ScreenFect transfection reagents are developed using patented combinatorial chemistry methods, which generates chemical libraries. Using these chemical libraries, candidate reagents are identified by high-throughput cell screening approaches. Finally, optimal reagents are further optimized for specific applications. ScreenFect transfection reagents can be used for transfection of nucleic acid molecules (pDNA, siRNA, mRNA, miRNA) as well as co-transfection of combinations of these.