RT Journal Article SR Electronic T1 Macro-to-nano scale investigation of the acorn barnacle Semibalanus balanoides: correlative imaging, biological form and function, and bioinspiration JF bioRxiv FD Cold Spring Harbor Laboratory SP 590158 DO 10.1101/590158 A1 R.L. Mitchell A1 M. Coleman A1 P. Davies A1 L. North A1 E.C. Pope A1 C. Pleydell-Pearce A1 W. Harris A1 R. Johnston YR 2019 UL http://biorxiv.org/content/early/2019/03/27/590158.abstract AB The naturally-forming calcareous exoskeletons of arthropods and molluscs afford a substantial degree of protection, stability and waterproofing, while developing in ambient conditions and exhibiting diverse microstructure-property relationships. Correlative imaging combines information from multiple modalities (physical-chemical-mechanical properties) at various length-scales (cm to nm) to understand complex biological materials across dimensions (2D-3D). Here, we have used numerous coupled systems: X-ray microscopy (XRM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), optical light microscopy (LM), and focused-ion beam (FIB-SEM) microscopy to ascertain the microstructural and crystallographic properties of the wall-plate joints in the barnacle Semibalanus balanoides. The interlocks between neighbouring plates (alae) allow barnacles to expand and grow whilst remaining sealed and structurally strong. LM, SEM and EBSD illustrate ala crystallographic functionally-graded orientations and microstructures, which has implications for microstructure formation and function in nature, natural strengthening and preferred oriented biomineralisation. Additionally, targeted XRM identified three-dimensional ala pore networks for the first time; targeted FIB-SEM nanotomography revealed the nano-morphology and orientation of pores, highlighting the multi-scale hierarchy of the plates. Understanding these features contributes towards an understanding of the structural architecture in barnacles, but also their consideration for bioinspiration of human-made materials. The work demonstrates that correlative methods spanning different length-scales, dimensions and modes enable the extension of structure-property relationships in materials to form and function of organisms.