Label-free optical biosensor can detect rotavirus

Researchers at the Universidad Politécnica de Madrid (UPM) in Spain, using a label-free optical biosensor they developed, have found a way to enhance detection capacity of small concentrations of rotavirus, a contagious virus that can cause gastroenteritis (inflammation of the stomach and intestines) in infants and children.

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The biosensor can detect both the presence of the virus and its antibody, with the potential to also detect the pathogen in water and in blood plasma. The researchers say that this could allow developing countries to reduce high infant mortality caused by the virus.

Rotavirus diagnosis is usually made through an enzyme-linked immunosorbent assay (ELISA), a diagnosis method that must be performed by qualified staff in labs and require of supply of host enzymes. So Dr. Miguel Holgado Bolaños, who leads the Photonics and Biophotonics Optics lab at the Center for Biomedical Technology (CTB) at UPM, and his research team developed a label-free optical biosensor that does not require the presence of enzymes that fix either the substance to be detected or the marker responsible for any detectable physical phenomenon. These biosensors consist of smooth or micro-nano textured surfaces made with a polymer whose surface has been chemically treated to be similar to a bioreceptor.

Once the surface is coated by the bioreceptor, the biosensor is sensitive and selective to a determined type of biomolecule. So when the substance to detect is recognized by a bioreceptor, this substance produces a change on its optical response (transduction). This change is usually the movement of the maximum or minimum position of the interferometric pattern.

The biosensor features an interferometric system based on two Fabry-Perot interferometers. One interferometer is used as a reference and the other one captures the substance or virus. Different options of data are analyzed as an alternative to the traditional position shift of the endpoints. What's more, the biosensor can integrate with point-of-care devices and be used by non-expert users.

The researchers are working with a biotechnology company to develop a point-of-care device using the biosensor to detect pathogens and proteins in diverse application fields.

Full details of the research team's work appear in the journal Sensors; for more information, please visit http://dx.doi.org/10.3390/s140203675.

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