Technology has Promise in Portable Virus Detectors

 


Opportunities for a rapid, sensitive, more convenient test for viral infections are intensifying in the light of viral outbreaks that have occurred over the past years, such as sudden acute respiratory syndrome (SARS) or bird flu (HN51). Moreover, a compact, portable device could be very useful in remote or developing geographical regions without easy access to sophisticated laboratory facilities.

Researchers at the University of Twente have developed an integrated optics interferometric sensor that has potential to provide highly sensitive, rapid screening for virus detection. The technology is amenable to miniaturization and mass production, and, therefore, has significant potential to be developed into a handheld, point-of-care device for use at, for example, emergency clinics or hospitals. Such a device would stand in contrast to current, more time-consuming virus detection methods that require fairly extensive sample preparation and may not yield results for several days.

The interferometric sensor works by having monochromatic light from a laser source coupled to a channel waveguide and guided into four parallel channels. The four channels include a reference channel and three measuring channels (used to monitor different viruses by coating the channels with appropriate antibodies). Upon exiting from the waveguide channels, the light generates an interference pattern (a pattern of bright and dark bands), which is recorded. Binding of a specific virus to the coated waveguide surface causes a corresponding phase change that is measured as a change in the interference pattern. Analysis of the interference pattern yields information about the amount of bound virus particles on different channels. The sensor system uses a 647 nm laser source and a 12-bit charge-coupled device (CCD) camera to record the interference pattern. The channels that guide laser light are contained on a silicon substrate.

Aurel Ymeti of the BioPhysical Engineering of Science and Technology, MESA+ Institute for Nanotechnology and BMTI Institute for BioMedical Technology, University of Twente, and the lead developer of the integrated optics sensor, told Sensor Technology that the technique is superior to traditional methods, such as polymerase chain reaction (PCR), due to its speed and ease of use without compromising sensitivity. He noted that, in principle, such a device has key potential for detection where minimal preprocessing of samples is required. Moreover, he noted that one could envision having several different, interchangeable detection modules for rapid viral detection. Moreover, there is the possibility of detecting multiple analytes. It can take on the order of five minutes for the sensor to determine the concentration of the virus being detected.

Ymeti noted that a rapid, sensitive, and convenient test for viral infections is essential for providing rapid testing and response to viral outbreaks (such as the SARS, HN51, and bird flu incidences over the past few years). Moreover, he added that a compact, portable device is potentially very useful in remote or developing regions that do not have ready access to sophisticated laboratory facilities.

Thus far, in a laboratory setting, the interferometric sensor has been tested to detect herpes simplex virus type 1 (HSV-1). The technologies that are, at present, generally used to detect such viruses as herpes simplex include PCR and branched DNA (bDNA). The researchers are able to detect the herpes simplex virus in both saline solution and in human serum (which can contain different proteins that can attach to the antibody, causing errors). At present, the sensor can detect HSV-1 when its concentration in serum is fairly high. To boost its application potential, it would be desirable for the sensor to be able to measure low concentrations in serum or various body fluids.

The sensor’s detection principle can be extended to any biological target for which there are specific antibodies available, such as viruses and proteins. In addition to HSV-1, other targeted types of viruses for the interferometric sensor include, for example, SARS, H5N1, bird flu virus, and so on.

Key issues that remain to be addressed (and that are required to achieve a commercially available sensor) are the design and development of a practical prototype and rigorous testing on clinical blood and serum samples. Paradocs Group BV, Netherlands, has been working on creating a commercial prototype of the sensor.

The goal is to eventually develop a sensor that simultaneously detects different viral diseases. Ymeti noted, "The multichannel character of the sensor allows sensing several (up to three in the current configuration) different viral diseases simultaneously. We have estimated that simultaneous detection of up to 20 different viral diseases is feasible for the same device configuration."

There are key opportunities for sensitive, more convenient and rapid systems and techniques for virus detection, since, currently, there do not appear to be any portable sensing devices that are readily commercially available and are used to detect viral diseases onsite in real-world applications.

Details:

Aurel Ymeti


PhD, BioPhysical Engineering (BPE)


Faculty of Science and Technology


MESA+ Institute for Nanotechnology and BMTI Institute for BioMedical Technology


University of Twente


Building Zuidhorst ZH165


PO Box 217


NL-7500 AE Enschede


Netherlands


Phone: +31-53-489-3870


E-mail: A.Ymeti@utwente.nl


URL: www.utwente.nl


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