April 10, 2014
FRONTIERS IN MATERIALS SCIENCE
VINSE COLLOQUIUM SERIES
Dr. Paula T. Hammond
David H. Koch Professor in Engineering
Department of Chemical Engineering and Koch Institute of Integrative Cancer Research
Massachusetts Institute of Technology
"Electrostatic Nanolayer Delivery Platforms"
4:10 pm, 5326 Stevenson Center (Refreshments at 3:45)
Abstract: The alternating adsorption of oppositely charged molecular species, known as the electrostatic layer-by-layer (LBL) process, is a simple and elegant method of constructing highly tailored ultrathin polymer and organic-inorganic composite thin films. We have utilized this method to develop thin films that can deliver proteins and biologic drugs such as growth factors with highly preserved activity from surfaces with sustained release periods of several days; manipulation of the 2D composition of the thin films can lead to simultaneous or sequential release of different components, resulting in highly tunable multi-agent delivery (MAD) nanolayered release systems for tissue engineering, biomedical devices, and wound healing applications. Electrostatically assembled thin films provide a protective environment for these sensitive molecules, while enabling them to be released in a highly controlled fashion from complex substrates ranging from microtextured orthopedic implant surfaces to woven wound dressings. Depending on the nature of the LbL assembly, we can generate thin films that rapidly release proteins or peptides within minutes for rapid hemostasis, or release growth factors and small molecule therapeutics such as anti-inflammatory drugs from weeks to several months. Recent work has demonstrated that the controlled release of nano- to microgram quantities of growth factors such as BMP-2 can facilitate bone growth and osseointegration on surfaces to create high quality and high strength bone-biomaterial interfaces. We have introduced natural, biocompatible and safe nanomaterials that act as diffusion barriers or “gates” that can modulate the release further, or introduce staged delivery of different therapeutics using these types of materials systems or other simple chemistries to modify the nanolayer systems. On the other hand, siRNA and DNA can also be released from microscopic and millimeter scale structured surfaces for localized delivery directly through the skin or in the challenging environment of the wound. Multilayer “tattoos” derived from the transfer of LbL films with microneedles for transdermal delivery of DNA vaccines provides a promising route to address vaccination of difficult to target diseases. The generation of siRNA containing LbL systems for delivery to the woundbed can lead to accelerated wound healing and potential new treatments that would not be accessible using traditional polymer encapsulation methods.
Host: Dr. Craig Duvall
Dr. Paula T. Hammond