doi:10.1038/nindia.2014.63 Published online 13 May 2014
produced a sensor that can detect traces of a protein found in a drug-resistant
bacterium1. They made the sensor using titanium dioxide nanotubes and carbon
electrodes. It could potentially be used to monitor the presence of the
bacterium in clinical samples.
The bacterium methicillin-resistant Staphylococcus aureus (MRSA), which causes skin infections in humans, is resistant to many antibiotics. In medical facilities, it can cause life-threatening bloodstream infections, pneumonia and surgical-site infections. However, existing techniques for detecting this bacterium are complex and expensive.
To devise a fast and simple technique for detecting S. aureus, the researchers fabricated the sensor by modifying screen-printed carbon electrodes using titanium dioxide nanotubes. They then carried out electrochemical studies to determine the efficacy of this sensor in detecting a penicillin-binding protein that acts as a marker for S. aureus.
The researchers found that the sensor detected the marker protein at very low concentrations down to 1 nanogram/microlitre. They discovered that the sensor could reproduce measurements on protein samples at this concentration for sample volumes as low as 30 microlitres.
The sensor also selectively detected the marker protein even in the presence of other diverse proteins such as the recombinant protein tyrosine phosphatase and bovine serum albumin. The sensor took a few minutes to detect the marker protein, which is faster than a conventional enzyme-linked immunosorbent assay.
The researchers anticipate that this sensor could be useful for rapid diagnosis of bacterial infections in resource-strapped developing countries.
1. Mandal, S. S. et al. Titania nanotube-modified screen printed carbon electrodes enhance the sensitivity in the electrochemical detection of proteins. Bioelectrochemistry 98, 46–52 (2014)