Fusible alloy ‘in-contact’ microelectrodes: a rapid and economic microfabrication alternative for microfluidic impedance cytometry
Microfluidic impedance cytometry (MIC) provides a non-optical and label-free method for single cell analysis. However, the cleanroom intensive infrastructure required for MIC electrode fabrication limits its implementation. As an alternate technique that enables rapid prototyping, we fabricated Fields metal in-contact (icFM) coplanar microelectrodes in multilayer elastomer devices with a single photolithography step and characterised them for microfluidic impedance cytometry. Our icFM microelectrodes matched performance of the conventional platinum electrodes in the detection of single human erythrocytes and water-in-oil droplets in a feedback-controlled suction-flow MIC setup. Finally, to facilitate droplet based single cell analysis, we demonstrate detection and quantification of single erythrocytes entrapped in water-in-oil droplets.