Could a pH meter help to deal with terror threat?

With the very real threat of biological terrorism hanging over our everyday lives, governments are having to consider how to deal practically with an attack. The first challenge will be to identify how a new weapon harms the body. To help deal with this challenge, a team of US researchers claims to have developed a device which measures how biological cells react to foreign substances.

Researchers from Vanderbilt University, Nashville, adapted a microphysiometer, which measures pH changes in biological cells, to monitor simultaneously variations in oxygen, glucose and lactic acid concentrations. The microphysiometer measures changes in acidity in a small chamber which holds up to one million individual cells. The Vanderbilt researchers added three additional sensors consisting of specially modified platinum electrodes.

In very basic terms, cells consume oxygen and glucose to produce lactic acid and carbon dioxide. Monitoring changes in the concentrations of these molecules should allow researchers to assess rapidly how chemicals affect them.

The Vanderbilt team tested their adapted device on Chinese hamster ovary cells using fluoride, which is known to prevent cells from converting glucose into ATP. The machine registered a drop in lactic acid concentration and an increase in glucose and oxygen levels, as the cells began to slow down. 'We could see the cells basically go into hibernation. Then, when we flushed out the fluoride, we could see them start up again,' notes David Cliffel, a Vanderbilt chemist who led the research team.

Cliffel is optimistic about the usefulness of the adapted device: 'I envision having a microphysiometer with an array of chambers. One of them contains kidney cells, another nerve cells and so on. Then, when an unknown agent is pumped into all these chambers, we quickly will be able to determine exactly which part of the body it attacks and the response of the affected cells will provide us with important clues about the manner of its attack.'

Emma Davies