Optimal structural characteristics of bone tissue engineering scaffolds from bionics and PSO-BP-NSGA III integrated algorithm

The repair of large segmental bone defects has always been a great challenge in clinical practice, and the stress-shielding is one of its core challenges. Here, based on the morphological similarity between natural trees and bone trabeculae, tree-like fractal biomimetic scaffolds were created. To optimize the synergy between high yield strength and low elastic modulus of the scaffold, the PSO-BP-NSGA Ⅲ integrated algorithm was employed. SLM 3D printing using Ti6Al4V and testing were conducted, and the test values were compared with those of the integrated algorithm. The tree-like fractal scaffold has the characteristic of radial gradient distribution of porosity similar to natural bone. The scaffolds can achieve effective synergy between yield strength and effective Young's modulus, such as the 2nd-order fractal scaffold, which has significant characteristics of high yield strength and low Young's modulus. The 2nd-order fractal scaffold exhibits favorable fluid flow gradient and permeability, with a comprehensive permeability of 3.13 × 10⁻⁸ m². The relative errors between the test and predicted values of yield strength and Young's modulus are 0.83% and 7.93% respectively, indicating that the PSO-BP-NSGA Ⅲ integrated algorithm has good predictive ability. This study proposes a novel design framework by combining bionics with the integrated algorithm.