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Specificity of polyclonal antibody-based magnetostrictive biosensors

Jia-Jia Hu, R.Guntupalli, Bryan A.Chin, Jing Hu

Magnetoelastic (ME) biosensors were developed by immobilizing polyclonal antibody using Langmuir-Blodgett (LB) technique onto a magnetostrictive platform, which can offer wireless and remote detecting, a unique advantage over conventional sensor platforms. Due to the magnetoelastic nature of the amorphous magnetostrictive alloy, the sensor exhibits a physical resonance when it undergoes a time-varying magnetic field, a shift in resonance frequency occurs when its mass changes due to bacteria binding, and the bound bacterial cells were visibly confirmed by scanning electron microscopy (SEM) micrographs, then the density of bacteria bound on the biosensor was calculated. The specificity to detect different kinds of bacteria, including Salmonella species and non- Salmonella species was studied. The results show that the prepared polyclonal antibodybased biosensor shows excellent specificity to detect bacteria of Salmonella species, and especially prefers to bind Salmonella typhimurium, almost zero affinity for non- Salmonella species of Listeria monocytogenes.