Alt text
Figure 1: Structural characteristics of ACBSs. (a, b) SEM images of ACBSs at low magnification, digital photograph of the bivalves (inside (b)). (c) TEM image of ACBSs at low magnification. SEM images of ACBSs: (d, g, j) external surface, (f, i, l) internal surface. (e, h) ACBSs model with a green external surface, a blue internal surface, and a red boundary. (k) Sectional surface: red line shows the boundary of external and internal surfaces.