Self-Assembly Approaches toward Directed Drug Delivery: from Patchy Micelles to MAD Nanolayers

Event Date: November 3, 2009
Speaker: Dr. Paula T. Hammond
Speaker Affiliation: Bayer Professor & Executive Officer
Department of Chemical Engineering
Massachusetts Institute of Technology
Time: 3:30 - 4:30 PM
Location: FRNY G140
Electrostatic and secondary interactions of polyelectrolytes and amphiphilic block copolymers can be used to generate new drug and gene delivery systems capable of controlled release triggered by pH or temperature. The 2D and 3D assembly of drug delivery systems will be addressed, including the generation of responsive, multi-agent thin films for localized targeting and controlled delivery from implant surfaces, and the generation of amphiphilic systems that enable highly controlled presentation of ligand for molecularly targeted chemotherapy agents. The manipulation of the solution assembly behavior of new amphiphilic and charged linear dendritic block copolymers, and their use as gene and drug carriers and in novel biomaterials systems will be described. We explore the role of cluster presentation of ligand on patchy micelles generated by the self-assembly of linear dendritic block copolymers. Key to this approach is the synthesis of new amphiphilic linear peptide-dendritic block copolymers that self-assemble in the solution state to generate stable micelles with highly branched, dense dendritic groups in the exterior shell. Due to the unique nature of the dendritic outer block, these micelles act as vessels with a highly tunable 3D presentation of ligand, enabling the creation of delivery nanoparticles with homo- or heterogeneous surfaces that enable cluster presentation of ligand. On the other hand, 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 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.

Professor Paula T. Hammond is the Bayer Chair Professor of Chemical Engineering at the Massachusetts Institute of Technology, and is currently serving as its Executive Officer. She is also a member of MIT’s Koch Institute for Integrative Cancer Research, and is a founding member of the MIT Institute for Soldier Nanotechnology. Paula Hammond earned her S.B. in Chemical Engineering from the Massachusetts Institute of Technology in 1984, her M.S. degree from Georgia Institute of Technology in 1988, and her Ph.D. in Chemical Engineering in 1993 from the Massachusetts Institute of Technology.     From 1993 to 1995, she held the NSF Postdoctoral Fellowship in Chemistry while working at Harvard University’s Chemistry Department.   


Her work encompasses two major areas: the development of new biomaterials via nano to microscale fabrication using directed and self-assembly of polymers, including drug delivery thin films with temporal control and novel polymer architectures for targeted nanoparticle drug and gene delivery; and self-assembled materials systems for electrochemical energy devices, including fuel cells, batteries and photovoltaics.  Her group has recently examined the linear-dendritic block copolymer construct as a means of presenting ligands on nanoparticles in highly controlled cluster size arrangements that impact intracellular uptake. Other areas of focus in biomaterials include the design of alternately assembled drug release systems that enable incorporation of a broad range of therapeutics, including biologic drugs such as growth factors, with temporal and sequential control. Professor Hammond was awarded the NSF Career Award, the EPA Early Career Award, the DuPont Young Faculty Award, and the Junior Bose Faculty Award at MIT. Recently her work in nanomaterials has been recognized and featured in several venues, including the journal Nature, the “Top 100 Science Stories of 2008” in Discover Magazine, the Popular Mechanics Breakthrough Award in 2006, The Economist, Forbes Magazine and Technology Review. Professor Hammond is an Associate Editor for the journal ACS Nano, and serves on the Advisory Board of several additional journals.   Other honors include Caltech Kavli Distinguished Lecturer, Radcliffe Fellow at Harvard University, Georgia Tech Outstanding Young Alumni Award, the Lloyd Ferguson Award for Outstanding Young Scientist, and Fellow of the American Physical Society.