July R&D Round Up

E-mail Melanie Martella

This month we've got a clever system that partners drugs containing ingestible sensor chips to a wireless monitor to ensure patient compliance, a new gas sensor chip that can detect many different chemicals simultaneously, and a rather clever system for applying pesticides just where they're needed.

The Telltale Pill
Getting patients to comply with medication regimes is tough. We don't, as a rule, like to take medicines, even if we know that we should. Sometimes, however, after you've received an organ transplant, for instance, skipping your meds can be life-threatening. So how do you track whether patients are doing what they're supposed to? Medical device company Proteus has developed a neat way to monitor this by attaching tiny ingestible sensors (called Ingestible Event Monitors or IEMs) to pills; when the pills are swallowed, the stomach fluids activate the sensor, which then emits an ultra-low-power wireless signal to a microelectronic receiver stuck to the skin as an adhesive skin patch. The receiver portion of the Raisin system has achieved its FDA 501(k) clearance while the sensors are currently in clinical trials.

A Sleeker Electronic Nose
A key benefit of the various electronic noses that exist is their ability to identify complex odors by sensing a variety of chemical species simultaneously. Researchers from Imec and Holst Centre have developed a new gas sensor chip that could, they say, pave the way to an autonomous electronic nose. The chip incorporates microbridges in high-density arrays. These microbridges can be coated with a range of absorbents using inkjet printing, and each microbridge has an embedded piezoelectric shaker to allow it to vibrate independently. As target chemicals are absorbed onto the suitably coated microbridges, the microbridges' vibration modes change. The researchers are now working on integrating it with low-power analog read-out circuits. The chip itself is both very small and draws <1 µW/bridge, opening the path for smaller and lower power electronic noses for medical and food uses.

Smarter Weed Control
Sensors have been used to monitor water usage in agriculture as well as to ensure more efficient use of fertilizers. But until today, I hadn't heard of a project to figure out how to optimize the application of pesticides (or, as the researchers refer to them, 'phytosanitary products'). Led by Emilio Gil, the researchers at the Agricultural Machinery Unit, School of Agricultural Engineering of Barcelona, Universitat Politècnica de Catalunya (UPC), have outfitted a hydropneumatic sprayer with LIDAR, ultrasonic sensors, proportional solenoid valves, flowmeters, and pressure sensors. As described in the article, "UPC team designs electronic dosing system for vineyard pesticides" from AlphaGalileo, a portable computer in the tractor takes the data from the sensors and the tractor's GPS and uses it to make maps of the vegetation (coupling the LIDAR readings with the GPS locations). To determine how much to spray and where, the ultrasonic sensors measure the density of the vegetation. The computer's software then uses this data to calculate the flow rate of each spray nozzle and then adjusts the solenoid valves to control the rate at which the fluid flows from the sprayer. The system has been tested in several Spanish vineyards.