Self-assembly properties of melanin and evolution of natural photonic crystals

The field of biomimetic design is promising for the creation of synthetic materials with multifaceted properties. Colour producing structures are currently under scrutiny from an engineering perspective. Despite the great interest, the natural processes involved in their creation, functionality and evolutionary relationships are not fully understood. 

This research will explicitly assess the stability and fossilisation potential of invertebrate pigments and the role in the formation of colour producing structures, such as photonic crystals. The study of animal integument as a composite material is currently highly active but to date these studies are focused on the material properties isolated from pigment content. Whilst this action aspires to answer palaeontological questions, it will also highlight a new growth area for materials sciences with numerous applications in aerospace, aircraft components and bioengineered medical materials, with industries worth over several billion of sales a year and will potentially benefit the quality of life of millions of people. Objectives. This proposal has four primary objectives: 1) To explore the morphology, self-assembly properties, and chemistry of melanin molecules in the integument invertebrate animals. 2) To investigate the potential for preservation of photonic structures in the fossil record of invertebrates and the optical characteristics after fossilization. 3) To develop a procedure for the creation of bioinspired materials in vitro and recreation of the fossilization process in laboratory-controlled conditions. 4) To investigate the evolutionary pathways and time of acquisition of pigment molecules as means of visual display and/or mechanical support and to elucidate the original functionality in the integument of invertebrates. Methodology. This is a multidisciplinary proposal, which integrates a diverse and innovative combination of novel and cutting-edge techniques allowing for a renewed view of the taphonomical processes that influence the preservation of colouration mechanisms in the fossil record of invertebrates. Approaching this poorly understood process via conventional experimental methodology, combined with state-of-the-art techniques more commonly used in other scientific fields, such as engineering, will allow for a completer and more accurate image of ancient communities. 

NXCT facilities used, Zeiss Versa 620 – Characterisation of photonic crystals and association to melanin molecules: Digital 3D reconstructions of the ultrastructure of natural photonic crystals in modern and fossil invertebrates is being built based on X-ray micro tomography (μCT) data.