Engineering Block Copolymer and Hybrid Nanotechnologies of Well-Defined Architecture

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Amphiphilic diblock copolymers that are comprised of individual blocks of hydrophobic and hydrophilic repeat units (e.g. AAAAAABBBBBB) can be synthesized such that they self-assemble, under specific conditions, to form aggregates of well-defined shape and size at the nanoscale. At present, there is considerable interest in the production of stable nanotechnologies for use in a wide range of applications in the pharmaceutical and biomedical industries. To this point, it is largely only spherical shaped block copolymer aggregates that have moved forward to commercial development in these industries. For example, in the pharmaceutical industry, a number of anti-cancer drugs relying on formulation in spherical block copolymer micelles have moved into clinical development. However, beyond the spherical shape, amphiphilic copolymers can be engineered to form aggregates with simple, complex and/or hierarchical shapes. Importantly, the shape of copolymer aggregates has a profound impact on their performance such as loading capacity for hydrophobic and hydrophilic cargo, retention of cargo and transport properties in various media. To date, only a small number of established biocompatible copolymers (e.g. polyethylene glycol-block-polycaprolactone (PEG-b-PCL), PEG-b-poly(D,L-lactide) (PEG-b-PLA)) have been shown to reliably form non-spherical shapes, such as worm-like ‘filomicelles’ and vesicles, in aqueous solution. Thus, there is an interest in the design of new biocompatible copolymers that enable reproducible production of distinct morphologies in aqueous solution. Beyond encapsulation of hydrophobic and hydrophilic molecules, these amphiphilic block copolymers can be used to organize inorganic, metallic nanoparticles, such as gold nanoparticles (AuNPs) into well-defined 3D architectures. These polymer/metallic hybrid nanostructures possess unique properties and functionality, unattainable with the metallic nanoparticles alone, and have significant potential for use in biomedical applications such as imaging, photothermal therapy, radiation therapy and biosensors. Therefore, this NSERC proposal requests funding to support basic research into the design and development of new amphiphilic, biocompatible materials that enable production of stable supramolecular assemblies, of copolymer and drug or copolymer and AuNPs, of defined shape and dimension. The relationships between the composition of the copolymers, presence of model drug or AuNPs and shape and size of the copolymer aggregates formed in solution will be established. The fundamental knowledge gained through this research will enable on demand design of functional polymeric nanostructures of specific geometries and dimensions.