Continuous-flow immunosensor for detection of explosives

Abstract

A continuous-flow immunosensor for detection of trinitrotoluene (TNT) in aqueous solution is de-scribed. The sensor utilizes an immobilized monoclonal antibody specific for TNT and saturated with fluorescein-labeled antigen. When introduced into the flow stream through the column, samples containing unlabeled antigen displace the bound labeled antigen. The displaced labeled antigen is detected downstream using a fluorometer. The displacement of labeled antigen is directly proportional to the concentration of unlabeled antigen applied to the column over a range of 20 to 1200 ng/mL (ppb). The sensitivity is increased when solvents (ethanol or 2-propanol) are included in the flow buffer at concentrations up to 25% (v/v). By use of a cyclone air sampler and a TNT vapor generator, TNT could be detected in collected samples. The flow immunosensor provides the means to detect trace levels of TNT with high specificity in times of less than 1 min. Such qualities make the flow immunosensor a promising low-cost alternative to explosive detection devices currently available to transportation and security industries.

Multichannel homogeneous immunoassay for detection of 2,4,6‐trinitrotoluene (TNT) using a microfabricated capillary array electrophoresis chip

“…The trinitrobenzene (TNB) moiety was labeled by coupling FC to TNBS according to a previous procedure [29]. FC solution was prepared by dissolving 6.4 mg of FC in 5 mL borate buffer (0.17 M borax, 0.12 M NaCl, pH 8.7) and TNBS solution was prepared by mixing 0.05 mL of 5% TNBS with 0.45 mL of the same borate buffer.…”

“…The majority of the sensitivity difference is probably due to the different buffers and pH conditions used in the two studies. The immunoassay in our single capillary study was performed at a more optimal pH (10 mM phosphate buffer, pH 7.4 ) [29] than that of the present study (0.86 TAE, pH 8.2).…”

Imprinted Au‐Nanoparticle Composites for the Ultrasensitive Surface Plasmon Resonance Detection of Hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX)

“…Fluorescent organic polymers, which are quenched by nitroaromatic explosives, [3,4] luminescent polysilole nanoparticles (NPs), [5,6] or fluorescent silicon NPs quenched by nitroaromatic vapors enabled the development of optical sensors. The electrochemical activity of the nitro groups of TNT provided the basis for developing voltammetric sensors for this explosive, [7,8] and recently, a composite of Au NPs linked to electrodes enabled a sensitive electrochemical detection of TNT.[9] Also, different sensing matrices, such as cyclodextrin polymers, [10] carbowax, [11] or silicon polymers, [12] were used for TNT analysis by surface acoustic wave devices, and the aggregation of functionalized Au NPs in the presence of TNT was used to develop an optical sensor for the explosive.[13] Similarly, antibody-based optical [14][15][16] or microgravimetric quartz-crystal-microbalance [17] biosensors for TNT were developed. Different optical [18,19] or voltammetric [20] sensors for RDX were also reported.…”

Peer Reviewed: Chromatographic Immunoassays

“…However, the technique is highly dependent on flow rate and the labeled analogue's rate of dissociation. When using high-affinity antibodies and slowly dissociating analogues, this approach tends to produce broad peaks (3,(18)(19)(20).…”