Methods and compositions for melanin synthesis

A method of synthesizing melanin comprising the steps of:

• preparing an aqueous two-phase system (ATPS) by dissolving 5-10 w/w % polyethylene glycol (PEG) and 10-20 w/w % dextran in an aqueous solution comprising a tyrosine substrate optionally protected with a cleavable protecting group on a side chain;
• centrifuging the ATPS to create an upper and a lower phase;
• collecting the upper phase comprising dextran-rich droplets dispersed in a PEG-rich continuous phase;
• adding tyrosinase to the collected upper phase;
• and
• waiting for the appearance of a dark brown color, indicating that the tyrosine substrate was enzymatically oxidized by the tyrosinase to form melanin within the dextran-rich droplets, wherein:
• if protected tyrosine is used, the method further comprises, following the addition of the tyrosinase, a step of cleaving the cleavable protecting group on the side chain of the protected tyrosine so as to obtain unprotected tyrosine;
• the PEG-rich continuous phase comprises a higher concentration of PEG than of dextran and the dextran-rich droplets comprise a higher concentration of dextran than of PEG;
• and
• the tyrosine substrate and the tyrosinase preferentially partition into the droplets.