Fast and simple fabrication procedure of whole-glass microfluidic devices with metal electrodes

[Display omitted] •Fabrication procedure of whole-glass microfluidic chip with metal electrodes was developed.•Sodium silicate as an intermediate layer between the two glass substrates is used.•The functionality of the electrode array was confirmed by EIS. We developed a new process for fabrication of whole-glass microfluidic chips with integrated metal electrode arrays. Our process is based on a novel technique that enables reliable bonding of two glass substrates, one with a microfluidic channel and the other with an electrode array. The technique uses sodium silicate as an intermediate layer between the two glass substrates; this layer provides very tight bonding while preserving full functionality of the metal electrodes. Functionality of the electrode array was confirmed by impedance spectroscopy measurements of KCl solutions with different concentrations. To confirm the quality of bonding, we used a solution of fluorescein as a tracer of any poorly bonded areas. Our results showed that there was no fluorescein leakage out of the microfluidic channel and that the electrodes were free of sodium silicate where desired. Our method can be applied to fast and cost-effective prototyping of whole-glass microfluidic chips with integrated electrode arrays.