ABSTRACT
Microfluidics is promising for point-of-care detection in healthcare applications initially involving silicon-based material in microelectromechanical systems (MEMS) technology in combination with materials such as PDMS and glass, resulting in complex fabrication processes. Flexible microfluidic biosensor technology based on paper as a substrate is being pursued to overcome fabrication complexities and making point-of-care detection cost-effective and for one-time usage to avoid disease infection. Paper as a substrate is helpful to mitigate existing rigid wastes and unavoidable pollution. Parameters of paper quality suitable for microfluidic action are different from traditional cellulose paper applications. In microfluidics, realizing microchannels for a controlled flow of liquid in a pre-determined direction is a prime requisite, which is achieved by introducing selective hydrophobicity in the hydrophilic environment employing relevant technology. Microstructures of paper and their role in microfluidic action and related technology of realizing microchannels are presented in this chapter. Traditionally, paper has been used for manual writings using inks initially and later with advanced technology of printing for record-keeping. Print quality paper is composed of cellulose and is hydrophilic in nature, and its fibrous structure offers isotropic microchannels for capillary action making microfluidics possible. Paper-based flexible microfluidic technology provides a versatile and cost-effective technological platform for next-generation smart systems.
