DNA-protein binding force chip.

Force measurements provide new fundamental and complementary information on biomolecular interactions, particularly in the high and low affi nity regimes, which may hardly be obtained otherwise. [ 1 ] We introduce a label free parallel format assay to quantify the binding forces in protein–DNA complexes on a chip in crowded environments. It employs arrays of molecular force balances with fl uorescent read-out and fulfi lls all essential criteria for high throughput screening. The assay is fast, easy to operate and requires only a quantitative fl uorescence microscope as instrumentation. Despite years of intensive research, the need for a deeper understanding of protein–DNA interactions remains eminent. [ 2 ] A multitude of different techniques were introduced over the past years to characterize intrinsic affi nities and dissociation constants in low throughput formats. [ 3 ] However, the growing complexity of the systems e.g. in epigenetics or systems biology, spurs the urgent need for precise and reliable high-throughput methods, which can provide large data sets not only on the qualitative level but moreover give quantitative information on the underlying biophysics of protein– DNA interactions. [ 2 ]