Fig. 1.
Topological morphologies of sea urchin spine and its biomimetic scaffolds: Sea urchin spines' needle-like appearance and internal architecture of graded porosity. (A) The optical image shows the natural features of the sea urchin spine. (B) Micro-computed tomography (CT) images show internal graded porosity in horizontal view and longitudinal views. (C) SEM images present the delicate internal morphologies in (c1-c2) sectional views. (D) Schematic diagram of the position of porous scaffolds within the implant. (E) Biomimetic graded pentamode-based scaffolds. (F) Geometrical features of the graded density from longitudinal view and the tapering strut topology compared with the uniform struts in horizontal view.