Living in three dimensions

Research focused on deciphering the biochemical mechanisms that regulate cell proliferation and function has largely depended on the use of tissue culture methods in which cells are grown on two-dimensional (2D) plastic or glass surfaces. However, the flat surface of the tissue culture plate represents a poor topological approximation of the more complex three-dimensional (3D) architecture of the extracellular matrix (ECM) and the basement membrane (BM), a structurally compact form of the ECM. Recent work has provided strong evidence that the highly porous nanotopography that results from the 3D associations of ECM and BM nanofibrils is essential for the reproduction of physiological patterns of cell adherence, cytoskeletal organization, migration, signal transduction, morphogenesis, and differentiation in cell culture. In vitro approximations of these nanostructured surfaces are therefore desirable for more physiologically mimetic model systems to study both normal and abnormal functions of cells, tissues, and organs. In addition, the development of 3D culture environments is imperative to achieve more accurate cell-based assays of drug sensitivity, high-throughput drug discovery assays, and in vivo and ex vivo growth of tissues for applications in regenerative medicine.