Hydrogel-polymer hybrids are widely used across a variety of applications to form biomedical devices and flexible electronics. However, the technologies are presently limited to hydrogel-polymer hybrid laminates containing silicone rubbers. This can greatly limit the functionality and performance of hydrogel-polymer-based devices and machines. In a new study, Qi Ge, and a team of scientists in mechanics, mechatronic systems, flexible electronics, chemistry and advanced design in China, Singapore and Israel demonstrated a simple and versatile multi-material three-dimensional (3-D) printing approach. The method allowed the development of complex hybrid 3-D structures containing highly stretchable and high water content acrylamide—poly(ethylene glycol)diacrylate (PEGDA) abbreviated as AP hydrogels, covalently bonded with diverse ultraviolet (UV) curable polymers. The team printed the hybrid structures on a self-built digital-light processing (DLP)-based multi-material 3-D printer. They facilitated covalent bonding between the AP hydrogel and other polymers through incomplete polymerization initiated by a water-soluble photoinitiator. The team displayed a few applications based on this approach to propose a new way to realize multifunctional soft devices and machines by bonding hydrogel with diverse polymer in 3-D forms. The work is now published on Science Advances.