by Fay Nolan-Neylan

Scientists in the US have developed a microdevice that investigates how bacteria communicate with each other to enhance their resistance to drugs. 

Bacteria communicate in a process called quorum sensing, in which they secrete small signalling molecules called autoinducers. When bacteria produce a quorum, their resistance to drugs is enhanced. William Bentley and co-workers from the University of Maryland have developed bio-inspired nanoscale factories that capture bacteria, deliver a drug right on the surface of the bacteria and test their responses.  'The overall goal is to understand how pathogens communicate with each other to make a more formidable team than each individual cell. We're trying to break down what exactly a quorum is and how it works', explains Bentley.

The nanofactories assemble themselves on a chitosan coated electrode within a microfluidic device. They contain multiple modules that each perform a different function, including targeting and capturing bacteria cells, sensing raw materials in the vicinity and converting the raw materials into autoinducer molecules and transporting these back to the bacteria cell surface. Bentley used bacteria cells that were specially constructed to express a fluorescent protein in response to autoinducer signalling, which could be easily seen. The autoinducer molecules made by the nanofactories triggered the quorum sensing response of the bacteria, causing them to express the fluorescent protein. 

'We're developing tools that enable rapid, cost-effective assembly of complex biological systems on devices so that the device can interrogate what the biology is doing', Bentley adds. 

Michael Shuler, an expert in bioengineering at Cornell University, Ithaca, US, called the concept of nanofactories 'highly intriguing and novel'. He said that while applying the technique to the capture of quorum sensing bacteria was important for controlling some types of bacteria without antibiotics, the most exciting thing for him was the potential of the nanofactories to be integrated with microfluidics or other nanotechnologies. 

In the future Bentley hopes that increasingly complex biological systems could be assembled to recreate the environment that bacteria see. He hopes to use the method to study other systems including epithelial and cancer cells.


Source: RSC