a lead-specific DNAzyme. In contrast, polymerization embeds conductive polymers, which have high energy density and electrical stability, into the fibers of the paper device. While this technique has been used in the development of paper electronics, its adoption in paper-based microfluidics has been slower than in-situ seed growth. One research group embedded p-toluenesulfonic acid doped polypyrrole (i.e., polymer) into the channels of their paper-based microfluidic device, developing a self-powered paper circuit board when the channels were filled with a salt solution. Due to this polymerization technique, the paper microfluidic device could be folded using origami, allowing for both horizontal and vertical electroconductivity. Applications The main advantage of paper-based microfluidic devices over traditional microfluidics devices is their potential for use in the field rather than in a laboratory. Filter paper is advantageous in a field setting because it is capable of removing contaminants from the sample and preventing them from moving down the microchannel. This means that particles will not inhibit the accuracy of paper-based assays when they are used outdoors. Paper-based microfluidic devices are also small in size (approximately a few mm to 2 cm in length and width) compared to other microfluidic platforms, such as droplet-based microfluidic devices, which often use glass slides up to 75 mm in length. Because of their small size and relatively durable material, paper-based microfluidic devices are portable. Paper-based devices are also relatively inexpensive. Filter paper is very cheap, and so are most of the patterning agents used in the fabrication of microchannels, including PDMS and wax. Most of the major paper-based fabrication methods also do not require expensive laboratory equipment. These characteristics of paper-based microfluidics make it ideal for point-of-care testing, particularly in countries that lack advanced medical diagnostic tools. Paper-based microfluidics has also been used to conduct environmental and food safety tests. The main issues in the application of this technology are the lack of research into the flow control techniques, accuracy, and precision, the need for simpler operator procedures in the field, and the scaling of production to meet the volume requirements of a global market. This is largely due to the focus in the industry on utilizing the current silicon based manufacturing channels to commercialized LOC technologies more efficiently and economically. Paper-based microfluidics for diagnostics The original goal for paper-based microfluidics (μPAD) was to make low-cost and user-friendly point-of-care (POC) devices that can be operated without the assistance of medical