September 14, 2006 – Researchers at Arizona State U. and Motorola Labs have developed a method for applying peptides to single-walled carbon nanotubes in field-effect transistors, creating sensors that can identify the presence of specific metals in water or air.

The peptides, made of ~20 or so amino acids, are selective to specific compounds — e.g., one peptide has been developed to detect nickel and blind to all other heavy metal ions (e.g. copper, lead, or zinc) passing over the carbon nanotubes. Changing the sequence of the amino acids making up each peptide allows researches to “tune” them to recognize different compounds.

The sensors were shown to detect the presence of heavy metal ions in water down to parts-per-trillion levels, but the platform can be applied to other areas, such as sensing toxic chemicals in the air, or as biosensors in medical applications, according to researcher Nongjian Tao, an electrical engineering professor at Arizona State U. Erica Forzani, an ASU assistant research professor in electrical engineering, noted that “with a very simple device that does not require sophisticated electronic circuitry, you can detect very low concentrations of analytes.”

The research will continue to investigate the use of the sensors on biological molecules, such as RNA sequence detection.