Dr. Paul Van Tassel of Yale University will be speaking to the Department of Chemical Engineering and Materials Science on October 27 about "Layer-by-layer assembled polyelectrolyte films as porous biomolecular delivery systems."
Biomaterials capable of delivering controlled quantities of bioactive agents, while maintaining mechanical integrity, are needed for a variety of cell contacting applications. We describe here two strategies toward porous, polyelectrolyte-based thin films capable of controlled biomolecular loading and release. In one approach, termed "nanoparticle templating," films are formed via the layer-by-layer assembly of charged polymers and nanoparticles (NP), then chemically cross-linked to increase mechanical rigidity and stability, and finally exposed to tetrahydrofuran to dissolve the NP and create an intra-film porous network. In another approach, termed "solution shock," films are subjected briefly to an extreme acidic environment following LbL assembly, causing expansion and ultimately a spinodal-like breakup of the film into a porous structure. We report here on film structure and mechanics, on biomolecular agent loading and release, and on the behavior of cells cultured on these films. While both strategies yield mechanics and biomolecular agent loading that are suitable for applications such as tissue engineering, the solution shock method offers advantages in simplicity and controllability.
Paul Van Tassel is Professor of Chemical and Environmental Engineering at Yale University. His research interests include colloids/surfaces, polymers, biomaterials, and adsorption, and he has awarded grants from the National Science Foundation, the National Institutes of Health, the American Chemical Society, the Unilever Corporation, the Fulbright Foundation, and the Burroughs-Wellcome Fund. He has published over 80 peer-reviewed articles in the scientific/engineering literature. Paul holds a BA in Chemistry and Mathematics from Saint Olaf College (1987), and a PhD in Chemical Engineering from the University of Minnesota (1993).