SLA-3d printing and compressive strength of PEGDA/nHAP biomaterials

Herein, poly (ethylene glycol) diacrylate (PEGDA)/nanohydroxyapatite (nHAP) biomaterials were prepared by stereolithography (SLA), rendering optimal compressive strength. PEGDA and photoinitiator I2959 were mechanically mixed with bioceramic nHAP to prepare a paste with simple composition, suitable viscosity, and excellent photocurable ability. The content of the photoinitiator in the paste was determined by the cytotoxicity of cured samples. Then, the solid content of paste and processing parameters were optimized by a uniform design experiment method according to the curing characteristics of PEGDA/nHAP paste and compressive strength of PEGDA/nHAP printed specimens. As a result, the minimum cured width of a single line of PEGDA/nHAP paste reached 65 pm on the XY plane, mainly influenced by laser power. The minimum cured depth of PEGDA/nHAP paste was found to be 150 pm, which was influenced by hatch spacing. The compressive strength of PEGDA/ nHAP-printed specimens reached a maximum of 61.0 +/- 3.9 MPa, which was about 1700% higher than pure PEGDA (3.6 +/- 0.9 MPa). SLA-prepared PEGDA/nHAP biomaterials can meet compressive strength requirements of bone tissue (2-80 MPa), showing promise in the field of bone regeneration.