Detecting pathogens for less

An improved method for producing microarrays that can detect pathogens such as anthrax or small pox has been developed at the Pacific Northwest National Laboratory in the US.

An improved method for producing microarrays that detect pathogens such as anthrax or small pox has been developed at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) in conjunction with Washington State University (WSU).

Microarrays are tiny probes placed on a piece of glass or other material. Each probe is sensitive to a specific pathogen. The arrays are flooded with a complex mixture of DNA or RNA from environmental samples and individual probes react if particular pathogens are present.

The improvements developed by PNNL and WSU are in printing microarray sensors to speed the detection of pathogens such as anthrax and small pox. These improvements are expected to make the technology less expensive and more readily available for routine use by analytical laboratories.

‘Right now, DNA microarray sensors are found only in very large instruments in very few, high powered laboratories around the country. With this new approach we can fabricate these chips inexpensively, saving 80% of the cost of traditional methods and use the chips to look for multiple pathogens simultaneously, at rates much faster than conventional techniques,’ said Darrell Chandler, PNNL’s Principal Investigator on the project.

Traditional techniques print microarrays on glass slides through relatively expensive chemically modified probes. But Chandler and Douglas Call, from WSU, have developed an array printing system in which unmodified DNA probes are bound to glass surfaces. The modified printing method is stable at both high temperatures and low ionic strengths, making the fabrication method suitable for a wide range of conditions in common use.

‘The detectors allow for direct detection of RNA or DNA from multiple pathogens and offer potentially significant improvements in sensitivity compared with conventional techniques. And they can be applied to a broad range of fields from bioremediation to human and veterinary diagnostics,’ said Call.