Reverse and forward engineering of Drosophila corneal nanocoatings. Kryuchkov Mikhail,Bilousov Oleksii,Lehmann Jannis,Fiebig Manfred,Katanaev Vladimir L Nature Insect eyes have an anti-reflective coating, owing to nanostructures on the corneal surface creating a gradient of refractive index between that of air and that of the lens material. These nanocoatings have also been shown to provide anti-adhesive functionality. The morphology of corneal nanocoatings are very diverse in arthropods, with nipple-like structures that can be organized into arrays or fused into ridge-like structures. This diversity can be attributed to a reaction-diffusion mechanism and patterning principles developed by Alan Turing, which have applications in numerous biological settings. The nanocoatings on insect corneas are one example of such Turing patterns, and the first known example of nanoscale Turing patterns. Here we demonstrate a clear link between the morphology and function of the nanocoatings on Drosophila corneas. We find that nanocoatings that consist of individual protrusions have better anti-reflective properties, whereas partially merged structures have better anti-adhesion properties. We use biochemical analysis and genetic modification techniques to reverse engineer the protein Retinin and corneal waxes as the building blocks of the nanostructures. In the context of Turing patterns, these building blocks fulfil the roles of activator and inhibitor, respectively. We then establish low-cost production of Retinin, and mix this synthetic protein with waxes to forward engineer various artificial nanocoatings with insect-like morphology and anti-adhesive or anti-reflective function. Our combined reverse- and forward-engineering approach thus provides a way to economically produce functional nanostructured coatings from biodegradable materials. 10.1038/s41586-020-2707-9

[Optimization of retinin expression and the application with wax emulsion in nanocoatings]. Sheng wu gong cheng xue bao = Chinese journal of biotechnology Anti-reflective nanocoatings that mimic the eyes of fruit flies are biodegradable materials with great market potential for a variety of optical devices that require anti-reflective properties. Microbial expression of retinin provides a new idea for the preparation of nanocoatings under mild conditions compared to physicochemical methods. However, the current expression level of retinin, the key to anti-reflective coating, is low and difficult to meet mass production. In this study, we analyzed and screened the best expression hosts for -derived retinin protein, and optimized its expression. Chinese hamster ovary (CHO) cells were identified as the efficient expression host of retinin, and purified retinin protein was obtained. At the same time, the preparation method of lanolin nanoemulsion was explored, and the best anti-reflective ability of the nano-coating was determined when the ratio of specific concentration of retinin protein and wax emulsion was 16:4, the pH of the nano-coating formation system was 7.0, and the temperature was 30 ℃. The enhanced antireflective ability and reduced production cost of artificial antireflective nanocoatings by determining the composition of nanocoatings and optimizing the concentration, pH and temperature of system components may facilitate future application of artificial green degradable antireflective coatings. 10.13345/j.cjb.230119

Tailoring surface properties of liposomes for dexamethasone intraocular administration. Journal of controlled release : official journal of the Controlled Release Society Diseases of the posterior eye segment are often characterized by intraocular inflammation, which causes, in the long term, severe impairment of eye functions and, ultimately, vision loss. Aimed at enhancing the delivery of anti-inflammatory drugs to the posterior eye segment upon intravitreal administration, we developed liposomes with an engineered surface to control their diffusivity in the vitreous and retina association. Hydrogenated soybean phosphatidylcholine (HSPC)/cholesterol liposomes were coated with (agmatinyl)-maltotriosyl-acetamido-N-(octadec-9-en-1-yl)hexanamide (Agm-M-Oleate), a synthetic non-peptidic cell penetration enhancer (CPE), and/or 5% of mPEG-DSPE. The zeta potential of liposomes increased, and the mobility in bovine vitreous and colloidal stability decreased with the Agm-M-Oleate coating concentration. Oppositely, mPEG-DSPE decreased the zeta potential of liposomes and restored both the diffusivity and the stability in vitreous. Liposomes with 5 mol% Agm-M-Oleate coating were well tolerated by ARPE-19 retina cells either with or without mPEG-DSPE, while 10 mol% Agm-M-Oleate showed cytotoxicity. Agm-M-Oleate promoted the association of liposomes to ARPE-19 cells with respect to plain liposomes, while mPEG-DSPE slightly reduced the cell interaction. Dexamethasone hemisuccinate (DH) was remotely loaded into liposomes with a loading capacity of ∼10 wt/wt%. Interestingly, mPEG-DSPE coating reduced the rate of DH release and enhanced the disposition of Agm-M-Oleate coated liposomes in the ARPE-19 cell cytosol resulting in a more efficient anti-inflammatory effect. Finally, mPEG-DSPE enhanced the association of DH-loaded Agm-M-Oleate coated liposomes to explanted rat retina, which reflected in higher viability of inner and outer nuclear layer cells. 10.1016/j.jconrel.2023.01.027