Accession Number:

ADA624025

Title:

Biomolecular Mechanisms of Adaptive Reflectance and Related Biophotonic Systems in Molluscs

Descriptive Note:

Final rept. 1 Jun 2010-31 Aug 2014

Corporate Author:

CALIFORNIA UNIV SANTA BARBARA

Personal Author(s):

Report Date:

2015-01-09

Pagination or Media Count:

18.0

Abstract:

We elucidated the complete biomolecular mechanism controlling dynamically tunable reflectance from skin cells of the squid, accomplishing all major objectives of our proposed research, with potential benefit to the Army in identifying new paths for improvements in lightweight solar cells, IR detectors, and recovery of waste heat through thermal photovoltaics. Accordion-like folds in the cell membrane filled with unique reflectin proteins form the lamellae of a tunable Bragg reflector. An acetylcholine neurotransmitter-triggered signal transduction cascade activates catalytic phosphorylation of specific amino acids in the reflectin proteins, driving conformational changes in the proteins that activate their condensation and hierarchical assembly. The resulting occlusion of the reflectins surface charges triggers an efflux of small ions across the lamellar membranes, subsequently inducing a Gibbs-Donnan equilibration that drives expulsion of water, shrinking the thickness and spacing of the Bragg lamellae. The result is a simultaneous increase in the intensity of reflectance and a progressive change of color of the reflected light. In related results suggesting a mechanism for improved efficiency of lightweight solar cells, we discovered that Mie-scattering from the reflectin-containing cells in Tridacnid giant clams redirects solar photons deep into the animal s tissues, increasing the efficiency of photosynthesis by endosymbiotic microalgae.

Subject Categories:

  • Biochemistry
  • Biology
  • Fiber Optics and Integrated Optics
  • Biomedical Instrumentation and Bioengineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE