Proc. Natl Acad. Sci. USA http://doi.org/9pr (2015)

When designing tissue scaffolds for regenerating tissues with complex forms, established technologies such as electrospinning and mould-casting are at a disadvantage. Three-dimensional printing approaches are evidently better suited to the task, yet they impose limitations on the choice of materials and can negatively affect cell viability. Su-Hwan Kim et al. now show that scaffolds based on paper offer an attractive alternative. By taking advantage of the capabilities of paper origami and of vapour-based thin-film coating methods, the researchers coated tissue-like paper forms with cell-encapsulating alginate hydrogels to make scaffolds with pre-designed shapes and spatially arranged cell patterns (through the use of pre-patterned moulds placed on top of the paper). They also show that a cylindrical hydrogel-laden paper scaffold bearing articular chondrocytes regenerated a trachea defect in rabbits without the need to use sutures, and with no signs of tissue granulation or significant narrowing of the airway four weeks after transplantation.