Bacteria has Nowhere to Run, Nowhere to Hide

Bacteria has Nowhere to Run, Nowhere to Hide

Pathogenic bacteria continues to be a great threat to human health. According to US Centers for Disease Control and Prevention (CDC), more than two million Americans acquire bacterial infection annually, and 23,000 of cases are lethal (http://rt.com/usa/drug-resistant-bacteria-us-979/).

The proper diagnosis of bacteria is the first step toward successful control over infections. Unfortunately, current tests require significant time and specially equipped laboratories. The expedite diagnostics of bacterial infection in doctor’s office during the time of a regular visit would enable timely initiation of right treatment and minimize the number of medical visits.

Now researchers from the Department of Chemistry seem to approach to such a test using latest developments in DNA nanotechnology

DNA nanotechnology is a fast growing field that uses DNA molecules as building blocks to create arbitrary objects of nanometer scale (http://en.wikipedia.org/wiki/DNA_nanotechnology). Such shapes as smiling face, flask, map of Americas and others have been reported earlier. What if we fold a bacterial nucleic acid is something that is easy to detect?

Indeed, each bacterial cell contains large amounts of RNA molecules that are essential for protein synthesis. Bacterial RNA, which is structurally very close to DNA, can be folded in signal-producing particles, just like long DNA strands are folded in smiling faces and map of Americas in DNA nanotechnology.

The paper by Gerasimova and Kolpashchikov ‘Folding of 16S rRNA in a Signal-Producing Structure for the Detection of Bacteria’ describes an example of such approach (http://onlinelibrary.wiley.com/doi/10.1002/anie.201303919/abstract). In this study, dozens of DNA strands hybridize to a bacterial RNA to form 32 centers each of which produces a fluorescent signal. The approach enables detection of only 30,000 bacterial cells, which are present in a microscopic drop of a typical bacterial culture.

Next step in the technology would be to make signal readout of the sensor detectable by the naked eye and turning the technology into a strip format similar to that of the pregnancy test. So, for example, exposing the test strip to a sample will turn the color of the strip red if there is an infection, or to green if there is no infection.