Characterization of the flow rate on lab-on-a-disc by a low-powered electrolysis pump for wireless-controlled automation of bioanalytical assays

Abstract

Pumping mechanism in centrifugal microfluidic platforms enable liquid delivery against the unidirectional centrifugal force. Electrolysis pumping is a method that relies on pneumatic pressure generated by the accumulation of oxygen and hydrogen to propel liquids towards the CD center. Previously, we presented a wirelessly controlled electrolysis (EL) pump with 3D structure to optimize CD space for multiple pump integration. However, the performance of EL pump for low power ranges, and its usage in a real-life application have not been yet demonstrated. In this study, we present the analysis of the EL pump performance over a rotational speed range from 600 to 1500 RPM at low electrical power rates of up to 45 mW. The liquid pumping rate was studied theoretically and compared with the experimental data. The EL pump presented a consistent flow rate of 70–410 nL/s, showing a robust and predictable actuation for small volume delivery. As a first real-life application, we presented the isolation of a specific volume of supernatant liquid after sedimentation of yeast. A theoretical model predicted a period time of 135 s needed to pump 40 µL of supernatant. In our experimental set-up we observed a volume of 43 µL moved in the same amount of time which makes a very good match with the predicted value. As a second real-time application, we presented a centrifugal microfluidic design with multiple wirelessly controlled EL pumps to automate a peptide microarray-based immunoassay for the detection of influenza hemagglutinin antibody.