Biological processes such as tissue generation take place in stages that involve the release or presentation of specific molecules and the chemical and physical signaling that ensues. Diseases such as cancer, as well as chronic disorders such as auto-immune conditions, often are a result of genetic dysregulation that leads to altered cell signaling and changes in tissue microenvironment. Ideally one would be able to achieve the release of small molecule drugs as well as biochemical signals such as growth factors, or siRNA and DNA to regulate genetic code, in a manner that can respond synergistically to the body’s natural processes. This process is difficult using more traditional polymer encapsulation. Using alternating electrostatic assembly as a tool, it is possible to build ultrathin film coatings nanolayers at a time with high amounts of drug loaded, through the use of complementary electrostatic or hydrogen bonding interactions. The nature of the layering process enables the incorporation of different drugs within different regions of the thin film architecture; the result is an ability to uniquely tailor both the independent release profiles of different therapeutics from the same film, and the order of release of molecules to targeted regions of the body. Multilayered release coatings as thin as a half micron to several microns can deliver growth factor proteins in a staged manner to achieve bone regeneration across large defects, or enable integration of bone into implants with high strength interfaces. siRNA can be released directly to wounds to correct the dysregulation of wound healing processes that have gone awry, from burn and scar tissue to the closure of chronic wounds such as diabetic ulcers. New microneedle vaccines can leave multilayer nanolayer systems within the skin for controlled vaccine delivery. These concepts of combination and staged release can be translated to nanoparticle systems that deliver drugs systemically. Decoration of chemotherapy drug loaded nano-carriers with electrostatic layers that encapsulate siRNA can silence the cancer genes that enable tumor cells to resist therapy. By enabling staged release of appropriate therapeutics, it is possible to greatly enhance synergistic efficacy in lung, breast and ovarian cancer. These nanolayered complex films on large or small surfaces can replicate or complement elements of the native healing environment, and orchestrate cellular processes for improved medicine.
Professor Paula T. Hammond is the David H. Koch Chair Professor of Engineering in the Chemical Engineering Department at the Massachusetts Institute of Technology and a member of MIT’s Koch Institute for Integrative Cancer Research. She serves as the Department Head of the Chemical Engineering Department at MIT. The core of her work is the use of electrostatics and other complementary interactions to generate functional polymer materials with highly controlled architecture. Her research in nanotechnology encompasses the development of new biomaterials to enable drug delivery from surfaces with spatio-temporal control. She also investigates novel responsive polymer architectures for targeted nanoparticle drug and gene delivery, and self-assembled materials systems for electrochemical energy devices. Professor Hammond was elected into the 2013 Class of the American Academy of Arts and Sciences. She is also the recipient of the 2013 AIChE Charles M. A. Stine Award, which is bestowed annually to a leading researcher in recognition of outstanding contributions to the field of materials science and engineering, and the AIChE Alpha Chi Sigma Award for Chemical Engineering Research. She was selected to receive the Department of Defense Ovarian Cancer Teal Innovator Award in 2013, which supports a single visionary individual from any field principally outside of ovarian cancer to focus his/her creativity, innovation, and leadership on ovarian cancer research. Prof. Hammond serves as an Associate Editor of the American Chemical Society journal, ACS Nano. As a part of the Year of Chemistry in 2011, she was one of the Top 100 materials scientists named by Thomson-Reuters, a recognition of the highest citation impact in the field over the past decade (2001-2011), and World’s Most Influential Scientific Minds in 2014. She is a Fellow of the American Physical Society, the American Institute of Medical and Biological Engineers, and the American Chemical Society Polymer Division. Professor Hammond’s work on multilayer tattoos for transdermal DNA vaccines was recently featured on the PBS Nova program, “Making Stuff” with David Pogue, and she was also featured in the Chemical Heritage Foundation’s Catalyst Series: Women in Chemistry.