January 2021
Vol 7, Issue 2

About The Cover

Cover image expansion

ONLINE COVER Hydrogel-polymer hybrids are used for a wide variety of applications, including biomedical devices and flexible electronics. However, these useful materials have their limits—current technologies are constrained to laminates, which consist of fixed layers of hydrogel and silicone rubbers. To explore a more versatile way to fabricate complex hydrogel-polymer hybrids, Ge et al. developed a multimaterial 3D printing approach, which involved a self-built 3D printer based on digital light processing (DLP). The researchers applied this approach to construct hybrid 3D structures consisting of highly stretchable acrylamide-PEGDA (AP) hydrogels with high water content, which were covalently bonded with diverse UV curable polymers. Ge et al. demonstrated that the technique could be used for applications including a 3D printed meniscus with spatially variable stiffness and a 4D printed cardiovascular stent capable of performing drug delivery. Ge et al. suggest this approach introduces a new way to build multifunctional soft devices and machines, with the potential to impact biomedicine, soft robotics, flexible electronics, and other fields. [CREDIT: QI GE]