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Specific detection of molecules for biosensors

10 May | By Christel Budzinski
Specific detection of molecules for biosensors
Image source: Fraunhofer Heinrich-Hertz-Institute
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The health system is facing the challenges of aging society and the rising costs of healthcare, especially in rural areas. Novel sensitive sensor systems in point-of-care test devices are one way to help reduce costs. The Fraunhofer Heinrich-Hertz-Institute (HHI) in Berlin has a mature technology for the production of low-cost sensors in large numbers. This technique offers itself to be transferred into the economy. For this reason, biosensorics has become interesting for the HHI as a market potential and as a contribution to the well-being of society. Miniaturized sensors have been developed, that can detect fast and highly sensitive molecules in liquids, gases and dusts. The chips of the silicon nitride sensors are available in large quantities. "Our goal is to provide physicians and patients with a novel measuring platform that enables fast, sensitive and easy-to-use tests. This allows patients to perform measurements directly, for which large laboratories are still needed today. This can significantly improve medical care, especially in rural areas" predicts project manager M. Sc. Moritz Kleinert. For this purpose, a particular waveguide-based ring resonator has been developed. Ring resonators are used in telecommunications as narrow-band filters. The existing know-how is to be marketed in collaboration with the medical application center of Charité and the companies First Sensor AG and SCIENION AG.

In principle, changes in concentration are measured via the refractive index change on the surface of the sensor. Photonic effects such as evanescent field coupling are exploited. First, however, the surface of the silicon nitride chips must be functionalized. This happens with so-called Aptamers (blue in graphic), which are single-stranded molecules whose structure is specifically adapted to the substance to be analyzed. The Aptamers bind the molecules sought (yellow in graphic) and shift the resonances in the waveguide by the resulting change in refractive index.

Various disciplines such as solid-state physics, photonics, communications technology, cell research and medicine bring their knowledge to bear here. All biological fluids such as blood serum, whole blood, urine, saliva, sweat and others can be used with this measuring principle for analysis. Also gases such as e.g. Explosive traces (TNT) or poison gas can be applied to the surface of the chips and analyzed there.

This method is predestined for use for point-of-care testing, both for use in clinics and medical practices, as well as mobile care and rescue services. Databases can be created and enable worldwide quick help. The molecular approach is very flexible over three orders of magnitude from nanometer to picometer. Label-free detection is possible with a measuring accuracy of approximately two orders of magnitude above the required detection limit. The sensor is a hand-held system, suitable for point-of-care testing, telemedicine and fast-priced blood analyzes. It has the advantage to manage with very small amounts of samples. This is particularly important when testing newborns for metabolic diseases. The device can also be used in rescue vehicles to clarify whether there is a stroke or a thrombosis. Patients in rural areas or disabled people can take the device with them. The measurement is often much faster - less than a minute - as measurements, which can only be carried out in the Central Laboratory. The measurement can be saved and stored on databases. The exchangeable sensor chips in the disposable handset are very cost-effective. Several ring resonators with different functionalization enable multi-parameter diagnostics. The HHI works closely with companies from the Berlin area to make this sensor solution market-ready.

Contact:
Moritz Kleinert, M. Sc.
Photonic Components Department
Hybrid PICs Group
moritz.kleinert@hhi.fraunhofer.de
Tel +49 30 31002-380
Fraunhofer Heinrich-Hertz-Institute
Einsteinufer 37
10587 Berlin, Germany
www.hhi.fraunhofer.de

I. A. Berlin Partner for Business and Technology GmbH

 

 

 

Category: Point-of-care
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