The evolution of nitrocellulose as a material for bioassays

The need to improve health outcomes in the developing world and to moderate healthcare costs in developed countries has resulted in an increased interest in sophisticated, inexpensive, and instrument-free point-of-care diagnostics using porous materials. One major segment of the paper-based diagnostics effort is focused on developing high-performance point-of-care tests using porous nitrocellulose membranes. This review provides a perspective on the nature, history, and future of nitrocellulose-based assays. Beginning as a protein blotting substrate, porous nitrocellulose membranes have grown to be the most commonly used lateral flow substrate and are the primary membranes used in two-dimensional paper networks for user-friendly multistep assays. In addition to the historical context, we examine assay development considerations, such as the physics of flow in porous media, reagent deposition and storage, and detection methods.