Effects of silica and zinc oxide doping on mechanical and biological properties of 3D printed tricalcium phosphate tissue engineering scaffolds

Objectives. To evaluate the effects of silica (SiO2) (0.5 wt%) and zinc oxide (ZnO) (0.25 wt%) dopants on the mechanical and biological properties of tricalcium phosphate (TCP) scaffolds with three dimensionally (3D) interconnected pores. Methods. Scaffolds were created with a commercial 3D printer. Post sintering phase analysis was determined by X-ray diffraction. Surface morphology of the scaffolds was examined by field emission scanning electron microscopy (FESEM). Mechanical strength was evaluated with a screw driven universal testing machine. MTT assay was used for cellular proliferation characteristics and cellular morphology was examined by FESEM. Results. Addition of dopants into TCP increased the average density of pure TCP from 90.8 +/- 0.8% to 94.1 +/- 1.6% and retarded the beta to alpha phase transformation at high sintering temperatures, which resulted in up to 2.5 fold increase in compressive strength. In vitro cell-materials interaction studies, carried out using hFOB cells, confirmed that the addition of SiO2 and ZnO to the scaffolds facilitated faster cell proliferation when compared to pure TCP scaffolds. Significance. Addition of SiO2 and ZnO dopants to the TCP scaffolds showed increased mechanical strength as well as increased cellular proliferation. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.