Microbead immunoassay with electrochemical detection has been
developed as a sensitive and selective technique for rapid and
small volume analyses. In this assay, applications of
paramagnetic microbeads in a microfluidic system have aided the
automation of all assay steps to enable near-continuous
monitoring. These mobile microbeads can be transported through
microchannels, captured and held at specific points by a magnet.
Hence, by performing immunoassay on microbeads, they can be
dispersed throughout a small sample of water, where they provide
a large surface area to sample volume ratio that enhances the
capture of the target antigen by minimizing diffusional
distances. They can then be collected magnetically and
manipulated to accomplish all the assay steps to determine if
any target was captured. In addition, the microbeads can be
accommodated in small volumes, which reduces the dilution of the
enzyme product in the detection step thus maximizing
sensitivity. Further, electrochemical detection coupled wit