title: Multifunctionality of chiton biomineralized armor with an integrated visual system.
abstract: Nature provides a multitude of examples of multifunctional structural materials in which trade-offs are imposed by conflicting functional requirements. One such example is the biomineralized armor of the chiton Acanthopleura granulata, which incorporates an integrated sensory system that includes hundreds of eyes with aragonite-based lenses. We use optical experiments to demonstrate that these microscopic lenses are able to form images. Light scattering by the polycrystalline lenses is minimized by the use of relatively large, crystallographically aligned grains. Multiscale mechanical testing reveals that as the size, complexity, and functionality of the integrated sensory elements increase, the local mechanical performance of the armor decreases. However, A. granulata has evolved several strategies to compensate for its mechanical vulnerabilities to form a multipurpose system with co-optimized optical and structural functions.
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Connors
authors.affiliation: Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Mathias
authors.initials: M
authors.lastname: Kolle
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Grant T
authors.initials: GT
authors.lastname: England
authors.affiliation: Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Daniel I
authors.initials: DI
authors.lastname: Speiser
authors.affiliation: Experimental Facilities Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
authors.forename: Xianghui
authors.initials: X
authors.lastname: Xiao
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02138, USA. Kavli Institute for Bionano Science and Technology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Joanna
authors.initials: J
authors.lastname: Aizenberg
authors.affiliation: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA. cortiz@mit.edu.
authors.forename: Christine
authors.initials: C
authors.lastname: Ortiz
mesh_terms: D060105:Animal Shells / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D057005:Bioengineering; D002119:Calcium Carbonate / Q000737:chemistry*; D003461:Crystallography; D007908:Lens, Crystalline / Q000737:chemistry*; D049916:Polyplacophora / Q000737:chemistry* / Q000502:physiology*; D014785:Vision, Ocular
chemical_list: D001672:Biocompatible Materials; D002119:Calcium Carbonate