Pesticide immunosensors regeneration

The first SPR immunosensor for detection of pesticides was developed by Mimmni et al. [22] in the early 1990s. They used an SPR sensor developed by Biacore AB, Sweden, with the atrazine derivative bound to dextran matrix on the sensor chip. The detection of atrazine was performed using the inhibition assay and monoclonal antibodies. The sensor response was subsequently amplified by secondary antibody, which was bound to the antibody captured by the atrazine derivative (sandwich assay, see Chap. 7 in this volume [54]). This biosensor was demonstrated to measure atrazine in distilled and tap water within the range 0.05-1 ng mL in 15 min and exhibited relatively low crossreactivity with simazine and tetrabutyl atrazine (20%). The sensor surface was regenerated with 100 mM sodium hydroxide in 20% acetonitrile. 

Another widely used pesticide, 2-4 dichlorophenoxyacetic acid (2,4-D), was detected with an SPR immunosensor by Gobi et al. [25]. They used inhibition assay and a sensor chip on which the conjugate of BSA and 2,4-D derivative was physisorbed. The detection was performed with monoclonal antibodies in phosphate buffer saline (PBS) using a commercial SPR-20 instrument (from DKK-TOA, Japan). A detection range of 0.5ngmL to 1 p,gmL and a detection time of 20 min were achieved. Regeneration of the sensor for up to 20 detection cycles was performed using pepsin (10 p.g mL ). 

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