The present disclosure relates to an apparatus and process for forming medical devices from an injectable composition. The apparatus includes a supply assembly, a mixing assembly, and at least one source of microwave energy. The supply assembly is configured to maintain and selectively dispense a first precursor functionalized with a first reactive member and a second precursor functionalized with a second reactive member. The mixing assembly is configured to mix the first and second precursors within a mixing cavity defined therein. The microwave energy source is configured and adapted to irradiate the mixed first and second precursors within the mixing cavity.