Fluorescence ELISA versus electrochemical ELISA


At Zimmer and Peacock, we are passionate about ELISA assays, in a recent correspondence with a collaborator our scientist debated the pros and cons of fluorescent ELISA assays versus electrochemical assays, which we have summarized below.


‘…we can indeed perform most bioanalyses with at least the same sensitivity as an established optically-based ELISA or other binding bioassay. I don’t see anything special about the protein ELISA kits that would preclude using a biosensor.

A biosensor is manufactured by binding a suitable antibody to the gold electrode surface. The surface is coated with a self-assembled monolayer, after the coating we bind the appropriate antibody. This is called “activation.” The sample can be processed in a similar mode as with any microplate assay.  Most fluorescent dyes are electrochemically active so it is an easy translation from a fluorescence assay to a biosensor. However, we will usually recommend horseradish peroxidase or ferrocene to improve performance. Electrochemical methods require 1/100th to 1/1000th the power requirements that a fluorescence-based assay requires. This means that we can easily design and manufacture very small test rigs and POC devices.

There may be reasons not to use a biosensor, however sensitivity is not one of these reasons. Biosensors can be printed and packaged in very large quantities at a very low cost. A POC device may be especially suitable in regions of the world where laboratory facilities are overworked or scarce…’