Fig. 4. Optimization of enrichment time and enrichment cycle number for immunoassays utilizing the hybrid PnP microfluidic device.

Enrichment time refers to the incubation time allowing for the analytes to be adsorbed on paper in a static status between each cycle of pumping through paper. a The relationship between the enrichment time and net brightness difference between the analyte and the negative control. b The relationship between the number of enrichment cycles and net brightness difference between the analyte and the negative control.