Biomolecular Mechanisms of Adaptive Reflectance and Related Biophotonic Systems in Molluscs
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 09, 2015
- Accession Number
- ADA624025
Entities
People
- Daniel E Morse
Organizations
- University of California, Santa Barbara