Paper-based microfluidic devices: Fabrication, detection, and significant applications in various fields

Paper is the most abundant and inexpensive polymeric structure of cellulose available. Paper has micro-porous capillary-like networks which are responsible for flow of solvents instead of pumps or electronic power, making paper an ideally usable tool. Microfluidic paper-based analytical devices use fabricated paper devices on which hydrophilic zones are formed within hydrophobic barriers. Hydrophilic zones act as regions for actual analytical purposes, whereas hydrophobic zones act to demarcate separate zones from one another. Clinically, these devices have been proved to be excellent point-of-care-devices in diagnosis which can bypass use of costly and time-consuming laboratory techniques. In the presented review, the basic principles and components involved in the design of paper-based devices were then summarised in understandable manner. Further, various applications in different fields were also compiled in the form of text under different sections and tables. Paper-based analytical devices may serve as an excellent tool in variety of analytical works as these techniques are simple, rapid, economic, and require less human power or trainings. They have prominent applications in analysis of biological fluids, drugs/metabolites, food stuffs, colorants, biomarkers, and several other fields.