1. Microfluidic Device Generating Stable Concentration Gradients for Long-Term Cell Culture: Application to Wnt3a Regulation of B-catenin signaling Vunjak-Novakovic, Gordana; Cimetta, Elisa; Cannizzaro, Christopher; James, Richard; Biechele, Travis; Moon, Randall T.; Elvassore, Nicola 2010 Articles Biomedical engineering