Cornelia Reuter and Walter Hauswald Have Developed an Optical Biosensor That Detects DNA and Proteins Without Labeling

Using light, the sensor makes biomolecules visible – completely without dyes or chemical markers. Developed with the micro- and nanotechnology team in the cleanroom at Leibniz IPHT, the technology could make diagnostic procedures faster and easier.

In Dr. Cornelia Reuter’s hands, the sensor shimmers like a rainbow. When she slightly tilts the chip in the light, the colors shift – from green to blue to warm yellow tones. This play of colors is no coincidence, but rather part of the technology: The sensor uses light diffraction to identify biomolecules such as DNA or proteins. The goal is to precisely detect a specific DNA sequence or a particular epitope. Epitopes are tiny structures on the surface of a protein to which antibodies can bind specifically – a principle widely used in diagnostic tests to reliably detect diseases.

Colors That Reveal More Than the Eye Can See

“The color pattern indicates that the surface of the sensor is covered with microscopic structures,” explains Cornelia Reuter from the Applied Biospectroscopy and Bioassays group. These fine grid structures diffract light to varying degrees – depending on whether and which molecules, such as antigens or DNA strands, are bound to the surface. This makes biomolecular interactions directly visible, without dyes or labels.

Technology From the Cleanroom

The sensor can detect multiple different biomolecules simultaneously, which makes it particularly interesting for medical diagnostics. “We can, for example, detect nucleic acids and antibodies against SARS-CoV-2 in a single measurement,” says Reuter. This not only saves time, but also simplifies sample preparation.

The sensitive micro- and nanostructures of the sensor were manufactured by the team at the Center for Micro- and Nanotechnologies, led by Dr. Uwe Hübner – in close collaboration with Dr. Walter Hauswald.

With his technology group Sensor Systems and System Integration, he developed the optical readout unit that enables fast and precise detection. “Our task was to exploit the physical principles in such a way that the sensor is reliable and easy to use,” explains Hauswald. The readout unit selectively suppresses interfering light components and captures only the diffraction patterns that result from the binding of biomolecules.

Teamwork for More ­Accurate Diagnoses

To enable targeted use of the sensor in diagnostics, Cornelia Reuter and Walter Hauswald closely collaborated with Prof. Dr. Ralf Ehricht and Dr. Sindy Burgold-Voigt. Their team from the research department “Optical Molecular Diagnostics and System Technology” combines molecular detection methods with optical techniques – a synergy that enables faster and more accurate identification of infectious diseases.

Within the MultiHoloDiag research group at the InfectoGnostics Research Campus Jena, a flexible system was developed that can be adapted depending on the medical question.

“We see potential for diagnosing infectious diseases, but also for monitoring chronic conditions,” says Cornelia Reuter. The system can be flexibly adapted and is suitable for both clinical laboratories and research. There is significant potential for this sensor technology to be adjusted to suit various medical applications – from infection diagnostics to personalized medicine.

Original publication: https://doi.org/10.3390/bios14080398