Design of biomedical gradient porous scaffold via a minimal surface dual-unit continuous transition connection strategy

In this work, a series of new gradient porous scaffolds were innovatively designed via a dual-unit continuous transition connection strategy based on the minimal surface structures (primitive [P], diamond [D], and gyroid [G]). The scaffolds were successfully prepared through selective laser melting technology. The results showed that the dual-unit continuous transition connection strategy significantly improved the mechanical properties of the connected scaffolds. The compression strength of the scaffolds was found to be (P-G)>(P-D)>(G-P)>(G-D)>(D-G)>(D-P), with the P-G structure exhibiting a compression strength of 167.7 MPa and an elastic modulus of 3.3 GPa. The mechanical properties of the porous scaffolds were primarily influenced by the outer unit type, the connection condition between different units, the unit size, and the porosity. Scaffolds with the outer P unit demonstrated better mechanical properties due to the higher mechanical strength of the P structure. The connection performance between different units varied, with P and G units forming a good continuous transition connection, while the connection performance between P and D units was the weakest. The dual-unit continuous transition connection strategy offers a promising approach to optimize the connection performance of different units, providing new insights into the design of medical porous scaffolds.