Core-shell nanospheres behind the blue eyes of the bay scallop Argopecten irradians .
Journal Article (Journal Article)
The bay scallop Argopecten irradians (Mollusca: Bivalvia) has dozens of iridescent blue eyes that focus light using mirror-based optics. Here, we test the hypothesis that these eyes appear blue because of photonic nanostructures that preferentially scatter short-wavelength light. Using transmission electron microscopy, we found that the epithelial cells covering the eyes of A. irradians have three distinct layers: an outer layer of microvilli, a middle layer of random close-packed nanospheres and an inner layer of pigment granules. The nanospheres are approximately 180 nm in diameter and consist of electron-dense cores approximately 140 nm in diameter surrounded by less electron-dense shells 20 nm thick. They are packed at a volume density of approximately 60% and energy-dispersive X-ray spectroscopy indicates that they are not mineralized. Optical modelling revealed that the nanospheres are an ideal size for producing angle-weighted scattering that is bright and blue. A comparative perspective supports our hypothesis: epithelial cells from the black eyes of the sea scallop Placopecten magellanicus have an outer layer of microvilli and an inner layer of pigment granules but lack a layer of nanospheres between them. We speculate that light-scattering nanospheres help to prevent UV wavelengths from damaging the internal structures of the eyes of A. irradians and other blue-eyed scallops.
Full Text
Duke Authors
Cited Authors
- Harris, OK; Kingston, ACN; Wolfe, CS; Ghoshroy, S; Johnsen, S; Speiser, DI
Published Date
- October 23, 2019
Published In
Volume / Issue
- 16 / 159
Start / End Page
- 20190383 -
PubMed ID
- 31640501
Pubmed Central ID
- 31640501
Electronic International Standard Serial Number (EISSN)
- 1742-5662
International Standard Serial Number (ISSN)
- 1742-5689
Digital Object Identifier (DOI)
- 10.1098/rsif.2019.0383
Language
- eng