Synthesis of a nano electro-magnetic polymer and its application in a DCT biosensor Sudeshna Pal, Emma B. Hummel and Evangelyn C. Alocilja

摘要

A nano electro-magnetic conductive polyaniline was synthesized for application in a direct-charge transfer biosensor for the detection of Bacillus species. The polymer was synthesized in the presence of ?-Fe_2O_3 nanoparticles with a monomer to ?-Fe_2O_3 nanoparticle ratio of 1:0.4 and had diameter between 50 and 200 nm. The room temperature hysteresis measurements showed that the magnetic polymer had a saturation magnetization value of 43.0 emu/g and approached super paramagnetic behavior. The synthesized nanomagnetic polyaniline was coated with anti Bacillus cereus antibodies and used for separation of the target antigens by applying a magnetic field which was followed by its application into a direct charge transfer (DCT) biosensor. The detection was based on the capillary flow of the nanomagnetic polymer-antigen conjugates which enabled a direct charge transfer in the capture membrane region of the biosensor. Signal generation and data recording was completed in 6 min in a reagentless process. The sensitivity of detection of the biosensor was found to be 10~1 CFU/ml. This easy to use, portable reagent-less biosensor has the potential to serve as a rapid detection tool for countering bioterrorism agents.