Two-Dimensional Paper Networks for Automated Multistep Processes in Point-of-Care Diagnostics *

This chapter discusses the recent work from the collaboration of Fu, Lutz, and Yager, using two-dimensional paper networks (2DPNs) for automated multistep sample processing for high-sensitivity assays. The ability to perform multiple automated processing steps enables a host of capabilities that can be implemented in 2DPNs for higher performance testing at the point of care. A 2DPN can be used to create a paper dilution circuit that mixes two fluids and allows control over the dilution factor by simply changing the shape of the paper. The significant advantages of the 2DPN H-filter are that it is pumpless, fully disposable, and much cheaper than any previous implementations using conventional microfluidics. The overall challenge in point-of-care diagnostics development continues to be to create high-performance assays that are appropriate for the various multiconstraint settings relevant for global health applications.