A collaborative team of scientists from University of Michigan and Jiangnan University in China have developed paper sensors, impregnated with antibodies and carbon nanotubes, that can quickly and precisely detect the presence of toxins in water.
Michael Berger over at Nanowerk reports:
For their sensor, the researchers dip-coated regular filter paper strips with a SWCNT [single-walled carbon nanotube] dispersion and dried it in air; dip-dry cycles were repeated until the desirable electrical parameters of the sensor were obtained. The dispersion was a PSS-water solution with a concentration of 50 mg/mL. To 6 microliters of this solution they added ten mL of antibodies to Microcystin-LR – one of the most common and the most dangerous toxins produced by the cyanobacteria – to obtain an antibody concentration of 10 µg/mL. Under these conditions, the SWCNT/antibody ratio was about 5000:1.
Kotov mentions that the team also tested multi-walled carbon nanotubes in an analogous process but the corresponding MWCNT-paper composites displayed lower stability under current, lower conductivity, and lower overall robustness than SWNT electrodes.
For sensing, the team employed the standard three-electrode electrochemical station to measure changes in electrical properties of the SWCNT-paper strips, which were used as work electrodes.
More from Nanowerk…
Abstract in Nano Letters: Simple, Rapid, Sensitive, and Versatile SWNT-Paper Sensor for Environmental Toxin Detection Competitive with ELISA