Another day, another electronic nose. At the National Institute of Standards and Technology researchers are developing a chemical sensor that, in some ways, will mimic olfactory system in animals.
From NIST:

In animals, odorant molecules in the air enter the nostrils and bind with sensory neurons in the nose that convert the chemical interactions into an electrical signal that the brain interprets as a smell. In humans, there are about 350 types of sensory neurons and many copies of each type; dogs and mice have several hundreds more types of sensory neurons than that. Odor recognition proceeds in a step-by-step fashion where the chemical identity is gradually resolved: initial coarse information (e.g. ice-cream is fruit-flavored vs. chocolate) is refined over time to allow finer discrimination (strawberry vs. raspberry). This biological approach inspired the researchers to develop a parallel “divide and conquer” method for use with the electronic nose.
The technology is based on interactions between chemical species and semiconducting sensing materials placed on top of MEMS microheater platforms developed at NIST. (See “NIST ‘Microhotplate’ May Help Search for Extraterrestrial Life,” NIST Tech Beat, Oct., 2001.) The electronic nose employed in the current work is comprised of eight types of sensors in the form of oxide films deposited on the surfaces of 16 microheaters, with two copies of each material. Precise control of the individual heating elements allows the scientists to treat each of them as a collection of “virtual” sensors at 350 temperature increments between 150 to 500 °C, increasing the number of sensors to about 5,600. The combination of the sensing films and the ability to vary the temperature gives the device the analytical equivalent of a snoot full of sensory neurons.
Much like people detect and remember many different smells and use that knowledge to generalize about smells they haven’t encountered before, the electronic nose also needs to be trained to recognize the chemical signatures of different smells before it can deal with unknowns. The great advantage of this system, according to NIST researchers Barani Raman and Steve Semancik, is that you don’t need to expose the array to every chemical it could come in contact with in order to recognize and/or classify them. Breaking the identification process down into simple, small, discrete steps using the most information rich data also avoids ‘noisy’ portions of the sensor response, thereby incorporating robustness against the effects of sensor drift or aging.

Press release: Sniffing Out a Better Chemical Sensor
Medgadget’s electronic nose archives…

At the University of Utah scientists are developing a machine that can identify a number of pathogens in a given sample, using a phenomenon called giant magnetoresistance. The researchers believe the technology can be made both accurate and small enough to resemble a credit card reader.
The following is from the University of Utah statement:

The new testing method makes use of "giant magnetoresistance," or GMR, a phenomenon discovered independently in 1988 by Albert Fert of France and Peter Grünberg of Germany. They shared the 2007 Nobel Prize in Physics for the discovery.
Magnetoresistance is the change in a material’s resistance to electrical current when an external magnetic field is applied to the material. That change usually is not more than 1 percent. But some multilayer materials display a change in resistance of as much as 80 percent. That is giant magnetoresistance.
In the first new study, Porter [Marc Porter, Utah Science, Technology and Research (USTAR) professor of chemistry, chemical engineering and bioengineering], Granger [Michael Granger, USTAR research scientist] and colleagues set the stage for using GMR devices to test medical, environmental or other biological samples.
The prototype reader had four GMR devices: two sensors to detect changes to the magnetic fields of the sample spots, and two "reference elements" to distinguish how magnetic measurements were affected by temperature changes as opposed to the presence of disease indicators in medical samples.
The prototype does not yet look like a credit card reader or card-swipe device. Instead, it is used to "read" a Pyrex glass sample stick about three-quarters-inch long and one-eighth-inch wide. Biological samples can be placed on the sample stick, which then is "scanned much like a credit card reader," Porter says.
In the first study, instead of holding blood or other medical samples, the sample stick had 15 raised spots of iron-nickel "permalloy," a magnetic material that produces a magnetic signature read by GMR sensors.
The study determined how measurements by the GMR sensors – the heart of a future card-swipe device – can be calibrated to account for variations in the size of the permalloy spots, the amount of separation between the sensors and the sample stick, and on the angle of the sample stick as it is scanned by the sensors.
Those factors determine how consistently and accurately a card-swipe device would detect minute amounts of substances associated with diseases.
In the second study, the sample stick’s alloy spots were replaced by the material that would be used on real medical test cards: microscopic spots or "addresses" of gold that were no longer than the smallest known bacterium. The widths were varied to test which size of addresses could be "read" most accurately.
A substance named biotin or vitamin B-7 was bound chemically to the gold spots on the sample stick. Tiny drops of magnetic particles coated with streptavidin – a protein found in eggs – were placed on the gold spots.
"The gold address has no magnetic signature," Granger says. "Once the particles are bound to it, GMR picks up that magnetic signature. It’s a proof of principle."
The experiment was repeated hundreds of times with different concentrations of magnetic particles bound to the biological substance.
"We could detect as few as 800 magnetic particles on an address," Porter says. "We believe that with further development, we can get down to single-particle detection."

Full story: A Card-Swipe for Medical Tests
Image: This green circuit board contains giant magnetoresistance (GMR) sensors (one sensor shown in expanded view) like those that “read” data on a computer hard drive. In a testing method demonstrated by University of Utah scientists, the board would serve as the heart of card-reader that would be used for medical or environmental tests. A credit card-like sample stick containing, blood, saliva, water or other liquids would be swiped through the reader, producing electrical currents that could indicate if any of the samples contained pollutants or substances associated with various diseases. Photo Credit: Michael Granger

Researchers at the Fraunhofer Technology Development Group (TEG) engineered a novel system that allows pressure fluctuation in fluids to be converted into electrical energy by piezoceramic elements. For now, this research will probably go into new sensors to monitor water pipes, but the development of self powered implantable medical devices might be the next step for this technology:

Air compression systems can be found in many manufacturing operations. If a leak occurs anywhere in the system, the air pressure drops and production comes to a halt until the source of failure has been found. Sensors constantly monitor the pressure in order to keep costly fault-related losses to a minimum. At present, these sensors are either battery-driven or connected up by complex technical wiring. This often makes it very difficult or even impossible to install sensors in places that are hard to reach. Fraunhofer researchers from Stuttgart have developed a new technology that enables the production of energy-autonomous and thus low-maintenance sensors. “Our system is eminently suitable for sensors in pneumatic plants, as we can convert the kinetic energy from air or water into electricity,” explains José Israel Ramirez, who is doing research on this topic at the TEG. “The fluidic energy transducer generates electricity in the microwatt or milliwatt range. This is sufficient to supply cyclically operating sensors with enough energy to read out and transmit the relevant data.”
The fluid-electricity conversion takes place in a fixed housing, through which the medium is fed on a course similar to that of blood circulating in the heart. The Coandã effect causes the constant stream of fluid to oscillate. This produces a periodic pressure fluctuation in the feedback branches, which are coupled to piezoceramics. “The piezoceramics convert the fluidic energy into electricity,” says group leader Axel Bindel, summarizing the principle. This fluidic conversion is simple and cost-efficient. “ We have the advantage that both air and water can be used to generate energy. What’s more, we don’t have any movable parts in our system. The structure can be produced in simple processes, and that saves costs.” The new technique can be applied to any system in which a fluid or a gas is guided through a fixed geometry – in supply networks or in medical engineering, for example. “Our objective is to be able to provide currently battery-driven devices, such as water meters, with an autonomous supply of energy in the near future, resulting in completely independent systems,” says Bindel. The TEG researchers will be presenting a prototype of the fluid transducer at the joint Fraunhofer stand at the electronica trade fair.

Full story: The fluid transducer: electricity from gas and water…