Scientists Develop New Weapon in War Against ‘Superbugs’
Tiny DNA pyramids enter bacteria with deadly payloads
Bacterial infections usually announce themselves with pain and fever, and can often be defeated with antibiotics — but then there are “bugs” that are sneaky and hard to beat. Now, scientists in Singapore have built a new weapon against such pathogens in the form of tiny DNA pyramids.
In a study published in ACS Applied Materials & Interfaces, the investigators report that their nanopyramids can “flag” bacteria and kill more of them than can medicine alone.
The authors note that some infectious pathogens can lie in wait, undetectable in the human body or in places that antibiotics have a hard time accessing. Engineered nanomedicine offers a new way to deliver drugs directly into bacterial cells, but the carriers developed so far pose problems, such as toxicity.
Therefore, the researchers decided to use DNA to build a safer drug-delivery tool. They made little pyramids out of DNA that were so small that thousands could fit in the period at the end of this sentence. Then they attached gold nanomaterials as fluorescent tags and packaged actinomycin D (also known as dactinomycin) into the struts of the DNA pyramids.
In tests on Escherichia coli and Staphylococcus aureus, the scientists tracked the nanopyramids as they entered the bacterial cells and released their payloads. This killed 65% of the S. aureus and 48% of the E. coli, compared with 42% and 14% with actinomycin D alone.
Source: American Chemical Society; July 9, 2014.