Technology has Promise in Portable Virus Detectors
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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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