1. Switchable Polymer Interfaces for Bottom-up Stimulation of Mammalian Cells Igor Luzinov, Clemson University, DMR 1107786 The Materials Work Network project is within the framework of international cooperation between Clemson University, Clarkson University, UC Davis, Dresden Technical University, Leibniz-Institute for Polymer Research Dresden, University of Göttingen, and Institute for Analytical Sciences (in Berlin) laboratories. The ultimate goal of this project is to design and characterize a responsive polymer brush platform for the stimuli-triggered exposure of functional molecules to the bioengineered interfaces of mammalian cells. We expect to demonstrate stimulation of stem cells from the bottom-up using switchable mixed polymer brush. Up to date we developed synthesis of thermoresponsive Poly(N-isopropylacrylamide) [PNIPAM] – Poly(ethylene glycol) [PEG] mixed polymer brushes and studied their thermal response and interaction with proteins. The mixed brushes are significantly protein repelling independent of temperature, while demonstrating thickness change associated with temperature variation. We also synthesized mixed brush made of poly(ethylene glycol) methyl ether acrylate polymer (PEG-Acrylate) and PNIPAM-RGD that demonstrate thermoresponsive behavior. Temperature switching of specific cell adhesion to the mixed brushes functionalized with RGD-motive was found for a very narrow range of ratio between the polymers that requires further studies. Schematic of thermoresponsive polymer brush platform: (1) mixed brush, (2) substrate, (3) cell, (4) PS hydrophobic domain, (5) thermoresponsive chains: PNIPAM, (6) repelling chains: PEG, (7) interacting molecule; (8) interacting cell receptor. Optical microscopy images of fibroblast cells on (A and B) monobrush of PNIPAM-RGD and (C and D) binary brush of PEG-PNIPAM-RGD before (A and C) and after (B and D) cooling the samples to room temperature. A D C B

2. Top right: Igor Luzinov and Nadya Klep (Clemson University, MSE undergraduate student) supported by this project (including REU supplement). She conducted research during summer of 2012 and academic year of 2013. Matthew Booz, undergraduate Clarkson University student supported by this project (including REU supplement). He conducted summer research under the guidance of Sergiy Minko during summers of 2012 and 2013 The investigators involved undergraduate and graduate students and post-doctorate associate in the research and train them to gain (i) expertise in nanofabrication techniques, (ii) familiarity with modern concepts in biomaterials chemistry, (iii) the ability to synthesize and characterize nanostructured polymeric materials and biointerfaces, (iv) the ability to run experiments, gather data, and make discoveries. In Clemson University a PhD student worked on the project. The student prepared his PhD dissertation and defended his work on June 21, 2013. During summer of 2012 REU undergraduate female student was working on the project. The undergraduate student continued work during the academic year of 2012-2013. In summer of 2013 two SC HS students worked on the project under the guidance of a (freshly recruited for the project) PhD student. In Clarkson University, 1 MS student (who worked on the project) has graduated with a MS degree. Currently, the work on the project is conducted by a new PhD student. Two researchers have been involved on this project at UC Davis an undergraduate student and a postdoctoral fellow. Top left: Igor Luzinov and his 2013 summer students: Laura Smith (NSF REU student, San Jose SU), Charles Nikon (worked on this project, TL Hanna HS, Anderson, SC), and Daniel Freeman (worked on this project, Riverside HS, Greenville, SC). Switchable Polymer Interfaces for Bottom-up Stimulation of Mammalian Cells Igor Luzinov, Clemson University, DMR 1107786