Immunoassays

 

The most simple and user-friendly form of immunoassays are the lateral flow immunoassays (LFIAs), occasionally also referred to as immunochromatographic tests. They are best represented by the pregnancy test strip, which has become a commercially highly successful diagnostic device suitable for direct end-user application.

 

Our research group is looking for approaches to overcome some of the inherent deficiencies of traditional LFIAs, which are the inability to provide quantitative assay results without the use of external readout equipment and the limited sensitivity. In this context, we for example aim at obtaining semi-quantitative information in the form of text or symbols directly readable from devices by the naked eye, in order to maintain the highest level of operational simplicity and user-friendliness commonly expected for LFIAs. To achieve this goal, we rely on the reproducible and flexible deposition of immunoreagents onto assay platforms by means of inkjet printing technology.

 

In other approaches, we apply luminescent antibody sensing proteins (developed by a co-researcher) that show a color change in their bioluminescence emission depending on the concentration of antibodies in a sample and that do not require a washing step. In contrast to conventional bioluminescence intensity-based signaling requiring timed signal readout under controlled conditions, the detection of color changes can be achieved by simplest means, such as a digital camera or a smartphone. These sensing proteins have been integrated into various porous assay substrate platforms. Besides the commonly applied nitrocellulose membranes, we are also working with materials such as cellulosic filter paper or cotton thread, allowing for on-device blood cell separation. The developed devices enable rapid assays (2-20 minutes) from minimal amounts of whole blood samples. Examples of target analytes include antibodies against HIV and Dengue fever, as well as therapeutic antibodies.

 

For specific information, please refer to our list of publications.