Enabling natural photonics through genetic manipulation of diatoms

Photonics, the manipulation of light at nanoscale, is a key enabling technology with potential to address a number of societal and global challenges. Photonic crystals (PhCs) are key components of photonic technologies facilitating light manipulation even in three dimensions; however, the nanofabrication procedures required are far from being environmentally friendly and cost-effective. The ENIGMA team recently demonstrated that diatoms, which are unicellular microalgae, form high-quality PhCs in their silica-based cell wall, with highly reproducible photonic properties in the visible spectral range. Thus, diatoms have potential to act as a platform for producing highly cost-effective, environmentally friendly and natural PhCs for a wide range of applications. In this project, we will combine biotechnology and nanophotonics to obtain tailored bio-PhCs for specific applications. We will sequence the silicon-responsive transcriptome of two diatom species, Coscinodiscus granii and C. wailesii, and establish genetic transformation in these species. We will use the data from Coscinodiscus and from the model diatom Thalassiosira pseudonana to identify candidate genes involved in the PhC formation process. Their function will be investigated using CRISPR/Cas9-based gene editing. The optical properties of the gene edited mutants will be characterized with microscopes adapted for the study of PhCs, yielding information of the spatial and spectral light manipulation potential, and to find a correlation between photonic response and genetic mutation. We will demonstrate the wide range of applicability of this novel technology through the implementation of two applications demanding high quality nanostructures; biosensing and photocatalytic platforms. Responsible Research and Innovation (RRI) will be employed in the project to ensure societal awareness, acceptability, and environmental sustainability.