Fabrication of hierarchical porous DEGDA/hydroxyapatite composite scaffolds with biocompatibility via DLP 3D printing for enhanced mechanical strength

In the interdisciplinary field of materials science and biomedicine, three-dimensional (3D) printing, with its high speed and precision, has become a crucial technical means for processing biomaterials. Early research on biological 3D printing mainly focused on biocompatibility and cell viability, with relatively little attention paid to the mechanical properties of the structures. However, when porous structures are applied in the biomedical field, especially in bone tissue engineering, their inherent weak mechanical properties severely limit their application. In this study, digital light processing (DLP) technology was employed to fabricate 3D objects filled with hydroxyapatite (HAP) that possess hierarchical porous structures. HAP with bioactivity and osteoconductivity (0-2 wt%) endows the 3D printed products of the diethylene glycol diacrylate (DEGDA) composite material with a compressive strength of 2.9-5.8 MPa. Through further modification of HAP, the compressive strength of the hierarchical porous structure can reach up to approximately 8.96 MPa, which is an increase of about 53.88 % compared with the addition of the same content of unmodified HAP. At the same time, it also maintains a certain degree of biocompatibility, and its biodegradation rate can reach about 12 % within 30 days. This study has successfully achieved the DLP 3D printing of nanocomposites, providing a feasible, cost-effective, and customizable patient-specific solution for various fields in the biomedical industry.