DESCRIPTION: We intend to refine the affinity-reagent discovery process so that it is not only cheaper and faster than currently possible, but also so that we produce reagents that are more versatile and useful than current monoclonal antibodies. We propose to use in vitro combinatorial recombination of pre-defined synthetic complementarity determining regions (CDRs) of single chain variable fragment (scFv) antibodies to synthesize a novel type of highly diverse synthetic display library. We have termed this new library-type as a 'pre-defined CDR' (PDC) library. This novel library system will have properties that will also enable it to greatly facilitate both the downstream affinity-reagent selection and the maturation processes. Methods for testing this library using microfluidics and emulsion screening are discussed.