The Diatom Staurosirella pinnata for Photoactive Material Production

Abstract

A native isolate of the colonial benthic diatom Staurosirella pinnata was cultivated for biosilica production. The silicified cell walls (frustules) were used as a source of homogeneous and structurally predictable porous biosilica for dye trapping and random laser applications. This was coupled with the extraction of lipids from biomass showing potential to fabricate photoactive composite materials sustainably. The strain was selected for its ease of growth in culture and harvesting. Biosilica and lipids were obtained at the end of growth in indoor photobioreactors. Frustules were structurally characterized microscopically and their chemistry analyzed with Fourier Transform Infrared Spectroscopy. Frustule capacity of binding laser dyes was evaluated on a set of frustules/Rhodamine B (Rho B) solutions and with respect to silicon dioxide and diatomite by Fluorescence Spectroscopy demonstrating a high affinity for the organic dye. The effect of dye trapping property in conveying Rho B emission to frustules, with enhancement of scattering events, was analyzed on Rho B doped polyacrylamide gels filled or not with frustules. Amplified spontaneous emission was recorded at increasing pump power indicating the onset of a random laser effect in frustule filled gels at lower power threshold compared to unfilled matrices.

UV-shielding and wavelength conversion by centric diatom nanopatterned frustules

“…Furthermore, the similarity of these structures to artificial photonic crystals led to the study of their ability to manipulate light 14 – 19 . Potential exploitation of optical, mechanical and structural properties of diatom frustules has been predicted and tested in several fields: design and development of highly efficient solar cells 20 – 22 ; plasmonics and Surface Enhanced Raman Spectroscopy (SERS) 23 – 25 ; sub-diffractive optics 26 ; photoluminescence-based sensors and biosensors 27 , 28 ; molding in micro- and nano- devices fabrication 29 ; nanovectoring of therapeutic agents in cancer cells 30 , 31 ; random lasing and dye trapping 32 , 33 , with several further innovative applications repeatedly envisaged 34 .…”

Genome-enabled phylogenetic and functional reconstruction of an araphid pennate diatom Plagiostriata sp. CCMP470, previously assigned as a radial centric diatom, and its bacterial commensal

“…The whole genome sequence of CCMP470 is the first representative of a staurosiroid diatom, and is also the first marine araphid pennate diatom genome available after that of the freshwater species Synedra acus 25 . These groups include potentially important contributors in estuarine, coastal and open-ocean assemblages, as well as model systems for bioindustrial cultivation 54,55 , which were previously only represented by one MMETSP transcriptome. CCMP470 may emerge as a useful model system for this clade as it can be kept clonally for long time periods: it has survived in culture since 1972 with no obvious size changes (presumably consistent with changes in physiology), sexual reproduction, or auxosporulation.…”

Culturing Toxic Benthic Blooms: The Fate of Natural Biofilms in a Microcosm System

“…ovata cells are clearly visible in the median part of the uppermost images ( a,b, arrows ) showing numerous, elongated chloroplasts located at the cell periphery. Green signal was obtained with a 488-nm laser source, emission of frustule autofluorescence [ 39 , 40 ] is visible in ( a, asterisk ) where elongated diatoms occurr sparse on the slide, while a dense cluster of Coscinodiscus sp. lies interspersed with thin cyanobacterial trichomes in ( d ).…”