Processing and characterization of hydroxyapatite/gelatin microspheres

Abstract

The crisis of organ donors is an urgent call to develop fully functional substitutes in a short time. Additive manufacture applied to tissue engineering (bioprinting) is a method under development that has an interesting future, but it has difficulties with cell viability and density. Injectable microspheres loaded with cells that can be incorporated into hydrogel inks may be an alternative route to tackle this problem. The present work is devoted to fabricate highly spherical gelatin-composite hydroxyapatite microspheres starting with a calcium phosphate cement precursor by the emulsion method, controlling the effect of the gelatin concentration and the liquid to powder ratio of the cement precursor in the form and size of the spheres. The produced spheres consolidated by the hydraulic conversion of α-TCP into hydroxyapatite and the gelation of gelatin. Microspheres with sizes ranging from 40 to 100 μm were successfully produced, incorporated in a hydrogel bionk and injected without clogging the printing nozzle. 3-dimensional self-supporting constructs were fabricated. SaOs-2 cells were seeded on the surface of the microcarriers to assess their functionality as cell carriers. However, the experiment was unsuccessful, which was attributed to the oil residues remaining from the fabrication process, this fact pointing to the need to define a more efficient method to purify the microcarriers after the emulsion process.