- About Us
- Career Center
- Nano-Social Network
- Nano Consulting
- My Account
|Porous photonic crystal microsensor particles on the ends of optical fibers can detect organic pollutants. Photo by Brian King, UCSD Chemistry and Biochemistry.|
A new kind of sensor could warn emergency workers when carbon filters in the respirators they wear to avoid inhaling toxic fumes have become dangerously saturated.
In a recent issue of the journal Advanced Materials, a team of researchers from the University of California, San Diego and Tyco Electronics describe how they made the carbon nanostructures and demonstrate their potential use as microsensors for volatile organic compounds.
First responders protect themselves from such vapors, whose composition is often unknown, by breathing through a canister filled with activated charcoal - a gas mask.
Airborne toxins stick to the carbon in the filter, trapping the dangerous materials.
As the filters become saturated, chemicals will begin to pass through. The respirator can then do more harm than good by providing an illusion of safety. But there is no easy way to determine when the filter is spent. Current safety protocols base the timing of filter changes on how long the user has worn the mask.
"The new sensors would provide a more accurate reading of how much material the carbon in the filters has actually absorbed," said team leader Michael Sailor, professor of chemistry and biochemistry and bioengineering at UC San Diego. "Because these carbon nanofibers have the same chemical properties as the activated charcoal used in respirators, they have a similar ability to absorb organic pollutants."
Sailor's team assembled the nanofibers into repeating structures called photonic crystals that reflect specific wavelengths, or colors, of light. The wing scales of the Morpho butterfly, which give the insect its brilliant iridescent coloration, are natural examples of this kind of structure.
The sensors are an iridescent color too, rather than black like ordinary carbon. That color changes when the fibers absorb toxins - a visible indication of their capacity for absorbing additional chemicals.
The agency that certifies respirators in the U.S., the National Institute of Occupational Safety and Health, has long sought such a sensor but the design requirements for a tiny, sensitive, inexpensive device that requires little power, have proved difficult to meet.
The materials that the team fabricated are very thin - less than half the width of a human hair. Sailor's group has previously placed similar photonic sensors on the tips of optical fibers less than a millimeter across and shown that they can be inserted into respirator cartridges. And the crystals are sensitive enough to detect chemicals such as toluene at concentrations as low as one part per million.
Ting Gao, a senior researcher at the Polymers, Ceramics, and Technical Services Laboratories of Tyco Electronics in Menlo Park, California and Timothy L. Kelly, a NSERC post-doctoral fellow at UC San Diego co-authored the paper. The National Science Foundation, the Department of Homeland Security, the Natural Sciences and Engineering Research Council of Canada, and TYCO Electronics provided funding for the work.
For more information, please click here
Copyright © UCSDIf you have a comment, please Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
|Related News Press|
News and information
Animal study shows flexible, dissolvable silicon device promising for brain monitoring: Other applications include post-operative observation for vascular, cardiac, and orthopaedic procedures, finds Penn study May 5th, 2016
Electrically Conductive Graphene Ink Enables Printing of Biosensors April 23rd, 2016
Highlights from the Graphene Flagship April 22nd, 2016
The intermediates in a chemical reaction photographed 'red-handed' Researchers at the UPV/EHU-University of the Basque Country have for the first time succeeded in imaging all the steps in a complex organic reaction and have resolved the mechanisms that explain it May 4th, 2016
Cooling graphene-based film close to pilot-scale production April 30th, 2016