Fabrication for paper-based microfluidic analytical devices and saliva analysis application

Paper-based microfluidic analytical devices (μPADs) have shown great potential in the field of analysis due to their advantages of rapid analysis, environmental friendliness and the ability to realize the flow of fluid without external power. Saliva is an emerging biofluid which is used in diseases diagnostic and screening for the easy collection and the reflection of the physiological state. This review focuses on the fabrication methods for two-dimensional (2D) and three-dimensional (3D) μPADs and their applications on the saliva analysis. In the first part, the flow mechanism in μPADs is discussed. The second part mainly introduces the fabrication methods for the μPADs and compares the different methods. The third part presents the application of μPADs in the detection of biomarkers such as nitrite, glucose, and thiocyanate in saliva. Finally, the research directions of saliva analysis are discussed in the conclusion. There have been a lot of researches on μPADs, but the fabrication methods and applications need to be further studied to meet the commercial needs.