Single bead parallel synthesis and screening.

Microstructured silicon wafers were employed as miniaturized solid-phase reaction vessels as well as miniaturized micro titer plates. Employing piezoelectric drop-on-demand liquid jets, a combinatorial library of 256 Peptides was synthesized on single beads. The synthesis protocol was associated to the location in the silicon nano-well arrangement. Products were photolytically cleaved in the same well that was used for synthesis and subsequently interrogated for thrombin inhibition in a homogeneous competition assay. The assay procedure was based on drop-on-demand liquid delivery and laser induced fluorescence imaging. The novel format proved useful for the integration of both synthesis and screening into one platform, a prerequisite for an iterative, evolutionary approach towards drug discovery.