Surface plasmon resonance based pesticide assay on a renewable biosensing surface using the reversible concanavalin A monosaccharide interaction

A competitive immunoassay based on surface plasmon resonance (SPR) for the detection of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) is report ed. The novelty of the assay is based on the regeneration of the chip surfa ce by the reversible interaction between monosaccharide (D-glucose) and lec tin (Concanavalin A). Concanavalin A-2,4-D conjugate was chemically synthes ized, purified and used for binding to the SPR chip modified with covalentl y bound alpha -D-glucose. The interaction between anti-2,4-D antibody and t he surface-bound concanavalin A-2,4-D conjugate was monitored by surface pl asmon resonance and the response was used for the quantification of 2,4-D. The dynamic range of the calibration curve was between 3 and 100 ng/ml. The demonstrated principle of surface regeneration based on the reversible sug ar-lectin interaction may be of more general applicability in immunoassays. (C) 2000 Elsevier Science S.A. All rights reserved.