Antibody affinities, detection using immunosensors

In essence, this technique allows for the detection of surface binding interactions in real time without the use of labels. Immunosensors that rely on these principles are commercially available from Biacore AB (formerly Pharmacia Biosensor). These are based on the popular BIACORE 3000, BIACORE 2000 and BIACORE probe instruments in conjunction with disposable sensor chips, which may be purchased with affinity capture chemistries in place (e.g. SA5 Sensor Chips with streptavidin bearing surfaces for capture of biotinylated compounds) [92]. These devices incorporate micro-fluidic systems for delivery of reagents required for analysis and are capable of measuring affinities and kinetics of antibody-antigen interactions in addition to analyte concentrations, which can be determined to the picomolar range [93]. 

Furthermore, research efforts described herein, have resulted in at least a ten-fold improvement in the detection of Clostridium botulinum neurotoxin using a fiberoptic immunosensor. Additionally, the increased sensitivity of the assay by using affinity purified polyclonal antibodies as both the immobilized capture antibodies and the fluorescently labeled antibodies suggests that the investigation into additional assay systems may be worthwhile. 

---