Preparation and properties of T-ZnOw enhanced BCP scaffolds with double-layer structure by digital light processing

Abstract Bone scaffolds require both good bioactivity and mechanical properties to keep shape and promote bone repair. In this work, T-ZnO w enhanced biphasic calcium phosphate (BCP) scaffolds with triply periodic minimal surface (TPMS)-based double-layer porous structure were fabricated by digital light processing (DLP) with high precision. Property of suspension was first discussed to obtain better printing quality. After sintering, T-ZnO w reacts with β-tricalcium phosphate (β-TCP) to form Ca 19 Zn 2 (PO 4 ) 14 , and inhibits the phase transition to α-TCP. With the content of T-ZnO w increasing from 0 to 2 wt%, the flexural strength increases from 40.9 to 68.5 MPa because the four-needle whiskers can disperse stress, and have the effect of pulling out as well as fracture toughening. However, excessive whiskers will reduce the cure depth, and cause more printing defects, thus reducing the mechanical strength. Besides, T-ZnO w accelerates the deposition of apatite, and the sample with 2 wt% T-ZnO w shows the fastest mineralization rate. The good biocompatibility has been proved by cell proliferation test. Results confirmed that doping T-ZnO w can improve the mechanical strength of BCP scaffolds, and keep good biological property, which provides a new strategy for better bone repair.