Optical screening methods are of huge importance for a broad range of analytical issues. Fluorescence-based methods are highly significant for their high sensitivity, amongst other things. Important technological developments have focused, for example, on reducing sample volumes, increasing sample throughput (high-throughput screening, HTC) or on information content (high-content screening, HCS). With regard to screening methods, the ILM is currently focusing on the further development of (1) a particle-based method for bioanalytical applications and (2) a method (based on microtitre plates) for the selective investigation of cellular surfaces.
Established methods in molecular medical diagnostics are based on the spatial assignment of individual fluorescent samples in a microarray matrix structure (biochip). In order to reduce the technological workload, matrix-free methods are becoming increasingly important.
Researchers at the ILM have developed a new approach in which the individual analytes are assigned by way of microparticles of a defined size.
The evaluation of the coincidence of a certain scattering light signal with a certain fluorescence signal enables the identification of molecular interactions (e.g., hybridisation), which is important for molecular medical diagnostics.
Screening of cellular surfaces
In collaboration with the University of Aalen (Prof. Dr. Herbert Schneckenburger) ILM researchers have developed a screening method that focuses selectively on sample surfaces (e.g., cytoplasmic membrane of adherent cells).
The individual samples of a microtitre plate are simultaneously illuminated under total reflection conditions (multisplitting of a laser beam and multiple reflection of the partial rays in the glass bottom of a microtitre plate).
Since this method only captures fluorophores that are close to interfaces (in the case of cells, cytoplasmic membrane and adjacent cytoplasm), it is especially suited for screenings focusing on issues related to membrane-bound proteins (e.g., receptors) or membrane characteristics (e.g., fluidity).