The present invention relates to a polymer-protein precursor molecule comprising albumin and at least two synthetic polymers covalently attached to said albumin, each of said at least two synthetic polymers having a functional group, said functional group being selected capable of cross-linking with a functional group of at least one other synthetic polymer, said at least one other synthetic polymer forming a part of at least one other polymer-protein precursor molecule at least one other polymer-protein precursor molecule which comprises albumin and at least two synthetic polymers covalently attached to said albumin, said cross-linking forming a scaffold.
