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

Abstract 

Objectives

To evaluate the effects of silica (SiO₂) (0.5wt%) and zinc oxide (ZnO) (0.25wt%) 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 β to α 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.

Keywords: β-Tricalcium phosphate, Porous scaffold, Three dimensional printing, Doped calcium phosphates, Bone tissue engineering