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Graphene-based biosensor enables ultra-sensitive detection of hepatitis C virus

An international team with CSIC participation has successfully developed and validated a biosensor for the ultra-sensitive detection of the hepatitis C virus (HCV). The device is based on graphene transistors that can detect key proteins of the virus. The results of this research appear in the journal Biosensors and Bioelectronics and the scientific team has already applied for the international patent of the invention.

As it is explained in the research, which is led by José Ángel Martín Gago, from the Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, biosensors based on graphene transistors “have become a promising tool for detecting a wide range of molecules (analytes)". Until now their performance was not as efficient as needed, but the joint work of these teams has come up with a novel solution: "we use a controlled physical method, based on vacuum technologies, to get the covalent functionalisation of graphene with a small molecule that binds to the probe molecule (in this case, an aptamer) therefore allowing the detection of the desired analyte. In this way we have managed to build ultra-sensitive aptasensors capable of detecting a key HCV protein," explains Irene Palacio, also from the ICMM and coordinator of the work.

The research shows that "the aptasensor has an extremely high sensitivity for the detection of this protein in human blood plasma, which belongs to genotypes 1 to 4 of the virus, genotypes that correspond to the 95% of infections," says the scientist. The biosensor developed is not only highly sensitive and stable, but also provides results in a few minutes, can be reused and is inexpensive.

Carlos Briones, from the Centro de Astrobiología (CAB), CSIC-INTA, explains that the detection of this virus is essential: "it is a pathogen of high clinical relevance, as it is the main cause of chronic hepatitis C and a trigger for liver cancer. In terms of prevalence, it is estimated that approximately 100 million people worldwide live with HCV virus and every year there are about four million new infections.

In this context, the aptasensor developed "specifically detects an HCV protein called ‘core’, which among other functions is responsible for forming the virus capsid," says Briones. Briones highlights that this newly developed technology "can be extended to different types of pathogens, such as other viruses with RNA or DNA genomes, bacteria, fungi or parasites.

To create this new biosensor, three complementary lines of research have been developed and combined: molecular biology, nanotechnology and microelectronics. On the one hand, at the Centre for Astrobiology (CSIC-INTA), scientists have obtained DNA aptamers with a high affinity and specificity against the core protein of the hepatitis C virus.

In parallel, the ICMM has developed a protocol for the covalent functionalisation of graphene, which is very stable and maintains the unique properties of this material. Finally, at the International Iberian Nanotechnology Laboratory (INL) in Braga (Portugal), biosensor platforms based on graphene GFET transistors have been built. In addition, the study has been complemented by the Institute of Physics (Czech Academy of Sciences) with a theoretical development explaining the sensing mechanism of the sensor.

"Our technology takes advantage of these lines of research in a synergistic way, allowing us to develop a graphene field-effect aptasensor (GFET) device," says Palacio. "Its main innovative feature is the high stability, reproducibility and sensitivity of the measurement, capable of detecting very low concentrations (in the attomolar range, 10-18 molar) of the HCV core protein".

The researcher highlights the applicability of the invention in the fields of biotechnology and biomedicine. For all these reasons, the authors are open to collaborations with other research groups, as well as with the private sector interested in licensing and exploiting the patent.

 

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