LAUSR

We have previously reported a novel approach to implementing multiplex ELISA in connected microchannels by exploiting the slow diffusion of the enzyme reaction product across the different assay segments. This work builds on that report by implementing the noted assay in segments arranged along the circumference of a circular channel layout to reduce the footprint size and sample volume requirement. Using the current design, a 5-plex cytokine ELISA was demonstrated in a 1.5 cm × 1.5 cm region which corresponded to a reduction in the footprint area by about a factor of three compared to that reported in our previous study. Additionally, the selective coating of our assay segments with the target molecules was realized in this work using electroosmosis instead of hydrodynamic flow as was the case in the previous report. This aspect of our experimental design is particularly significant as it permits the use of cross-sectional channel dimensions significantly shorter than those employed in the current work. Moreover, the use of an electric field for coating purposes enables the integration of functionalities such as electrokinetic pre-concentration of analyte molecules during the sample incubation period which can further enhance the capabilities of our assay method. This article is protected by copyright. All rights reserved.