(2)O(5)(mol.%) = 55:40:5 and SiO(2):CaO:P(2)O(5):MgO(mol.%) = 64:26:5:5 were produced in order to develop systems with applicability in guided tissue regeneration. The zeta (ζ)-potential of the BG-NPs containing magnesium was found to be lower than the other formulation and the corresponding composite with chitosan was the most hydrophilic. The bioactive character of the biomaterials was also assessed in vitro by immersion of the materials in simulated body fluid, followed by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy evaluations. SaOs-2 osteoblastic-like cells were seeded on the different nanocomposites and their behavior was followed by SEM observations, cytotoxicity assessments, DNA quantification and alkaline phosphatase analysis. The introduction of the inorganic component in the chitosan matrix had a positive effect on the biological response of the membranes. The developed nanocomposite films are potential candidates for regenerating damaged bone tissue and could be useful in orthopedic and maxillo-facial applications.
Biomedical Materials 09/2012; 7(5):054104. · 2.16 Impact Factor
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ABSTRACT: Bioactive glass nanoparticles (BG-NPs) capable of inducing apatite precipitation upon immersion in simulated body fluid (SBF) were patterned on free-standing chitosan membranes by microcontact printing using a poly(dimethylsiloxane) (PDMS) stamp inked in a BG-NPs pad. Formation of the patterns was characterized by scanning electron microscopy (SEM). Mineralization of the bioactive glass patterns was induced in vitro by soaking the samples in SBF over different time points up to 7 days. The confined apatite deposition in the patterned regions with diameters of 50 μm was confirmed by Fourier-transformed infrared spectroscopy (FTIR), energy-dispersive X-ray (EDX) analysis, and SEM. In vitro tests confirmed the preferential attachment and proliferation of L929 cells to the areas printed with BG-NPs of the membranes. This approach permits one to spatially control the properties of biomaterials at the microlevel and could be potentially used in guided tissue regeneration for skin, vascular, articular, and bone tissue engineering and in cellular cocultures or to develop substrates able to confine cells in regions with controlled geometry at the cell's length scale.
Langmuir 04/2012; 28(17):6970-7. · 4.19 Impact Factor
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ABSTRACT: Bioactive glass nanoparticles (BG-NPs), based on both ternary (SiO(2)-CaO-P(2)O(5)) and binary (SiO(2)-CaO) systems, were prepared via an optimized sol-gel method. The pH of preparation and the effect of heat treatment temperature were evaluated, as well as the effect of suppressing P in the bioactivity ability of the materials. The morphology and composition of the BG-NPs were studied using FTIR, XRD and SEM. The bioactive character of these materials was accessed in vitro by analyzing the ability for apatite formation onto the surface after being immersed in simulated body fluid (SBF). XRD, EDX and SEM were used to confirm the bioactivity of the materials. The BG-NP effect on cell metabolic activity was assessed by seeding L929 cells with their leachables, proving the non-cytotoxicity of the materials. Finally the most bioactive BG-NPs developed (ternary system prepared at pH 11.5 and treated at 700 °C) were successfully combined with chitosan in the production of biomimetic nanocomposite osteoconductive membranes that could have the potential to be used in guided tissue regeneration.
Nanotechnology 11/2011; 22(49):494014. · 3.98 Impact Factor
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ABSTRACT: Mono-dispersed SiO(2)-CaO bioactive glass nanospheres (BGNS) were prepared by a two step sol-gel method in the absence of surfactant. The size of BGNS ranged from 200 to 350 nm in diameter and exhibited a rough surface texture. In vitro biomineralization tests showed that BGNS could rapidly induce the deposition of an apatite layer in simulated body fluid (SBF). The effect of bioactive glass on the biomechanical properties of various mammalian cells was first reported in this paper. Atomic force microscopy (AFM) was used for measuring the biomechanical properties of mammalian cells. The result showed that BGNS-medium could significantly decrease the plasma membrane stiffness of bone marrow stem cells (BMSCs) by ∼50% and stimulate BMSCs spreading. The effect of BGNS on biomechanical properties of bovine aortic endothelial cells (BAECs) was opposite to that on BMSCs. BGNS increased the BAECs' stiffness and stimulated the elongation of endothelial cells and the formation of endothelial networks, which might potentially facilitate the vascularization of implanted BGNS-based biomaterials in tissue engineering as a scaffold or as an injectable system.
Journal of Biomedical Materials Research Part A 12/2010; 95(3):747-54. · 2.63 Impact Factor
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ABSTRACT: The micro-architecture of nacre (mother of pearl) has been classically illustrated as a 'brick-and-mortar' arrangement. It is clear now that hierarchical organization and other structural features play an important role in the amazing mechanical properties of this natural nanocomposite. The more important structural characteristics and mechanical properties of nacre are exposed as a base that has inspired scientists and engineers to develop biomimetic strategies that could be useful in areas such as materials science, biomaterials development and nanotechnology. A strong emphasis is given on the latest advances on the synthetic design and production of nacre-inspired materials and coatings, in particular to be used in biomedical applications.
Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 05/2009; 367(1893):1587-605. · 2.77 Impact Factor
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ABSTRACT: Poly(l-lactic acid) superhydrophobic surfaces prepared by a phase-separation methodology were treated with 30 min exposition of UV/O3 irradiation using hollowed masks in order to obtain patterned superhydrophilic squared-shaped areas. These wettable areas successfully confined bioactive glass nanoparticles (BG-NPs), by dispensing and drying individual droplets of BG-NPs suspensions. The obtained biomimetic chips were used to test the in vitro bioactivity of binary (SiO2–CaO) and ternary (SiO2–CaO–P2O5) nanoparticles produced using sol–gel chemistry by immersing such substrate in simulated body fluid (SBF). From SEM and EDX it was possible to conclude that the ternary system promoted an enhanced apatite deposition. This work shows the potential of using such flat disposable matrices in combinatory essays to easily evaluate the osteoconductive potential of biomaterials using small amounts of different samples.
Materials Letters.
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ABSTRACT: Through the natural evolutionary process, organisms have been improving amazing mineralized materials for a series of functions using a relatively few constituent elements. Biomineralization has been widely studied in the last years. It is important to understand how minerals are produced by organisms and also their structure and the corresponding relationship with the properties and function. Moreover, one can look at minerals as a tool that could be used to develop high performance materials, through design inspiration and to find novel processing routes functioning at mild conditions of temperature, pressure and solvent type. As important as the molecular constituents are structural factors, which include the existence of different levels of organization and controlled orientation. Moreover, the way how the hierarchical levels are linked and interfacial features plays also a major role in the final behavior of the biogenic composite. The main aim of this work is to review the latest contributions that have been reported on composite materials produced in nature, and to relate their structures at different length scales to their main functions and properties. There is also an interest in developing new biomimetic procedures that could induce the production of calcium phosphate coatings, similar to bone apatite in substrates for biomedical applications, namely in orthopedic implants and scaffolds for tissue engineering and regenerative medicine; this topic will be also addressed. Finally, we also review the latest proposed approaches to develop novel synthetic materials and coatings inspired from natural-based nanocomposites.
Composites Science and Technology.
