A highly sensitive DNA nanosensor can detect lethal superbugs

Antibiotics have changed the field of treatment by making it possible to treat the most well-known microbial diseases today. However, the unregulated use has led to a major global antibiotic resistance problem.

As we continue to take antibiotics, sometimes at much higher doses than needed, disease-causing bacteria alter immune strategies to escape them. These drug-resistant bacteria, also known as “superbugs,” cause serious, difficult-to-treat and ultimately fatal diseases.

Methicillin-resistant Staphylococcus aureus (MRSA), a highly virulent group of superbugs affected by the antibiotic methicillin, is a leading cause of hospital-acquired infections. Proper and timely diagnosis is essential for effective treatment.

However, antibiotic sensitivity tests, the gold standard used to assess bacterial response to various drugs, are extremely lengthy processes and can take up to a few days to produce results. While other methods using enzymes and biosensors have shown some promise, they rely on external driving forces (such as electrical or magnetic energy) raising the element of uncertainty.

In their search for a simpler and more reliable search engine, researchers from Taiwan and Japan have now discovered a culture-sensitive DNA nanosensor without culture and self-driving that can detect superbugs deadly as MRSA.

The nanosensor is based primarily on Brownian motion, a term used to refer to the automated movement of random and erratic microparticles.

Excited about their results published in Biosensors and Bioelectronics.

We have designed a novel Brownian DNA nanosensor capable of specifically detecting MRSA DNA with high sensitivity, enabling rapid and accurate detection of microorganic DNA by diffusometry without DNA amplification or cell culture. “

Dr. Hiroaki Sakamoto, Research Co-author and Associate Professor, Fukui University, Japan

These sensors were prepared in three stages. First, the researchers prepared short strands of DNA, called oligonucleotide probes, that identified two different target sequences in MRSA DNA. To one of these probes, they attached fluorescent beads to be used for accurate visual measurement of particle movement.

To the other side, they bonded bulky gold nanoparticles, which reduce the diffusivity or mobility rate of the nanoparticles. When mixed with MRSA DNA, the researchers found that both the researchers were “sanding” the DNA, making the detection easy and quick. The researchers also confirmed the specificity of the sensor since it cannot bind other DNA from other bacteria such as Escherichia coli.

The team’s novel biosensor design not only eliminates the need for time-consuming and labor-intensive cell culture, but also simplifies sensory adjustment without the need for complex manufacturing, resources, and side-by-side energy sources. -outside. In addition, the nanosensor significantly reduces the detection time to just 10 seconds!

In addition, it has a low detection rate and can detect minute densities of up to 10 pM, thus enabling rapid and accurate diagnosis of infectious pathogens from very limited samples. It can also be customized for the detection of pathogens other than MRSA by altering the target DNA binding sequence.

Regarding the important long-term applications of their work, Drs. Sakamoto explains, “To match the threat from infectious pathogens, fast and simple diagnostic detection technology that may enable timely diagnosis and treatment is essential. Even if a new pathogen emerges , the social unrest that may result from the revolution can be reduced as much as possible in the future by the use of DNA detection sensors. “

In fact, their novel DNA nanosensor is a cost-effective and fast detection tool that can strengthen our fight in the fight against antibiotic resistance.


Magazine Reference:

Wang, JC, et al. (2020) Proof without methicillin-resistant culture Staphylococcus aureus using self-driving diffusometric DNA nanosensors. Biosensors and Bioelectronics. doi.org/10.1016/j.bios.2019.111817.