Electrode fabrication using conductive nano-ink and microfluidic technology for bio-applications

Printed electronics technology, which is used to economically prepare printing conductive patterns onto flexible materials, is both fundamental and crucial for the successful integration of electronics with textiles or fluidics. Conductive channels can be prepared using conventional printing technologies and conductive inks. These preparation methods would cost less, and they are convenient for prototyping of microdevices. The use of hydrophilic organic-inorganic hybrid nanoparticles (NPs), dispersed in water, enables the simplification of the electrode preparation process at room temperature. In this study, we developed a transparent breadboard and NP microelectrodes in the microfluidic channel to measure the number of particles. The electrode fabrication in the microfluidic channel can be acquired using conventional laboratory equipment without the need for expensive ultra-vacuum deposition instruments. We integrated the equipment with electrical measurement systems to count cells and/or microparticles. By using a parallel electric-circuit model (diluted case) or Langmuir isotherm model (saturated case), the particle concentration between two NP electrodes can be analyzed by measuring the capacitance of the total circuit. The microfluidic fabrication of electrodes and electrical measurement technologies may be potentially applied to the technology for micro-nano fluidics and bio-applications such as cell counting or ion sensing.