Electrochemical paper-based analytical devices (ePADs) toward biosensing: recent advances and challenges in bioanalysis

Paper has been used for more than a century in analytical and bioanalytical devices, owing to its low cost. Based on its biodegradability, biocompatibility, worldwide abundance, chemical, stability and three-dimensional fibrous structure, paper is one of the most widely used substrates for the construction of low-cost disposable devices and sensing platforms. Electrochemical paper-based devices (ePADs) have attracted widespread attention in biosensing due to their benefits in biomedical analysis. For analytical measurements ranging from clinical diagnostics to environmental biosensing, ePADs are simple, portable, inexpensive, rapid, flexible, and easy-to-use analytical tools for point-of-care diagnosis. This review surveys the recent advances in ePAD development in biosensing. Also, fabrication techniques and examples of applications in immunosensing, aptasensing and genosensing were discussed. In addition, the advantages and limitations of ePADs in biosensing are investigated. Finally, the challenges of these biosensors are discussed.