Department Seminars: Polymers at Synthetic and Biological Surfaces

Speaker Prof. Dr. Harm-Anton Klok Ecole Polytechnique Fédérale de Lausanne (EPFL) Institut des Matériaux, Laboratoire des Polymères

Host Department of Chemical and Biomolecular Engineering

Date/Time 04 Apr - 04 Apr, 11.00AM

Venue E5-03-19 , Faculty of Engineering, National University of Singapore

Synopsis

Polymer science provides a diverse toolbox to modify and control the properties and function of both synthetic and biological surfaces. The first part of this lecture will focus on synthetic surfaces and discuss the use of surface-initiated, controlled radical polymerization (SI-CRP) techniques for the preparation of thin, surface tethered polymer films. Surface grafted polymer films produced via SI-CRP are often colloquially referred to as polymer brushes. SI-CRP reactions are characterized by a number of unique features, which include the ability to (i) prepare polymer brushes with precise control over chemical composition and film thickness; (ii) generate polymer films that present very high surface concentrations of functional groups; (iii) conformally coat both simple, planar substrates as well as complex, 3D structured or porous substrates and (iv) tune the conformation of the surface grafted polymer chains by engineering the average distance between neighboring anchoring points. This presentation will highlight recent work from our laboratory that illustrates the use of SI-CRP to generate thin polymer films with sensory or responsive properties as well as results from recent work, which shows that the stretched conformation of these surface grafted polymer chains also has an impact on their chemical reactivity, potentially opening avenues towards novel mechanically responsive surfaces.

The second part of this talk will concentrate on biological surfaces and more specifically the membrane of living cells. Living cells, and in particular those from the adaptive immune system, are attractive as carriers to mediate transport of drug-loaded micro- or nanoparticles as they potentially provide possibilities to home in to the disease site in a highly selective manner. The successful use of cells as carriers for polymers and polymer particles requires chemical approaches that allow to immobilize (and release) the polymer or particle payload from the cell surface, without compromising cell viability and function. This presentation will discuss various polymer cell surface modification strategies and compare these different approaches in terms of the possibilities they offer to modify cell surfaces as well as their impact on cell viability and function. It will be shown that under appropriate conditions live cells can be surface modified with synthetic polymers while retaining their viability and functional properties.

Biography

Harm-Anton Klok is Full Professor at the Institutes of Materials and Chemical Sciences and Engineering at the Ecole Polytechnique Fédérale de Lausanne (EPFL) (Lausanne, Switzerland). He studied chemical technology at the University of Twente (Enschede, The Netherlands) from 1989 to 1993 and received his Ph.D. in 1997 from the University of Ulm (Germany) after working with Martin Möller. After postdoctoral research with David N. Reinhoudt (University of Twente) and Samuel I. Stupp (University of Illinois at Urbana–Champaign, USA), he joined the Max Planck Institute for Polymer Research (Mainz, Germany) in early 1999 as a project leader in the group of Klaus Müllen. In November 2002, he was appointed to the faculty of EPFL. Since 2012 he is Director of the Institute of Materials (~ Department Head) and also directs the Molecular and Hybrid Materials Characterization Center at EPFL. His research interests include polymer surface and interface science, polymer nanomedicine and polymer synthesis and functionalization. Harm-Anton Klok is recipient of the Arthur K. Doolittle Award of the American Chemical Society (2007) and is Associate Editor of the American Chemical Society journal Biomacromolecules and serves or has served on the editorial advisory board of Eur. Polym. J., J. Polym. Sci. A: Polym. Chem., Macromolecules, ACS Macro Letters as well as Macromol. Rapid Commun. and Macromol. Bioscience. He has been a Visiting Professor at the University of Bordeaux (France) and the University of Massachusetts/Amherst (USA), is a Chair Professor at the College of Chemistry, Chemical Engineering and Materials Science, Soochow University (Suzhou, China), guest professor at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun (China), Shanghai University (Shanghai, China) and Nanyang Technological University (Singapore) and was awarded a Chinese Academy of Sciences visiting professorship for senior international scientists (Institute of Chemistry, Chinese Academy of Sciences, Beijing).