Enzymatic oxidation of tyrosine enantiomers into biomimetic pigments with enhanced performance for hair dyeing

Most natural biomolecules have two enantiomeric forms and can exist in either of them. Despite the L -type homochirality of natural biopolymers composed of amino acids, a great deal of effort has been devoted to the systems in which chirality dictates molecular self-assembly and corresponding properties. Previously, we demonstrated that chemical pre-modification of tyrosine ( L -Tyr) inspired by natural eumelanin can obtain colorful pigments and surface coatings , but their characteristics like stability still have development space. Here, the racemic reaction systems of tyrosine derivatives ( L/D -Tyr, Boc- L/D -Tyr and Cbz- L/D -Tyr) were designed, and we proved that substrate molecular chirality can affect the reaction rate of the oxidation process , change the intermolecular force and arrangement during assembly, thus influencing the morphology, structures, and properties of the biomimetic pigment materials. At the same time, we found that L + D -tyrosine derivatives can be oxidized and deposited on hair surfaces to obtain the color effect of black and red-brown series, and achieve green-safe biological hair dyeing. Compared with previous studies, it has faster coloring speed, higher color saturation, stronger color fixation stability, good mechanical strength and biocompatibility, providing a new idea for the manufacture of chiral-inspired advanced materials with bio-nanotechnology applications.