Flexible and Easy-to-fabricate Electrochemical Sensors Integrating an Absorption Layer with Paper Microfluidic

Electrochemical sensors can provide numerous health information while analyzing ions in bio-fluids. Ion selective electrodes (ISEs) have become ideal sensing devices for measuring cation and anion concentrations in aqueous samples. In the scenario for human bio-fluidics detection, substrate should be flexible in comply with body and hydrophilic to enrich fluidics in natural perspiration analysis in a possible way. Here graphite paper ISE combined with paper microfluidic is presented to meet both requirements. The ion-to-electron transducer of the ISE electrodes was achieved by subjecting PEDOT: PSS and carbon nanotubes solutions on the top of conducting layer (Ag, Graphite paper) accordingly, through which potential drift can be minimized. A no-mask process including paper-cutting, wax-printing and cast-dropping, has also been introduced to realize the easy fabrication for lab experiments and future development.