Construction and evaluation of a regenerable fluoroimmunochemical-based fibre optic biosensor

Abstract

A microscale fibre optic biosensor that is capable of in situ regeneration is described and characterized. By combining recently developed fibre optic sensing technology with a capillary column reagent delivery system, it is possible to perform a variety of bench-top affinity assay procedures both repetitively and remotely. The configuration of the sensing chamber at the terminus of the fibre is an important design feature. The construction and operation of the sensor is described and the results of evaluations of the sensor using an antibody–antigen system are presented. Affinity assay steps such as the delivery of solid phase affinity reagents, secondary reagents and rinse solutions are demonstrated. Sampling is accomplished by mild aspiration. Relative standard deviations (RSDs) for these steps are all less than 10%. The capability of selectively measuring fluorescently labelled anti-rabbit immunoglobulin G (lgG), in the presence of a similar protein, by utilizing its immunospecific interaction with rabbit lgG immobilized on silica beads is demonstrated, and exhibits an RSD of 6.2%. A near linear calibration graph is presented over a concentration range of between 0.011 (approximately the limit of detection) and 0.11 mg ml^–1.