Sol−Gel Encapsulated Anti-Trinitrotoluene Antibodies in Immunoassays for TNT

Abstract

Antibodies to trinitrotoluene (TNT) were encapsulated in optically transparent sol-gel derived silica glasses and retained their ability to bind TNT. Both competitive and displacement immunoassays were successfully performed using sol-gel immobilized antibodies. TNT concentrations on the order of ppm were detected. In competitive immunoassays using the sol-gel immobilized antibodies, a logarithmic decrease in fluorescence signal as a function of TNT concentration was observed, similar to competitive immunoassays performed in solution. When encapsulated in the sol-gel silica matrix, the antibodies retained their ability to differentiate between TNT and trinitrobenzene (TNB), an analogue. In displacement immunoassays, the rate of displacement was dependent upon pore morphology, with aged gels exhibiting faster rates than that of xerogels. The relative stability of antibodies was better for sol-gel encapsulated antibodies than for antibodies immobilized using surface attachment. After exposure to HCl, methanol, or 60°C, the sol-gel immobilized antibodies experienced essentially no loss in ability to bind TNT whereas the surface immobilized antibodies showed as much as 30% loss in ability to bind TNT.

Bioactive Sol‐Gel Hybrids

“…Anti-TNT antibodies, trapped within optically transparent sol-gel glasses, retain their ability to bind TNT. Immunoassays, performed with a fluorescent probe, were able to detect traces of the order of ppm and even to differentiate between TNT and TNB (trinitrobenzene) [74]. Antibodies have also been used for electrochemical immunosensors.…”

Surface plasmon resonance for detecting clenbuterol: Influence of monolayer structure

“…In order to add high selectivity, biochemical recognition elements, such as antibodies, enzymes, proteins, DNA and cells are immobilized on the solid surface of the SPR sensor [7][8][9][10]. Biochemical recognition elements can be immobilized by physical adsorption [11], by embedding in polymers or membranes [12,13], by trapping in solgels [14,15], and by using functionalized alkanethiol or functionalized alkylsilane self-assembled monolayer (SAM) [16,17]. Each immobilization approach has advantages.…”

Analysis of aqueous 2,4,6-trinitrotoluene (TNT) using a fluorescent displacement immunoassay

“…On-site analysis methods can be used to assess the nature and extent of contamination as well as to monitor remediation progress. Current on-site methods often involve multiple steps and require between 20 min and 2 h [1,2,3,4,5,6,7]. More rapid methods for dissolved TNT analysis exist, such as continuous flow immunoassays, which have been integrated into field-portable units [8].…”