- by Caroline De Bie

New rapid dengue test could transform diagnostics


Dengue test delivers results

A team of scientists from the Universities of Denmark and Queensland published a paper in the Nature journal Scientific Reports describing the development of a new state-of-the-art dengue test. The diagnostic tool could help advance the fight against dengue fever.

This innovation is a quick dengue test that accurately detects one of the biomarkers of the virus, and is being further developed to detect additional biomarkers. The portable technology would bring laboratory-quality diagnostics to the field, making it possible to diagnose dengue fever with a procedure as simple as that of a glucose pinprick test.

 Blu-ray and a drop of blood

The team of researchers developed the biosensor based on existing Blu-ray consumer electronics combined with nanoparticle physics. They modified the Blu-ray unit to read a special cartridge containing a drop of blood mixed with magnetic nanoparticles to detect a key biomarker of dengue, known as NS1.

Thanks to this combination of technologies, clinicians can quickly and easily detect the presence of the NS1 molecule in the blood as well as immediately quantify the level of the biomarker. Dengue fever can be diagnosed by isolation of the virus, by blood serum tests, or by molecular methods.

Current dengue fever diagnostic tools consist either of traditional laboratory tests, which are time-consuming and require sophisticated equipment and trained experts, or else are very rudimentary, such as a paper strip test based on color-change, which is neither laboratory-grade nor quantitative.

Physical examination before vaccination, image courtesy of Prof Sri Rezeki Hadinegoro

According to Dr. Pratit Samdani, Associate Professor and Head of the Medicine Unit at G T Hospital and Sir J J Group of Hospitals in Mumbai, serum-based testing does not always yield conclusive results. “With the mutation of the virus, getting a serological diagnoses is not very easy in the first few days and sometimes it takes as much as a week to get a diagnosis,” he says. “If we had a sensitive and specific test available for dengue, using only a drop of blood, it would be a wonderful thing,” adds Dr. Samdani, who has already treated some 500 dengue patients in 2015 alone. “A quick diagnostic tool would be a big boon for the medical fraternity and patients.”

Dengue diagnostics expert, Professor Shamala Devi Sekaran of the Department of Medical Microbiology, Faculty of Medicine, University of Malaya, agrees: “General practitioners, in particular, want something quick, simple and definitive to use in diagnosing dengue fever.”

“Basically, it’s like a Nespresso coffee machine, where different cartridges can be introduced in the machine to perform different tests…”

According to Dr. Marco Donolato, formerly researcher at the Technical University of Denmark and now Chief Scientific Officer of the startup company BluSense Diagnostics, and one of the authors of the paper published in the Nature journal, their new technology is a “cheap and easy to use system, as simple to manipulate as a standard Blu-ray disc player.” Yet, he emphasizes, it can accurately detect the biomarker with the same sensitivity as specialized laboratory machinery.

Simple and quantitative

“We have demonstrated in the paper just published in Nature that we can detect the NS1 biomarker,” explains Dr. Donolato. “Since doctors would like to have three parameters tested, we are working on expanding the diagnostic capability to include other biomarkers in the same test.”

One of the key aspects of this technology is that the test uses just a single drop of blood from a pinprick to the finger with results in just seven minutes. “The fact that the test is easy enough to do and it can be done using whole blood rather than first separating the serum is significant,” emphasizes Prof. Sekaran, who has no affiliation with the paper’s authors or the company commercializing the product. This is in contrast to a hospital test in which significant amounts of blood are drawn and the laboratory results take several hours or days. Thus, treatment can be started immediately after the results are known.

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The device itself is compact, meaning it can be kept in a doctor’s office or brought along with a field technician to the most remote villages. And, because it has the ability to be cloud-connected, it could contribute to easily mapping outbreaks of the disease, suggests Dr. Donolato. In addition, the quantitative value of the diagnostic allows for a tailored treatment. “It is very important that it provides a quantitative level of NS1, which allows for more accurate diagnosis,” explains Prof. Sekaran.

Broader significance

According to Dr. Donolato, the nanotechnology crucial to this diagnostic tool, which consists of magnetic nanoparticles that mix with the blood droplet, means the system can be used to test for the existence of other parameters in addition to NS1. What is more, this nanotechnology is compatible with more than just the detection of dengue fever, but can also be used to detect biomarkers for a broader range of disorders, such as diabetes and other infectious diseases.

“Basically, it’s like a Nespresso coffee machine, where different cartridges can be introduced in the machine to perform different tests,” says Dr. Donolato. The spin-off company, BluSense Diagnostics, is working to bring this technology to market as quickly as possible. “A tool like BluSense sounds awesome, and I’m sure it would work very well in metropolitan areas, but there could be challenges in smaller towns, including cost, shelf-life, and availability of a technician or doctor,” says Dr. Samdani. “More important is the specificity and the sensitivity. It needs to be scalable, comparable and better than the antigen and antibody test, which of course the paper does mention.”

“It still needs to be tested out in the field,” adds Prof. Sekaran. The BluSense team is now developing the final system, which will be field-tested in 2016, according to Dr. Donolato. If the tests are conclusive, and the device receives regulatory approval, hospitals may soon equip themselves with a tool that could significantly increase effectiveness in dengue diagnosis.

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