A new, versatile field immunosensor for environmental pollutants

• Published in: Biosensors & bioelectronics Vol. 21; no. 2; pp. 354 - 364
• Main Authors: Ciumasu, Ioan M., Krämer, Petra M., Weber, Cristina M., Kolb, Gunther, Tiemann, David, Windisch, Stefan, Frese, Ines, Kettrup, Antonius A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2005
• Subjects: Atrazine; Chemiluminescence; Diuron; Flow-injection immunosensor; Isoproturon; Nitroaromatic compounds; Pesticides; TNT; Isoproturon; Pesticides; Diuron; Chemiluminescence; TNT; Flow-injection immunosensor; Nitroaromatic compounds; Atrazine
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2004.10.027

This paper presents a new, versatile, portable miniaturized flow-injection immunosensor which is designed for field analysis. The temperature-controlled field prototype can run for 6 h without external power supply. The bio-recognition element is an analyte-specific antibody immobilized on a gold surface of pyramidal structures inside an exchangeable single-use chip, which hosts also the enzyme-tracer and the sample reservoirs. The competition between the enzyme-tracer and the analyte for the antigen-binding sites of the antibodies yields in the final step a chemiluminescence signal that is inversely proportional to the concentration of analyte in the given range of detection. A proof of principle is shown for nitroaromatics and pesticides. The detection limits (DL; IC 20) reached with the field prototype in the laboratory was below 0.1 μg l −1 for 2,4,6-trinitrotoluene (TNT), and about 0.2 μg l −1 for diuron and atrazine, respectively. Important aspects in this development were the design of the competition between analyte and enzyme-tracer, the unspecific signal due to unspecific binding and/or luminescence background signal, and the flow pattern inside the chip.