Fast diagnosis of exposure to nerve gas using biosensor

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TNO is developing a biosensor that makes it possible to determine with just a drop of blood whether someone in, say, Syria, has been exposed to nerve gas. The result is available within just a few minutes. You can then immediately administer an antidote and save a life. Biosensors are useful in other areas of medicine, too.

During the nerve gas attack involving sarin on the Tokyo metro on 20 March 1995, there were at least twelve fatalities, with thousands of people being injured. The hospitals were overwhelmed with people who thought they had been exposed to the gas. “As a result, some victims who had genuinely been in contact with sarin were unable to get help,” says Bart de Boer. He is a senior scientist and Biosensors project manager in TNO’s Optics expertise group. “At the time, there were no quick ways of determining who really needed help. With our optic biosensor system, this can now be achieved in just a few minutes.”

Exposure to nerve gas

“We can tell whether or not you have been exposed to nerve gas from the concentration of a specific type of protein in your blood,” continues De Boer. “You could call it the biochemical fingerprint of the nerve gas. We refer to a protein of this kind as a biomarker.” De Boer is working alongside principal scientist Daan Noort and his team from TNO’s CBRN Protection expertise group. For decades now, they have been working all over the world on the development of methods for diagnosing and verifying exposure to nerve gases and other weapons.

“We can tell whether or not you have been exposed to nerve gas from the concentration of a specific type of protein in your blood. We refer to a protein of this kind as a biomarker”

Quickly detecting biomarkers

The first optic biomarker detector experimental unit, FRESCO, is in the TNO laboratory in Delft. It is around 50 x 30 x 30 cm in size and not yet really very practical to use. “FRESCO stands for Free Space Coupling,” says De Boer. “You can create a wireless optic connection between the biosensor and the reading device. This means you can quickly change biosensors for a new reading. Our biosensor is a small optic chip with various sensors, each with a diameter of just 50 micrometres. These chips can be manufactured very inexpensively and will not cost more than a few pennies. They are disposable chips for using once. The sensors are so small that several can fit on a normal chip. You can then make each sensor sensitive to a different protein, which functions as a biomarker. It means that a number of biomarkers can be detected at the same time. Just one drop of blood is enough.”

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Point-of-care diagnosis

The reading device can be produced relatively cheaply, too. The portable version is perhaps slightly larger than a mobile phone. De Boer: “And that means this sensor technology really is suitable for point-of-care diagnosis. It allows diagnoses to be made quickly, at a patient’s home, at the doctor’s surgery, in the hospital, or in open areas in Syria. You can then deliver a rapid medical response.” With regard to diagnosing nerve gas, TNO and another company are currently investigating the possibilities for further developing the equipment for use in the field. Nonetheless, De Boer believes that a portable biosensor device of this kind will not be on the market for at least five years. “The device should also comply with European and American regulations on instruments for medical diagnoses. And that process takes a long time.”

“TNO and another company are currently investigating the possibilities for further developing the equipment for use in the field - in Syria, for example”

Diagnosing a heart attack in time

The optical biosensors can be used in many more areas of medicine, as well as for diagnosing nerve gas. “There are many more disorders for which biomarkers have been discovered,” explains De Boer. “However, its capacity for diagnosing illnesses and exposure to hazardous substances is still in its infancy. In that regard, there is still much work to do.” By way of example, TNO, Delft University of Technology, and Erasmus Medical Center in Rotterdam are carrying out experiments in the field of virus detection. De Boer goes on, “But so much more is possible, such as diagnosing a heart attack or a stroke at an early stage. It is vital to act quickly in such cases.”

Portable biosensor device on farms

“In the case of less acute medical diagnoses, examples include the early diagnosis of cancer by measuring different cancer biomarkers,” De Boer continues. “Vets could also use a battery-operated version of the device for making diagnoses on farms. And let’s not forget applications in resource-scarce environments in developing countries, such as in remote African villages without a medical centre or even a power socket.”

“So much more is possible, such as diagnosing a heart attack or a stroke at an early stage. It is vital to act quickly in such cases”

Diagnostic test as a consumer product

“In my view, diagnostic tests will increasingly become more of a consumer product in due course. You will be able to buy a biosensor at the pharmacy that you use to check certain aspects of your health. You then have a clearer picture of how you are. If necessary, you can make changes to your lifestyle or go to your doctor. But we at TNO cannot possibly develop all these opportunities ourselves. That is why we would like to team up with other parties with good ideas.”

Non-invasive blood sugar level sensor

TNO is working on several innovative measuring methods. A non-invasive sensor is being developed for diabetes patients, for example, that they can use to determine their blood sugar levels. It works by light shining on the skin, and then interacting with substances in the skin that are reflected and measured. This blood sugar level sensor is expected to be on the market by 2020.

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Bart de Boer MSc. Locatie Leiden - Sch + Page 1 Location: Location Delft - Stieltjesweg
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