I. Functional Biodegradable Polymers
Biodegradable polymers are of increasing interest for a wide range of applications including tissue engineering, drug delivery, and medical devices. We have been developing biodegradable polymers that degrade by novel mechanisms, potentially allowing for unprecedented control over the degradation rate and for the triggering of polymer degradation under specified conditions. For example, we are developing new "self-immolative" polymer backbones, which depolymerize by an end-to-end mechanism upon the cleavage of a stimuli-responsive end-cap from the polymer terminus. We are studying their depolymerization and exploring their potential for various applications. In collaboration with Dr. KIbret Mequanint's group in the Department of Chemical and Biochemical Engineering at the University of Western Ontario we have also been developing poly(ester amide)s with pendant functional groups that can be used for the conjugation of drugs or cell signaling molecules such as growth factors. These materials are currently being explored for tissue engineering and drug delivery applications.
II. Macromolecular Assemblies as Biomaterials
Recent developments in controlled polymer synthesis, and the imaging of polymeric assemblies provide access
to a wide variety of systems ranging from hydrogels to micelles, worms, vesicles, and nanoparticles. The properties of these systems can be controlled by the structures of the constituting polymers, and the conditions under which they are assembled. The potential applications of polymeric assemblies in biology and medicine are very diverse ranging from the delivery of small molecules, proteins, and DNA in vivo, to their use as scaffolds for tissue engineering.
To realize the potential for polymeric assemblies in medical applications, significant progress is still
required to control their behaviour, particularly in vivo under biological conditions. Here we are focusing on
preparing new functional and biodegradable polymers, and using these to make polymer assemblies with controlled biological behaviour. In addition, we are working on functionalizing polymer assemblies with specific chemical units, either to control their localization in the body or to impart specific biological properties. Assemblies of self-immolative and other stimuli-responsive assemblies allow us to trigger the assembly and disassembly of these materials in a controlled manner.