Performance enhancement of polyaniline-based polymeric wire biosensor.

We demonstrate here the performance enhancement of polyaniline-based biosensor using screen-printing technology and pulse mode measurement technique. Screen-printed silver electrodes were made on a nitrocellulose membrane and the distance between the two electrodes was approximately 550 microm. Resistance of the electrodes had an average of 1.4 Omega with a standard deviation of +/-0.4 Omega. The surface of nitrocellulose membrane was modified by glutaraldehyde to immobilize streptavidin. Biotinylated anti-mouse IgG was conjugated with polyaniline-coated magnetic nanoparticles. Formation of polyaniline-coated magnetic nanoparticles was confirmed by a transmission electron microscope image. The polyaniline was used as an electric signal transducer for the monitoring of the biospecific binding event. An electrical response induced by the streptavidin-biotin interaction was measured by pulse mode measurement. This measurement method reduced the resistance caused by interfacial capacitance. Dose-dependent resistance changes were also successfully analyzed by the pulse mode polymeric wire biosensor. Results showed that the pulse mode measurement technique enhanced the performance of the polyaniline-based polymeric wire biosensor by reducing the interfacial effects. This approach could be helpful in samples with high interfering background materials, such as food and clinical specimens.