Microfluidics and materials for smart water monitoring: A review

Abstract

Water quality monitoring of drinking, waste, continental and seawaters is of great importance to ensure safety and wellbeing for humans, fauna and flora. Researchers are developing robust water monitoring microfluidic devices but, the delivery of a cost-effective, commercially available platform has not been achieved yet. Conventional water monitoring is mainly based on laboratory instruments or on sophisticated and expensive handheld probes for on-site analysis, both requiring trained personnel and being time-consuming. As an alternative, microfluidics has emerged as a powerful tool with the capacity to displace conventional analytical systems. Nevertheless, microfluidic devices largely use conventional pumps and valves for operation, and electronics for sensing, that increment the dimensions and costs of the final platforms, diminishing their commercialization perspectives. In this review, we critically analyze the characteristics of conventional microfluidic devices for water monitoring, focusing on different water matrices (drinking, waste, continental and seawaters), towards their application in potential commercial products. Moreover, we introduce the revolutionary concept of using functional materials such as hydrogels, poly(ionic liquid) hydrogels and ionogels as alternatives to conventional fluidic handling and sensing tools for water monitoring in microfluidic devices.