A novel microsystem capable of detecting very low concentrations of pathogenic bacteria has been developed by scientists in California. This provides a potential tool for the discovery of early stages of bacterial infection.

The development of lab-on-a-chip systems for the differentiation and genetic detection of bacterial cells has been receiving continued attention within the area of biotechnology. 

The device developed by Hyongsok Tom Soh and colleagues at the University of California-Santa Barbara, USA, first concentrates E. coli, used as a model for many pathogenic bacteria, from a continuous flow of solution using a technique called dielectrophoresis. A set of microvalves further isolates and concentrates the bacteria by enclosing them in a chamber where the cells are lysed open, exposing the bacterial genome for detection by a specific optical sensor. This ability to integrate bacterial capture, concentration and genetic detection in one system has made it possible to detect as few as 25 bacterial cells in 30 minutes.

There is scope to combine other bioanalytical techniques into microsystems such as these, which would facilitate the isolation of specific cells based on multiple criteria simultaneously.

Katherine L Vickers