A paper entitled Supramolecular Lego Assembly Towards Three-Dimensional Multi-Responsive Hydrogels (DOI: 10.1002/adma.201402026) from Xie’s group has been published online in Advanced Materials.

Combining a material’s stimuli-responsiveness with relevant macroscopic three dimensional (3D) processing methods is essential for most high value added device applications of stimuli-responsive materials. Whereas much progress has been made on ever more complex stimuli-responsiveness of materials, processes for creating 3D complex shapes have remained scarce. We are, instead, inspired by another technique called Lego (a familiar toy) assembly as a highly versatile modular approach to construct 3D responsive material structures. Hydrogel building blocks with different responsiveness are assembled utilizing macroscopic host-guest recognition as the adhesion force. The Lego hydrogel can provide complex 3D upon pH or ionic strength variation. After disassembly of the building blocks by changing the oxidation state, they can be re-assembled into a completely new shape.