Conjugates are provided herein which comprise a protein attached to at least two polymeric moieties, at least one of which exhibits reverse thermal gelation. The conjugates are suitable for being cross-linked by non-covalent and/or covalent cross-linking. Compositions-of-matter comprising cross-linked conjugates are provided herein, as well as processes for producing same. Methods of controlling a physical property of compositions-of-matter are also provided herein. The conjugates and compositions-of-matter may be used for various applications, such as cell growth, tissue formation, and treatment of disorders characterized by tissue damage or loss, as described herein.