Microfluidic devices fabricated from paper that has been covalently modified to increase its hydrophobicity, as well as methods of making and using thereof are provided herein. The devices are typically small, portable, flexible, and both easy and inexpensive to fabricate. Microfluidic devices contain a network of microfluidic components, including microfluidic channels, microfluidic chambers, microwells, or combinations thereof, designed to carry, store, mix, react, and/or analyze liquid samples. The microfluidic channels may be open channels, closed channels, or combinations thereof. The microfluidic devices may be used to detect and/or quantify an analyte, such as a small molecules, proteins, lipids polysaccharides, nucleic acids, prokaryotic cells, eukaryotic cells, particles, viruses, metal ions, and combinations thereof.
STATEMENT OF GOVERNMENT SUPPORT
 This work was supported by government support under DE-FG02-00ER45852 awarded by United States Department of Energy. The United States Government may have certain rights to this invention.