title: Surface plasmon resonance immunosensor for highly sensitive detection of 2,4,6-trinitrotoluene.
abstract: We have examined the sensing characteristics of a surface plasmon resonance (SPR) immunoassay for the detection of 2,4,6-trinitrotoluene (TNT) using an immunoreaction between 2,4,6-trinitrophenol-ovalbumin (TNP-OVA) conjugate and anti-2,4,6-trinitrophenol antibody (anti-TNP antibody). TNP-OVA conjugate was attached to a SPR-gold sensing surface by means of physical immobilization, which undergoes binding interaction with anti-TNP antibody. Both the immobilization and binding processes were studied from a change in the SPR-resonance angle. The quantification of TNT is based on the principle of indirect competitive immunoassay, in which the immunoreaction between the TNP-OVA conjugate and anti-TNP antibody was inhibited in the presence of free TNT in solution. The decrease in the resonance angle shift is proportional to an increase in concentration of TNT used for incubation. The immunoassay exhibited excellent sensitivity for the detection of TNT in the concentration range from 0.09 to 1000 ng/ml with good stability and reproducibility. The immunosensor developed could detect TNT as low as 0.09 ng/ml, within a response time of approximately 22 min. The sensor surface was regenerated by a brief flow of pepsin solution, which disrupts the antigen-antibody complex without destroying the conjugate biofilm. Cross-reactivity of the SPR sensor to some structurally related nitroaromatic derivative and the detection of TNT in the presence of these nitroaromatic compounds were investigated. The cross-reactivity of the SPR sensor to 2,4-dinitrotoluene (2,4-DNT), 1,3-dinitrobenzene (1,3-DNB), 2-amino-4,6-dinitrotoluene (2A-4,6-DNT) and 4-amino-2,6-dinitrotoluene (4A-2,6-DNT) were very low (< or =1.1%). The analytical characteristics of the proposed immunosensor are highly promising for the development of new field-portable sensors for on-site detection of landmines.
authors.affiliation: Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-shi, Fukuoka 816-8580, Japan. dravishankaran@hotmail.com
authors.forename: Dhesingh Ravi
authors.initials: DR
authors.lastname: Shankaran
authors.forename: K Vengatajalabathy
authors.initials: KV
authors.lastname: Gobi
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Sakai
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Toko
authors.forename: Norio
authors.initials: N
authors.lastname: Miura
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004784:Environmental Monitoring / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D010047:Ovalbumin / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods; D014159:Transducers; D014303:Trinitrotoluene / Q000032:analysis* / Q000276:immunology
chemical_list: D014303:Trinitrotoluene; D010047:Ovalbumin