Direct detection of low-concentration NO in physiological solutions by a new GaAs-based sensor.
Nitric oxide (NO) acts as a signal molecule in the nervous system, as a defense against infections, as a regulator of blood pressure, and as a gate keeper of blood flow to different organs. In vivo, it is thought to have a lifetime of a few seconds. Therefore, its direct detection at low concentrations is difficult. We report on a new type of hybrid, organic-semiconductor, electronic sensor that makes detection of nitric oxide in physiological solution possible. The mode of action of the device is described to explain how its electrical resistivity changes as a result of NO binding to a layer of native hemin molecules. These molecules are self-assembled on a GaAs surface to which they are attached through a carboxylate binding group. The new sensor provides a fast and simple method for directly detecting NO at concentrations down to 1 microM in physiological aqueous (pH=7.4) solution at room temperature.
Wu
D G
DG
Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel.
Cahen
D
D
Graf
P
P
Naaman
R
R
Nitzan
A
A
Shvarts
D
D
D000465:Algorithms; D000818:Animals; D001151:Arsenic; D015374:Biosensing Techniques; D001921:Brain / Q000378:metabolism; D002264:Carboxylic Acids / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation; D005708:Gallium; D006427:Hemin / Q000737:chemistry*; D007536:Isomerism; D008665:Metalloporphyrins / Q000737:chemistry; D008958:Models, Molecular; D009569:Nitric Oxide / Q000032:analysis*; D051381:Rats; D012666:Semiconductors
D002264:Carboxylic Acids; D008665:Metalloporphyrins; D009569:Nitric Oxide; D006427:Hemin; D005708:Gallium; D001151:Arsenic