Multifunctionality of chiton biomineralized armor with an integrated visual system

Journal Article · Fri Nov 20 00:00:00 EST 2015 · Science

DOI:https://doi.org/10.1126/science.aad1246· OSTI ID:1237591

Li, Ling ^[1]; Connors, Matthew ^[2]; Kolle, Mathias ^[2]; England, Grant ^[3]; Speiser, Daniel ^[4]; Xiao, Xianghui ^[5]; Aizenberg, Joanna ^[3]; Ortiz, Christine ^[2]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Harvard Univ., Cambridge, MA (United States)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
3. Harvard Univ., Cambridge, MA (United States)
4. Univ. of South Carolina, Columbia, SC (United States)
5. Argonne National Lab. (ANL), Argonne, IL (United States)

Nature provides a multitude of examples of multifunctional structural materials. There are often trade-offs in these materials because few of them are equally well suited for multiple tasks. 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 lens. Here, we used optical experiments to demonstrate directly, for the first time, that these microscopic, mineralized lenses are able to form images. Furthermore, our experiments revealed that the optical performance of these polycrystalline lenses is enhanced by the reduction of spherical aberration through the shape of the lens and that birefringence scattering is minimized by the use of relatively large, co-aligned grains (~10 μm as compared to ~1 μm in the non-eye regions). Additionally, we used multi-scale mechanical testing techniques to show that A. granulata’s lenses are an integral component of its biomineralized armor, but that both the intrinsic and overall mechanical properties of the lenses are compromised as compared to the primary solid regions of the armor plates. Our results demonstrate that as the size, complexity, and functionality of the integrated sensory elements increases, the local mechanical performance of the armor decreases. But, A. granulata has evolved several strategies to compensate for its local mechanical vulnerabilities to form a multifunctional system with co-optimized overall optical and structural functions.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1237591
• Journal Information: Science, Vol. 350, Issue 6263; ISSN 0036-8075
• Publisher: AAAS
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE