Achievement of cornea-like organizations in dense collagen i solutions: Clues to the physico-chemistry of cornea morphogenesis

Multiphoton and electron microscopic analyses show that acido-soluble collagen I prepared in 5 mM acetic acid (pH 3.5) at concentration above 45 mg mL^-1 spontaneously generates liquid crystal phases mimicking plywood organization found in cornea tissues. Those organizations extend for several hundred micrometers. Transmission electron microscopy reveals the presence of small nanofibrils organized in a complex phase, coupling overall smectic and cholesteric organizations together with local order. Those nanofibrils could be the mesogen elements giving rise to this plywood organization. These data provide clues to physico-chemical events that may take place in cornea morphogenesis in vivo. This result is invaluable for bioengineering fields, as this liquid crystal organization paves the way for the generation of collagen based bio-mimetic cornea matrices.