Robotic deposition and in vitro characterization of 3D gelatinbioactive glass hybrid scaffolds for biomedical applications

The development of inorganicorganic hybrid scaffolds with controllable degradation and bioactive properties is receiving considerable interest for bone and tissue regeneration. The objective of this study was to create hybrid scaffolds of gelatin and bioactive glass (BG) with a controlled, three-dimensional (3D) architecture by a combined solgel and robotic deposition (robocasting) method and evaluate their mechanical response, bioactivity, and response to cells in vitro. Inks for robotic deposition of the scaffolds were prepared by dissolving gelatin in a solgel precursor solution of the bioactive glass (70SiO225CaO5P2O5; mol%) and aging the solution to form a gel with the requisite viscosity. After drying and crosslinking, the gelatinBG scaffolds, with a grid-like architecture (filament diameter approximate to 350 mu m; pore width approximate to 550 mu m), showed an elastoplastic response, with a compressive strength of 5.1 +/- 0.6 MPa, in the range of values for human trabecular bone (212 MPa). When immersed in phosphate-buffered saline, the crosslinked scaffolds rapidly absorbed water (approximate to 440% of its dry weight after 2 h) and showed an elastic response at deformations up to approximate to 60%. Immersion of the scaffolds in a simulated body fluid resulted in the formation of a hydroxyapatite-like surface layer within 5 days, indicating their bioactivity in vitro. The scaffolds supported the proliferation, alkaline phosphatase activity, and mineralization of osteogenic MC3T3-E1 cells in vitro, showing their biocompatibility. Altogether, the results indicate that these gelatinBG hybrid scaffolds with a controlled, 3D architecture of inter-connected pores have potential for use as implants for bone regeneration. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.