UBC Reports | Vol. 50 | No. 3 | Mar. 4, 2004

Dr. Chu's Micro Gadgets

Mini sensors provide maximum data

By Celine Horner

Just as James Bond was always armed with amazing gadgets that Q secreted in his pens, watches, and Aston Martin cars, researchers at UBC's new Centre for Health and Environment Research (CHER) can now equip themselves with high-tech micro gadgets provided by the centre's micro sensor specialist, Winnie Chu.

CHER researchers rely on accurate measures of human exposure to air pollutants, noise, water pollutants, and workplace hazards among others to predict health outcomes and identify control strategies.

"One of the challenges in measuring personal exposure to environmental threats is taking measurements as unobtrusively as possible. Sensors must be discreet and lightweight so as to allow the wearer to continue their normal activity," according to Prof. Paul Demers, CHER's acting director.

In other words, there's no point in giving an ice hockey player a heavy briefcase-sized sensor to assess his exposure to gas from a Zamboni machine during a match.

Designing micro sensors to help researchers overcome these types of sampling obstacles is all in a day's work for Chu, who is CHER's fabrication specialist.

Top of her list at the moment is the development of a sensor that Prof. Kay Teschke can use to assess the impact of whole body vibration on truck drivers and other workers in heavy industry. Such a sensor would have to be worn comfortably by the driver and measure forces acting on the back muscles without changing the driver's posture or position. The sensor must also measure the vibration that the driver is exposed to from the jostling and jolting of the truck cab.

Chu explains that she will build two accelerometer sensors: one is worn on a belt that positions the sensor next to the muscle and measures its mechanomyographic frequency changes, and one that will be placed in the driver's seat to measure the forces due to vibration of the vehicle.

Mechanomyography measures the vibration frequency of individual muscle fibre contractions as the muscle moves. Each movement registers at a different frequency, but the higher the frequency the more likely that the muscle won't return to its original size or shape, much like a spring that has been pulled beyond its elastic limit.

"Accelerometers have been perfected and fine tuned in industry for use in crash impact air bags. They open at forces indicating a collision -- not if you slap the dash at the sight of yet another traffic jam. The back injury sensor, which will be smaller than the size of an aspirin, will yield data about muscle movement and the effects of external forces that will allow us to predict muscle strain and therefore avoid back injury," explains Chu.

Chu, who has a PhD in chemistry from Simon Fraser University, is likely to be in high demand by CHER's 31 researchers over this first year of the centre's operation. She is already working with Prof. Susan Kennedy on analytical lab methods to detect indications of inflammation in the exhaled breath of workers exposed to grain dust.

Asst. Prof. Karen Bartlett has enlisted Chu's help in building a sensor to monitor airborne fungal spores of the deadly Cryptococcus neoformans var. gattii, which has been the cause of a number of deaths on Vancouver Island. Another long-term plan is to build an indoor air quality sensor that will use artificial intelligence to eliminate background contamination and produce reliable readings for contaminants such as carbon monoxide.

The Michael Smith Foundation for Health Research has provided the funds for CHER which, in addition to micro sensors and state-of-the-art sampling techniques, provides researchers with assistance in grant facilitation, knowledge transfer and biostatistics.

The hope is that CHER research will involve few high speed car chases or gun battles and that, unlike Q's spy craft devices, Chu's micro sensors will not be destroyed in the line of duty.