Single molecule detection

Modern medicine relies on specific and targeted medication. This is essential, for instance, in the context of antibiotic resistances. Selecting the most efficient medication often requires information on a bacteria’s genome. This information, however, is usually not readily available at the doctor’s office. Most of the molecular diagnostics is carried out in the clinical laboratory. 

Optical instead of chemical: antenna assays as an alternative to PCR

Typically, target molecules are detected in vitro with the help of specific fluorescence markers and using signal amplification mechanisms. For this process, PCR (polymerase chain reaction)-based methods are established in which the target sequence has to be copied several times. This requires comparatively complex equipment and qualified personnel.

In collaboration with LMU Munich, Fraunhofer IPM has developed a novel platform for pathogen detection on a single molecule level. The approach is based on optical signal amplification using so-called optical antennas. They eliminate the need for chemical amplification via polymerase chain reaction (PCR). Antenna-enhanced single molecules can be identified using comparatively simple, low-cost instrumentation.

Patient-oriented diagnostics: fast results for a wide range of applications

With its small footprint, high level of automation and potentially modest cost of production, the device demonstrates its suitability for single molecule sensing in POC applications.

The compact device carries out all reaction steps automatically without the user having to intervene. All reaction steps are conducted in a closed cartridge. The data is evaluated automatically. The result is available within an hour and is displayed on the monitor. This applies to multiresistant germs as well as to all types of DNA molecules.

In principle, the single molecule assay can be adopted to molecules beyond DNA, such as RNA and antibodies as well as antigens or enzymes. The method's functionality has been successfully verified by numerous tests.

© Fraunhofer IPM
The compact system carries out all reaction steps automatically, without the user having to intervene. The result is available after just one hour and is displayed on the monitor.