Sandwich immunoassay on a microfluidic chip using patterns of electrostatically self-assembled streptavidin-coated beads

In this paper, we demonstrate a bead-based microfluidic immunoassay using self-assembled streptavidin-coated bead micropatterns. The beads are assembled on the microfluidic channel surface using electrostatic forces between the negatively-charged streptavidin-coated beads and the positively-charged aminosilane micropatterns. The immunoassay is performed in the stop-flow mode and uses mouse IgG diluted in phosphate buffered saline (PBS) solution as the model target antigen. The total immunoassay takes around 30 min and is able to detect mouse IgG antigen down to a concentration of 15 ng/mL by using only 560 nl of analyte volume.