An amperometric immunosensor based on carbon nanotube embedded conducting polymer

An amperometric immunosensor based on a multiwall carbon nanotubes (MWCNTs) embedded conducting polymer, poly 5, 2\´: 5\´, 2"-terthiophene-3\´-carboxylic acid (pTTCA), was developed and the sensor was applied for the detection of IgG. The presence of MWCNTs could enhance the conductivity of pTTCA polymer film and consequently, the overall performance of the immunosensor developed was also improved. To amplify the sensitivity of the immunosensor, a conventional sandwich type immune-sensing approach was altered by using hydrazine with co-modified MWCNTs. Hydrazine was used as a multi-label strategy for the detection of amperometric signal and showed a good catalytic property to the reduction of hydrogen peroxide. The physical and surface characteristics were studied for each modification step by scanning electron microscopy (SEM). A calibration curve was constructed and showed a dynamic linear range from 1.0 ng/mL to 5.0 ng/mL with the detection limit of 0.087 ng/mL.