(5ag) Polymer-Directed Self-Assembly as a Highly Flexible Route to Multifunctional Nanomaterials

With recent advances in nanotechnology, a large variety of single-component nanomaterials (i.e. polymer nanoparticles, carbon nanotubes, gold nanoshells, and quantum dots) have been developed for therapeutic and diagnostic applications. The next phase of development aims to construct multicomponent nanoscale entities which combine several functional properties into an integrated system. Nonetheless, the efficient and reproducible preparation of strategically engineered multifunctional nanomaterials is a significant challenge. Conventional approaches typically rely on unique synthetic routes tailored for the chemical linkage of individual components, making the development process lengthy and prohibiting independent optimization of individual components. Chemical strategies may additionally complicate facile incorporation of newly discovered materials into already existing constructs.

To overcome these limitations, a modular technology for the preparation of multifunctional nanoparticles using directed self-assembly of components is developed. The technology allows for the integration of materials of various properties based solely on thermodynamic driving forces, negating the need for explicit chemical modification of components. The key to the process is the control of times scales for micromixing, self-assembly, flocculation, and nucleation and growth, enabling particles of complex composition to be formed. Using this technology, stable and uniform composite nanoparticles simultaneously encapsulating nanocrystalline imaging contrast agents and organic drug molecules could be prepared with tunable sizes between 50-500 nm, high concentrations of encapsulated components, and precise control of component compositions, enabling multifunctional applications in drug delivery, medical imaging, and diagnostics. Based on this technology, novel particulate systems for MRI contrast enhancement and photodynamic therapy were developed. Finally, controlled functionalization of particle surfaces with disease-targeting ligands was demonstrated, allowing for directed delivery via a synergistic combination of passive and active targeting strategies. The technology provides a comprehensive and highly flexible platform for the tailored design and preparation of multifunctional nanomaterials in an economical and scaleable manner.