Bioactive glass/polymer composite scaffolds mimicking bone tissue

Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
Journal of Biomedical Materials Research Part A (Impact Factor: 3.37). 10/2012; 100(10):2654-67. DOI: 10.1002/jbm.a.34205
Source: PubMed


The aim of this work was the preparation and characterization of scaffolds with mechanical and functional properties able to regenerate bone. Porous scaffolds made of chitosan/gelatin (POL) blends containing different amounts of a bioactive glass (CEL2), as inorganic material stimulating biomineralization, were fabricated by freeze-drying. Foams with different compositions (CEL2/POL 0/100; 40/60; 70/30 wt %/wt) were prepared. Samples were crosslinked using genipin (GP) to improve mechanical strength and thermal stability. The scaffolds were characterized in terms of their stability in water, chemical structure, morphology, bioactivity, and mechanical behavior. Moreover, MG63 osteoblast-like cells and periosteal-derived stem cells were used to assess their biocompatibility. CEL2/POL samples showed interconnected pores having an average diameter ranging from 179 ± 5 μm for CEL2/POL 0/100 to 136 ± 5 μm for CEL2/POL 70/30. GP-crosslinking and the increase of CEL2 amount stabilized the composites to water solution (shown by swelling tests). In addition, the SBF soaking experiment showed a good bioactivity of the scaffold with 30 and 70 wt % CEL2. The compressive modulus increased by increasing CEL2 amount up to 2.1 ± 0.1 MPa for CEL2/POL 70/30. Dynamical mechanical analysis has evidenced that composite scaffolds at low frequencies showed an increase of storage and loss modulus with increasing frequency; furthermore, a drop of E' and E″ at 1 Hz was observed, and for higher frequencies both moduli increased again. Cells displayed a good ability to interact with the different tested scaffolds which did not modify cell metabolic activity at the analyzed points. MTT test proved only a slight difference between the two cytotypes analyzed.

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Available from: Iva Pashkuleva, Oct 06, 2015
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    • "There are already examples of associations of gelatin and bioceramics , based e.g. on hydroxyapatite [6], b-tricalcium phosphate [7] and bioactive glasses [8] into promising 3D macroporous composite implants for bone regeneration. However, the synthesis of gelatin – bioactive glass composites is generally made by freezedrying processes [9] [10] and leads to limited and uncontrolled pore sizes with irregular pore shapes. To avoid such shortcomings, we have used the microsphere leaching technique [11]. "
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    ABSTRACT: Scaffolding materials are often needed for bone regeneration: their role is to act as temporary templates for the reconstruction of bone tissues either in situ or in the laboratory. Suitable properties for such scaffolds are bioactivity and mechanical toughness, which can both be combined in composite matrices based on bioceramics and biopolymers. Among possible combinations, bioactive glasses possess unique bone-bonding ability compared to other bioceramics, while gelatin is a biocompatible polymer naturally derived from collagen. Here we report the synthesis of bioactive glass–gelatin composite scaffolds with well-controlled porosity, which is a major concern as it can deeply influence osteogenesis. Compared to pure bioactive glass scaffolds, enhanced mechanical properties were observed, while the composite scaffolds still own promising in vitro bone-like apatite forming ability.
    Chemical Engineering Journal 11/2014; 256:9–13. DOI:10.1016/j.cej.2014.06.022 · 4.32 Impact Factor
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    • "Foams with three different weight ratios (BG/CG) between the components (S1: 0/100 w/w; S2: 40/60 w/w; S3: 70/30 w/w) were prepared. Details on mechanical properties, biocompatibility, and bioactivity of these scaffolds are described in previous study [14] "
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    ABSTRACT: The aim of the present study is to characterize the microstructure of composite scaffolds for bone tissue regeneration containing different ratios of chitosan/gelatin blend and bioactive glasses. Starting from realistic 3D models of the scaffolds reconstructed from micro-CT images, the level of heterogeneity of scaffold architecture is evaluated performing a lacunarity analysis.The results demonstrate that the presence of the bioactive glass component affects not only macroscopic features such as porosity, but mainly scaffold microarchitecture giving rise to structural heterogeneity, which could have an impact on the local cell-scaffold interaction and scaffold performances. The adopted approach allows to investigate the scale-dependent pore distribution within the scaffold and the related structural heterogeneity features, providing a comprehensive characterization of the scaffold texture.
    BioMed Research International 06/2014; DOI:10.1155/2014/161437 · 2.71 Impact Factor
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    ABSTRACT: 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-β1, and osteocalcin production, in agreement with the observed upregulation of ALP, OC, Runx2, and TGF-β1 gene in qPCR analysis, indicating that the composite scaffolds enhanced osteoblast activation and extra-cellular matrix mineralization processes. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
    Journal of Biomedical Materials Research Part A 12/2013; 101(12). DOI:10.1002/jbm.a.34662 · 3.37 Impact Factor
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