Authors: Dhesingh Ravi Shankaran Toshikazu Kawaguchi Sook Jin Kim Kiyoshi Matsumoto Kiyoshi Toko Norio Miura
Publish Date: 2006/08/10
Volume: 386, Issue: 5, Pages: 1313-1320
Abstract
Detection of TNT is an important environmental and security concern all over the world We herein report the performance and comparison of four immunoassays for rapid and labelfree detection of 246trinitrotoluene TNT based on surface plasmon resonance SPR The immunosensor surface was constructed by immobilization of a homemade 246trinitrophenyl–keyhole limpet hemocyanin TNPh–KLH conjugate onto an SPR gold surface by simple physical adsorption within 10 min The immunoreaction of the TNPh–KLH conjugate with four different antibodies namely monoclonal antiTNT antibody MTNT Ab monoclonal antitrinitrophenol antibody MTNP Ab polyclonal antitrinitrophenyl antibody PTNPh Ab and polyclonal antiTNP antibody PTNP Ab was studied by SPR The principle of indirect competitive immunoreaction was employed for quantification of TNT Among the four antibodies the PTNPh Ab prepared by our group showed highest sensitivity with a detection limit of 0002 ng/mL 2 ppt TNT The lowest detection limits observed with other commercial antibodies were 0008 ng/mL 8 ppt 025 ng/mL 250 ppt and 40 ng/mL ppb for MTNT Ab PTNP Ab and MTNP Ab respectively in the similar assay format The concentration of the conjugate and the antibodies were optimized for use in the immunoassay The response time for an immunoreaction was 36 s and a single immunocycle could be done within 2 min including the sensor surface regeneration using pepsin solution In addition to the quantification of TNT all immunoassays were evaluated for robustness and crossreactivity towards several TNT analogsWe gratefully acknowledge Japan Science and Technology Agency for partial funding of this work One of the authors D Ravi Shankaran would like to acknowledge Japan Society for the Promotion of Science JSPS for providing a postdoctoral fellowship
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