Distance versus Capillary Flow Dynamics‐Based Detection Methods on a Microfluidic Paper‐Based Analytical Device (μPAD)

• Published in: Chemistry : a European journal Vol. 25; no. 57; pp. 13070 - 13077
• Main Authors: Chung, Soo, Jennings, Christian M., Yoon, Jeong‐Yeol
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11-10-2019
• Subjects: analytical methods; Capillary flow; capillary flow dynamics; Chemistry; Colorimetry; Cost analysis; Electrochemical analysis; Electrochemistry; Fluid dynamics; Fluorescence; Liquid flow; machine learning; Microfluidics; Optical pumping; Organic chemistry; Perturbation; point-of-care diagnostics; Portable equipment; point-of-care diagnostics; capillary flow dynamics; machine learning; analytical methods; microfluidics
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201901514

In recent years, there has been high interest in paper‐based microfluidic sensors or microfluidic paper‐based analytical devices (μPADs) towards low‐cost, portable, and easy‐to‐use sensing for chemical and biological targets. μPAD allows spontaneous liquid flow without any external or internal pumping, as well as an innate filtration capability. Although both optical (colorimetric and fluorescent) and electrochemical detection have been demonstrated on μPADs, several limitations still remain, such as the need for additional equipment, vulnerability to ambient lighting perturbation, and inferior sensitivity. Herein, alternative detection methods on μPADs are reviewed to resolve these issues, including relatively well studied distance‐based measurements and the newer capillary flow dynamics‐based method. Detection principles, assay performance, strengths, and weaknesses are explained for these methods, along with their potential future applications towards point‐of‐care medical diagnostics and other field‐based applications.
Long and short of it: Alternative detection methods have emerged to resolve the issues of optical and electrochemical detection methods on microfluidic paper‐based analytical devices (see figure). Distance‐based measurements and capillary flow dynamics‐based measurements are two methods compared herein.