Novel ceramic bone replacement material CeraBall seeded with human mesenchymal stem cells.

Hydroxyapatite (HA) and tricalcium phosphate (TCP) are two very common ceramic materials for bone replacement. A recently developed material for bone replacement is CeraBall, which is a mixed HA-TCP scaffold available as porous spherical scaffolds of diameter 4 and 6 mm. Before their use as bone replacement materials in vivo, in vitro testing of these scaffolds is necessary. The goal of this study was to characterise 4 and 6 mm CeraBall scaffolds in vitro with a view to their future use as bone replacement materials. The proliferation of human mesenchymal stromal cells (hMSCs) seeded on CeraBall scaffolds was evaluated quantitatively using the WST [Water soluble tetrazolium ((4-[3-(4- Iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate)] test and qualitatively by scanning electron microscopy (SEM). In addition, the standard MTT [(3-(4, 5-Dimenthylthiazol-2-Y1)-2, 5-Diphenyltetrazolium bromide)] biocompatibility test and cell vitality staining were performed using hMSCs. CeraBall scaffolds were also tested for their mechanical properties. SEM and WST test results showed that hMSCs proliferated on CeraBall scaffolds over the course of 9 days. Proliferation was similar to that seen on tissue culture polystyrene (control). Cells showed a well-spread morphology and formed 'sheets' on the surface of scaffolds. Invasion of pores was observed. Good biocompatibility was demonstrated by MTT test results and cell vitality staining. Scaffolds of both 4 and 6 mm were able to withstand compressive loads of 5 N. CeraBall scaffolds show good biocompatibility in vitro for hMSCs. This opens the way for in vivo applications.