Concept of the sensor (via MIT & Wiley Online Library)
The list of applications for carbon nanotubes seems to keep growing and growing. Scientists at MIT have found a way to give these nanotubes the capability of detecting gasses that are present during the process of ripening and rotting of fruits and vegetables.
These sensors consist of tens of thousands of carbon nanotubes that have been treated with copper atoms and polystyrene. Ethylene, a gas present during the ripening process, sticks to the copper and thus slows the flow of electrons through the carbon nanotubes. The higher the ethylene content in the air, the slower the electron flow is, and this can be correlated to determine the stage of ripening or rotting. Combining the sensor with an RFID chip allows for real time monitoring of produce. The sensor detects 0.5 parts per billion of ethylene in the air which makes it extremely sensitive. The sensor itself can be manufactured for only 25 cents, while the addition of an RFID chip increased the price to only $1 total per unit.
These sensors could change how produce is handled in stores like when it is put on clearance. This sensor can also be used to manage plants in new and beneficial ways. According to the USDA, 10% of produce is lost to spoilage annually.
The U.S. Army Office of Research funded the MIT research. The army is hoping this paves the way to more general electrochemical sensors such as mold or bacteria detectors.
A brief collection of Carbon Nano-tube related news: