Electrical Sensors Diagnose Viruses

A technique has been developed that could form the basis of a noninvasive diagnostic method for Adenovirus.

The biosensor technology developed can detect the presence of the virus, and it can also identify the individual strain and the number of virus particles present.

Scientists at the University of Leeds (West Yorkshire, UK) fabricated novel immunosensors using polyclonal antibodies raised against a human Adenovirus (Ad5) capsid protein, which were selectively cleaved into antibody fragments by 2-mercaptoethylamine. The fragments were immobilized onto a functionalized conducting copolymer matrix comprising polyaniline and 2-aminobenzylamine.

The new technique therefore uses antibodies attached to an electrical sensor. By measuring the sensor's electrical changes, the investigators were able to identify how many virus particles were present, and determine the type of virus dependent on its response. They demonstrated that the immunosensor constructed shows high affinity to its Ad5 virus ligand, detectable by electrochemical impedance spectroscopy over a broad range of concentrations from 10 to 10¹² virus particles/mL, with a limit of detection (LOD) of 10³-virus particles/mL.

Currently, testing for viruses is complicated, time consuming and requires specialist preparation of samples to identify virus DNA. Testing for viruses could be much quicker, simpler, and ultimately less costly using this new technique. For patients, this sort of diagnostic would mean faster treatment. Adenovirus is a common virus found in vertebrates and causes many illnesses, from the common cold through to gastroenteritis. People with strong immune systems are not badly affected by the virus, but for those with a compromised or immature immune system, it can have fatal consequences.

Paul A. Milner, PhD, who supervised the study, said, "For the first time we've been able to test for the presence of a whole virus, rather than having to seek out its genetic material, and the first time the number of virus particles has been counted using a lab-on-a-chip device. These are both exciting developments.” ELISHA Systems Ltd. (Buxton, UK) will be the company commercializing this adenovirus biosensor and other biosensors for healthcare applications. The study was published on February 15, 2012, in the journal Biosensors and Bioelectronics.

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University of Leeds
ELISHA Systems Ltd.