Medical applications of fiberoptic sensors

The key requirements of receptor biomolecules for use in affinity optodes are 1) totally reversible binding, 2) rapid equilibration (on the order of minutes or less), 3) no destruction of the analyte or competing analyte, 4) high differential selectivity (binding constants) for analytes of similar structures, and 5) long-term stability. An obvious first choice for sources of receptors for biosensors is antibodies; these immunoproteins are easily derived for drugs, metabolites, and hormones. However, most of the antibodies selected for immunoassay purposes have very high binding constants for their analytes, which may be the result of very slow dissociation rates. Thus, antibodies to be used in biosensors should be screened for high dissociation rates. Monoclonal antibodies appear to be the most suitable from this point of view.