The longevity of polyclonal antibodies to Salmonella typhimurium was investigated by studying the effect of temperature on the binding activity to Salmonella typhimurium using a magnetostrictive platform. Antibodies were immobilized using the Langmuir-Blodgett (LB) technique. Then sensors were stored at temperatures of 25°C (room temperature), 45°C and 65°C, respectively, and then the ability of these sensors to detect S. typhimurium was tested at a predetermined schedule. Changes in the fundamental resonance frequency of sensors after exposure to 1 mL of 1×109 cfu/mL of S. typhimurium were recorded over the testing period. The shift in resonance frequency was attributed to the binding of bacteria to antibody immobilized sensor, which was confirmed by Scanning Electron Microscopy (SEM) micrographs. The results showed that at each temperature, the binding ability of the antibody to S. typhimurium decreased gradually over the testing period, and the higher the temperature, the lower the longevity of the polyclonal antibody. The longevity of polyclonal antibody on the magnetostrictive sensor platform was about 30, 8 and 5 days at room temperature (25°C), 45°C and 65°C, respectively.
Keywords: Magnetostrictive, biosensor, polyclonal antibody, Salmonella typhimurium, langmuir-blodgett, longevity, Langmuir-Blodgett (LB), magnetostrictive resonance, longitudinal vibrations, Monolayer Deposition, vibrations, Long-Term Stability Tests, magnetostrictive sensor, suspension, Teflon barrier