July 2008

Xendo recently purchased a Sector Imager 2400 A (Meso Scale Discovery), allowing the performance of electrochemiluminescence (ECL) assays. ECL is the chemiluminescent reaction of components that are generated electrochemically at the surface of an electrode. The instrument offers a sensitive method for immunoassays in microplates with one to ten carbon electrode arrays per well. As each electrode represents an independent assay, this format enables multiplex assays in which up to ten different analytes in one sample can be measured in each well.
A ruthenium containing SULFO-TAGTM label is covalently linked to the detection antibody. Only labels near the electrode (i.e. bound to the electrode by antibody-protein interactions) are excited and detected. This gives the potential for non-wash assays.
ECL offers, compared to traditional ELISA methods, an increased sensitivity, large dynamic range, better free drug tolerance, reduced matrix interference and the ability to measure low affinity antibodies. ECL assays can be used for immunogenicity determination, PK analysis and biomarker analysis.