Comprehensive coverage

Carbon nanotube sensors for protein detection

An aggregate of carbon nanotubes, coated with a thin layer of polymer, capable of detecting proteins, is used as a biosensor capable of receiving electrochemical signals to detect proteins in minute quantities. This biosensor could provide a new crucial diagnostic tool for the detection of a variety of diseases. The findings of the article were published by researchers from Boston College in the scientific journal Nature Nanotechnology.

Papilloma virus - HPV
Papilloma virus - HPV
The biosensor based on the nanotube was able to detect human ferritin, the main protein for carrying iron in cells, as well as the protein derived from the papilloma virus known as E7 oncoprotein. Additional experiments with the calmodulin protein showed that the sensor is able to differentiate even between the different configurations of the protein itself.

Molecular imprinting methods have shown that polymeric structures can be used to develop sensors capable of detecting individual organic compounds, however the detection of proteins faces complex challenges. The current research team used thread-like nanotubes coated with an insulating polymer capable of detecting proteins at a sensitivity level below picograms (10-12 of a gram) per liter.

The decisive part of the function of the sensor is the embedding of the protein particles within the insulating polymer coating. Since the rings reduce the thickness of the coating, those areas in the polymer contain a lower level of resistance than the rest of the polymer's insulation when it is connected to an electric circuit created from the charges present in the protein itself and the ionized salt solution. When a protein fragment enters its precise niche, it fills the space in the insulator and thereby causes the nanotube to experience a measurable change in resistance, a fact that indicates the presence of the protein in the sample.

The detection can be measured in real time, instead of the several days or weeks required for laboratory testing, that is - the molecular imprinting method of the nanotube could mark the way for the development of biosensors capable of detecting different viruses in a person weeks before available diagnostic methods that exist today.

Unlike the methods that exist today, in which the antibody level of the virus (for example the HPV virus) or the immune response of the cell is measured only after the initial infection, the nanotube sensor is able to detect the protein of the virus itself. In addition, with this method, there is no need to add a chemical marker for electrochemical detection.

"Regarding a number of diseases, it is impossible to know for sure why a certain person is infected with them," said the chief researcher. "All that can be known is that perhaps the cause of their outbreak is a virus. At this point in time, the patient may not have a measurable level of antibodies in their blood. Thus, precisely at the critical time for determining the correct diagnosis, it is possible that no traces of the virus will be found. Basically, you missed your chance. Now, we are able to detect the presence of the proteins found on the virus envelope through molecular imprinting and receive the correct diagnosis immediately."

The news about the study

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.