Abstract
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.
Highlights
IntroductionBulk scaffolds are capable of filling the missing segments and provide sufficient mechanical support for host bone immediately after implantation [1]
The main requirements of advanced materials for regenerative medicine are a hierarchical 3D architecture, a friendly interaction with biological tissues and promotion of tissue repair.For large bone defects, bulk scaffolds are capable of filling the missing segments and provide sufficient mechanical support for host bone immediately after implantation [1]
Cylindrical scaffolds were prepared by rolling up gelatin layers as depicted in Scheme 1
Summary
Bulk scaffolds are capable of filling the missing segments and provide sufficient mechanical support for host bone immediately after implantation [1]. They are preferred to other forms of materials (such as cements, injectable gels and membranes) for large bone defects [2]. Since native bone is a complex material with well-designed architecture, its successful integration and regeneration require that bone scaffolds support bone metabolism and be reabsorbed in situ, allowing the growth of the new tissue. Three-dimensional scaffolds mimicking the structure of extracellular matrix (ECM) provide the necessary support for cell attachment, growth and differentiation and define the overall shape of a bone tissue engineered transplant [3]. Inspired by the constituents of natural bone, a number of Molecules 2019, 24, 1931; doi:10.3390/molecules24101931 www.mdpi.com/journal/molecules
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