Characterization of the osteogenic differentiation capacity of human bone cells on hybrid β-TCP/ZrO2 structures

This study deals with synthetic biomaterials that are biocompatible and mechanically stable to serve as a potential bone graft for improved mandibular reconstruction. To fabricate novel hybrid scaffolds containing beta-tricalcium phosphate (β-TCP) and zirconia (ZrO2), 3D printing was combined with Freeze Foaming to achieve a certain porosity, mimicking cancellous bone. The aim was to characterize the differentiation capacity of human pre-osteoblasts on the hybrid scaffolds. Although a good biocompatibility was demonstrated for the tested components of the hybrid scaffold, pure β-TCP foams showed the best results regarding osteogenic differentiation and pro-inflammatory processes. To enhance the osteoinductive properties of the β-TCP foam, the structures were also biofunctionalized with bone morphogenic protein 2 (BMP-2) and its effect was analyzed either on single cell cultures of pre-osteoblasts or pre-osteoblasts directly co-cultured with human peripheral blood mononuclear cells (PBMCs). The latter served to analyze the induction of bone remodelling processes. The immobilization of BMP-2 on scaffolds and its biological accessibility could be demonstrated, however, the biofunctionalization did not result in an enhanced differentiation capacity and bone remodeling processes of either pre-osteoblasts or directly co-cultured pre-osteoblasts and PBMCs.