In this new approach, cells are cultured in 3D on a paper scaffold by adding a hydrogel precursor, as a fluid containing suspended cells, to a paper support, allowing the cell-containing fluid to distribute through the paper by capillary wicking, gelling it in place, and then submerging the support in growth media. This simple procedure generates durable 3D fiber-supported gels with defined numbers and densities of cells with easily controlled lateral dimensions and with thickness defined by the paper. Individual layers can be easily manipulated and, if desired, stacked to form thicker multilayer constructs with dimensions that mimic the environment of cells in tissues, where the diffusion limited distribution of oxygen, nutrients, metabolites, and signaling molecules come into play. The stacked constructs may be designed to exhibit desired spatial distributions of cells, and can be easily destacked to analyze cell structure and function within physical sections of these 3D tissue-like structures without requiring optical or histological sectioning.

This paper-based cell-culture platform is readily integrated with cell-based assays and high-throughput screens for drug discovery. For example, multiple layers of paper can be incorporated into standard microwell plates by assembling multiple layers of paper, 96-zone plates, and commercially available bottomless 96-well plates. The platform could also be combined with existing technologies for the synthesis of chemical libraries on paper to provide for entirely new screening strategies. Finally, the platform is well-suited to co-culture screening strategies and tissue engineering experiments.