The Smart Window is trying to balance several competing requirements for windows. Architects prefer transparency in the design of buildings for their aesthetic appeal. However, transparent windows may let in too much sunlight on a scorching summer day, causing interiors to become over-heated and then require artificial cooling. This is energy inefficient and leads to a bigger ecological footprint of a building. A team of architects, cell biologists, materials scientists, and electrical engineers initiated an eSkin project, aiming to apply our understanding of non-linear, dynamic human cell behaviors on geometrically-defined substrates to the design of energy efficient building skins. (Team: Jenny Sabin, Kaori Ihida-Stansbury, Nader Engheta, Jan Van der Spiegel, and Yang, supported by NSF/EFRI-SEED).