Disclosed herein is a compositions-of-matter comprising a cross-linked polymer, the cross-linked polymer comprising a plurality of resilin polypeptide moieties, and at least one polymeric moiety covalently cross-linked to a plurality of the resilin polypeptide moieties via at least one cross-linking moiety, the cross-linking moiety being devoid of a biphenyl moiety. Further disclosed herein is a process for preparing the composition-of-matter, a composite material comprising the composition-of-matter and at least one additional polymeric substance bound to the cross-linked polymer, an article-of-manufacturing comprising the composition-of-matter and/or composite material, and a method of treating tissue damage or loss by implanting said article-of-manufacturing in a subject.