Researchers at RMIT University in Australia, in collaboration with a private biotechnology company in the United States, have successfully demonstrated the use of high-frequency radio waves to temporarily open bacterial cell walls and introduce new genetic material into them.
The newly introduced material allows bacteria to boost their energy to produce important drugs such as insulin.
Bacteria such as E. coli are the main force in genetic experiments around the world. The genetic material of this simple microbe can be easily modified by introducing smaller circular DN** segments, called plasmids, that carry information to perform specific tasks.
In research labs, this can help demonstrate the role of a particular gene or protein in cellular machinery. Plasmids can help bacteria produce chemicals that benefit human society in an industrial setting.
Introducing plasmids into E. coli is a challenging step, but the cell wall needs to be opened in a short period of time so that the plasmid can enter the cell. The opening must be reversible because the plasmid requires cellular machinery to function properly to do its job.
Traditionally, researchers have used a "heat shock" method in this step, in which bacteria are subjected to an electric shock when exposed to relatively high temperatures in the presence of plasmids. The electric shock opens the cell wall and allows the plasmid to enter the cell.
After that, the bacteria suddenly cool down and are expected to function normally. This has been the industry standard for the introduction of plasmids for many years. However, the effectiveness of this method is limited, as approximately 77% of cells have working plasmids.
Alternative methods use gentle laser pulses to make the cell wall conducive to plasmid uptake. However, only 30% of the cells were found to have taken up the plasmid in this method.
Plasmid DNA enters E. coli cells after being treated with high-frequency radio waves. **bio21institute
Previously, researchers at the Australian Centre for Electromagnetic Biological Effects Research have demonstrated the use of high-frequency electromagnetic energy to make cell walls more permeable.
The collaboration between RMIT's researchers and Minnesota-based W**Ecyte Biotechnologies now provides further evidence that the method can safely deliver DNA into cells.
The researchers used 18 GHz radio waves to turn the bacterial cells on for three minutes. After this, up to 91% of the cells received the plasmid, a figure significantly higher than traditional heat shock methods.
Our novel, cost-effective method proved to be highly efficient, but also gentler on the cells because no harsh chemicals or high temperatures were used in the process," said Elena Ivanova, professor at the Faculty of Science at RMIT. "As a result, cell viability is higher than other techniques.
Interestingly, this method can also be used on eukaryotic cells – cells seen in fungi, plants, other animals, and humans, paving the way for countless applications of this method.
We have only scratched the surface of the wide range of drug delivery applications that this approach could have in the microbiome** and synthetic biology," Ivanova added in the press release.
The findings were published in the journal Nano Letters.