Point-of-care Diagnostics One Biosensor for Multiple Diseases

The Fraunhofer IZM is coordinating the PoC-BoSens project, which comprises a transnational team from various specialist fields that developed a biosensor prototype that can reliably quantify the biomarkers for several infectious diseases in less than 15 minutes. This is made possible by a combination of photonic bottle microresonators based on optical fibers and a microfluidic system, facilitating point-of-care diagnostics for multiple diseases at the same time. In an interview, project coordinator Dr. Alethea Vanessa Zamora Gómez talks about the challenges the researchers had to overcome and explains how the PoC system works.

Dr. Alethea Vanessa Zamora Gómez, you and your team developed a rapid test that can test for multiple infectious diseases at the same time. How does it work?

Dr. Alethea Vanessa Zamora Gómez: The sensor is based on an optical principle. The sensor surface is coated with a bioreceptor layer, which – depending on the specific biomarker or target molecule in question — binds this biomarker. The bond prompts a change in the sensor’s optical properties.

Which diseases could be detected with this point-of-care diagnostic platform?

Dr. Zamora Gómez: We focused on the detection of cytokines as part of the research project. Those are small proteins associated with infections — including tuberculosis or Q fever — and autoimmune diseases. That said, the sensor can be adapted to detect any biomarker that binds to an antibody or an aptamer. Examples include biomarkers for cardiovascular diseases, biomarkers for various types of cancer, those related to COVID-19, etc.

Sensors with varying bioreceptor layers will be able to detect different biomarkers for different diseases. In this setting, the sensitivity pertains to the optical sensor, whereas the specificity applies to the bioreceptor layer.

The sensor involved a combination of photonic bottle microresonators with a microfluidic chip. What were the challenges and how did you manage to overcome them?

Dr. Zamora Gómez: It was difficult to integrate the small optical fibers (bottle microresonators) on a planar photonic chip as this required a special chip design and a high precision assembly procedure. At present, research laboratories with expensive and bulky equipment use these sensors. We found a solution to use them in a more practical fashion and make it possible to create a prototype of the product in the future. It takes a fully automated assembly procedure to achieve this goal. For now, the process is still semi-automatic.

How can photonic sensing platforms revolutionize point-of-care diagnostics?

Dr. Zamora Gómez: This is mostly owing to the optical sensors’ high sensitivity and the fact that they are micrometer sized, which makes it possible to house several sensors in a small cube. This can drastically reduce the chance of false positives and false negatives of existing rapid tests. High sensitivity sensors also help detect biomarkers in the early stage of the disease.

The project goal was achieved. What's next and when do you expect commercialization of the product?

Dr. Zamora Gómez: We are presently in an optimization and automation phase that could last between one to two years. Since we are a research organization, we would have to find a distribution partner to ensure successful commercialization, which means we don’t have a definite answer at this juncture.

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