The present invention provided for a novel process of forming silk fibroin gels, and controlling the rate of β-sheet formation and resulting hydrogelation kinetics, by vortex treatment of silk fibroin solution. In addition, the vortex treatment of the present invention provides a silk fibroin gel that may be reversibly shear-thinned, enabling the use of these approach for precise control of silk self-assembly, both spatially and temporally. Active agents, including biological materials, viable cells or therapeutic agents, can be encapsulated in the hydrogels formed from the processes, and be used as delivery vehicles. Hence, the present invention provide for methods for silk fibroin gelation that are useful for biotechnological applications such as encapsulation and delivery of active agents, cells, and bioactive molecules.