Lab-On-A-Chip Device To Follow Bio-Film Behaviour Lab-on-a-chip

Researchers have devised a micro-scale tool known as "lab-on-a-chip" to follow the behaviour of bio-films - slimy colonies of bacteria causing most infectious diseases.

Most bacteria exist as bio-films. Bacteria are single-celled organisms, but they rarely live alone, said John Younger, professor at the University of Michigan (U-M) Health System and study co-author. The device measures bio-films' resistance to pressure.

Bio-films experience various kinds of pressure in nature and in the body as they squeeze through capillaries and adhere to the surface of medical devices, for example.

Mechanical forces are at work when bodies defend against these bacterial colonies as well.

The micro-fluidic device provides the right scale. The channel-etched chip, made from a flexible polymer, allows researchers to study minute samples of between 50 and 500 bacterial cells that form bio-films of 10-50 microns in size. A micron is one-millionth of a metre. A human hair is about 100 microns wide.

The researchers found that the bio-films they studied had greater elasticity than previous methods had measured. They also discovered a "strain hardening response", which means that the more pressure they applied to the bio-films, the more resistance the materials put forth, said a U-M release.

The paper will be published in the July 7 edition of Langmuir.