DARPins have been developed in the Lab of Andreas Plückthun http://www.bioc.uzh.ch/plueckthun/index.php?pid=2-1-0. They are being commercialised by Molecular Partners http://www.bioc.uzh.ch/plueckthun/index.php?pid=2-1-0 . DARPins against a variety of interesting targets are being generated for the Affinomics Project http://www.proteinbinders.org/index.php. See this paper for a recent review: Plückthun, A. (2015). Designed Ankyrin Repeat Proteins (DARPins): Binding Proteins for Research, Diagnostics, and Therapy. Annu. Rev. Pharmacol. Toxicol. 55, 489-511. The original design of the DARPin library was published in this paper: Binz, H. K., Amstutz, P., Kohl, A., Stumpp, M. T., Briand, C., Forrer, P., Grütter, M. G., and Plückthun, A. (2004). High-affinity binders selected from designed ankyrin repeat protein libraries. Nat Biotechnol 22, 575-582. You find the full text of these (and many other) papers here: http://www.bioc.uzh.ch/plueckthun/index.php?pid=3-2-13