Implications for photonic applications of diatom growth and frustule nanostructure changes in response to different light wavelengths

Abstract

Diatoms are unicellular algae enclosed in intricate bio-silicified walls with repetitive nanostructures in a size range which makes them potentially relevant for a broad spectrum of industrial applications. How to optimize the nano-scale structures of the frustule for utilization of diatoms in nanotechnology is one of the technological challenges for these applications. Light is one of the most important abiotic factors for algal photosynthetic growth, and the frustule may play an important role in mediating light for these biological functions, as well as being central for its nano-technological applications. In this study, we tested the influence of light quality on the nanostructure of the frustule of Coscinodiscus granii and compared this to growth rate response. The results showed that colored light (red, yellow, green and blue) at 300 μmol photons m -2 ·s -1 resulted in a statistically significant change in nanostructure compared to white light. Green light at 100 μmol photon m -2 ·s -1 led to a significant decrease in mean frustule diameter and mean foramen diameter. Numerical simulations confirmed that the morphological changes obtained were sufficient to induce clear differences in the photonics properties of the frustule. The wavelength had no effect on the growth rate at high light intensity (300 μmol photons m -2 ·s -1 ). However, at 100 μmol photons m -2 ·s -1 , yellow, red-orange and green light resulted in significantly lower maximum growth rates than the other wavelengths. This response of the frustule structure to different light treatment indicates the possibility of a light-based frustule nanostructure manipulation method, which is simple and environmentally friendly.

Light and photosynthetic microalgae: A review of cellular- and molecular-scale optical processes

“…In ref. (Su et al 2015) diatoms grown under red, yellow, green and blue light at high intensity (300 µmol / m 2 s) expressed decreased foramen density, relative to white light. Cells grown under high intensity colored light had decreased foramen density relative to low intensity (100 µmol / m 2 s), whereas the opposite was true for white light.…”

“…In addition, there exists some interesting physiological changes as a response to wavelength of light. The synthesis of diatom frustule structure has been reported to depend on light intensity and color (Su et al 2017;Su et al 2015).…”

Effect of Light Intensity and Light Quality on Diatom Behavioral and Physiological Photoprotection

“…Ideally Qphar should be monitored continuously but is not the only chromatic effect of light and may sometime prove to be unadapted to quantitatively measure light. For instance, frustule nanostructure may change upon exposure to different monochromatic wavelengths (Su et al, 2015) consequently modifying photonic properties either in increasing blue light absorption by the frustule (Yamanaka et al, 2008) or in increasing blue light scalar irradiance thus enhancing the effective intensity of blue light (Goessling et al, 2018). Such effect would not be integrated in Qphar calculation.…”

Progress and Opportunities in Soft Photonics and Biologically Inspired Optics

“…Recent work aimed at elucidating photonic structure formation in butterflies in situ shows great promise for revealing the processes underlying formation of functional biological micro‐ and nanoarchitectures . Research aimed at modifying diatom growth and exploring diatoms' versatility in optical applications also is expected to provide significant insights and benefits for the development of optical technologies . While learning about the processes governing biological material formation, we also can hope to glean useful insight into strategies for advancing synthetic manufacture of photonic materials.…”