| Abstract
| - Antibodies to trinitrotoluene (TNT) were encapsulated in optically transparent sol−gelderived 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 usingthe sol−gel immobilized antibodies, a logarithmic decrease in fluorescence signal as a functionof TNT concentration was observed, similar to competitive immunoassays performed insolution. When encapsulated in the sol−gel silica matrix, the antibodies retained their abilityto differentiate between TNT and trinitrobenzene (TNB), an analogue. In displacementimmunoassays, the rate of displacement was dependent upon pore morphology, with agedgels exhibiting faster rates than that of xerogels. The relative stability of antibodies wasbetter for sol−gel encapsulated antibodies than for antibodies immobilized using surfaceattachment. After exposure to HCl, methanol, or 60 °C, the sol−gel immobilized antibodiesexperienced essentially no loss in ability to bind TNT whereas the surface immobilizedantibodies showed as much as 30% loss in ability to bind TNT.
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