A joint team from Far Eastern Federal University (FEFU, Russia), the University of Geneva, the University of Lausanne (Switzerland), and the Swiss Federal Institute of Technology has produced a biodegradable nanocoating, using antimicrobial, self-cleaning, and antireflective properties. The team turned to artificial manufacturing methods to reproduce the nanocoating of the corneas of fruit flies, which are naturally designed to shield the insects’ eyes from atmospheric particles, as well as from the reflection of light. Members of the team, led by head of the Laboratory of Pharmacology of Natural Compounds in the School of Biomedicine of FEFU Vladimir Katanaev, said that, among other applications, the nanocoating could be used in the structural dyeing of textiles. In such an application, the nanocoating would change the color of the textiles depending on angle of view. Further applications include a metamaterials-based disguise coat, an antibacterial layer for individual medical implants, and a self-cleaning coating for contact lenses and windshields, Katanaev said. Reinforcing the nanocoating could also enable its function as a base for flexible, miniature transistor prototypes designed for electronics. The scientists used both direct and reverse bioengineering methods to construct the modeled cornea, first taking apart a protective outer layer and separating it into constituent components. They then reassembled the disconnected materials — retinin, a protein, and corneal wax, a lipid — in a room-temperature setting and covered the glass and plastic surfaces. Step-wise increases in magnification, from a macroscale image of a Drosophila (fruit fly) head to an atomic force microscopy image of a single nanostructure coating an ommatidial lens. Courtesy of Mikhail Kryuchkov, Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva; Department of Pharmacology and Toxicology, University of Lausanne. The mechanism underlying the protective nanostructure’s formation is a self-organizing process described as reaction-diffused by Alan Turing in 1952. The mechanism proved consistent with the mathematical modeling the researchers performed in developing the nanocoating and with the type of pattern formations on a zebra’s and a leopard’s fur. The new work represents the first established instance of Turing patterns at the nanoscale, though the nanocoating itself meets numerous and wide-ranging demands in industry and research. Nanocoatings can wrap around flat and certain multidimensional structures, and in some instances they give the coated materials antireflective, antibacterial, and hydrophobic qualities. Antireflective coatings, including those manufactured at much higher costs than that of the collaboration's, are already being applied to computer panels, glasses, and paintings to exclude light’s reflection and refraction. “We are able to produce the nanocoating in any required quantity given that its design is more cost-effective compared to the modern methods of manufacturing similar structures,” Katanaev said. “The work with natural components requires no special equipment nor significant energy consumption and constraints of chemical etching, lithography, and laser printing.” In forthcoming work, the researchers aim to enhance their nanocoating by constructing a model of 3D nanostructuring, with nanofunnels, nanocolumns, and nanorolls within the coating’s layer. The research was published in Nature (www.doi.org/10.1038/s41586-020-2707-9).