ANIM · Precisely Defined, Surface-Engineered Nanostructures via Crystallization-Driven Self-Assembly of Linear-Dendritic Block Copolymers

Precisely Defined, Surface-Engineered Nanostructures via Crystallization-Driven Self-Assembly of Linear-Dendritic Block Copolymers

Goals and key milestones: a) Synthesis of dendrons with alkyne focal points and crystalline homopolymers and block copolymers with azide terminal groups. b) Synthesis of linear-dendritic block copolymers with crystalline linear block. c) Self-assembly of architecturally different linear-dendritic block copolymers. d) Reporting of results in international scientific journals and at international conferences. e) Outreach As noted in the mid-term report, the above-mentioned milestones were encountered with some difficulties with respect to the self-assembly step (c). The issues were mainly due the sterics of the dendritic blocks. Consequently, these milestones needed to be modified to accommodate a less sterically-encumbered brush-type corona-forming block. As a result, the following new set of goals were set: a) Synthesis of an amphiphilic linear-brush block copolymer with a linear poly(ferrocenyldimethylsilane) crystalline block and a brush corona-forming block based on triethylene glycol-grafted poly(allyl glycidyl ether). b) Development of well-defined cylindrical micelles and block comicelles in aqueous media. c) Investigation of their potential applications in biomedical research. d) Reporting of results in international scientific journals and at international conferences. e) Outreach The research with new milestones has progressed very close to schedule (see below). a) The target amphiphilic linear-brush block copolymer was successfully synthesized in four steps in moderate yield. b) Self-assembly of the newly-synthesized polymer was investigated under various conditions. Cylindrical micelles and block comicelles of controlled dimensions were accessed in two steps via the living crystallization-driven self-assembly approach in dimethyl formamide followed by their dialysis against water. c) This goal was achieved by demonstrating the binding ability of the developed positively-charged triblock comicelles to DNA. This shows the potential application of these micelles as gene vectors. In addition, the cellular uptake of these well-defined block comicelles are currently underway. Our preliminary results show their efficient uptake by HeLa cancer cells. d) One manuscript has been published so far in the Manners group pertaining to the research proposal since the beginning of the fellowship (see below). In addition, new collaboration has been establish with Prof. George Banting group in the School of Biochemistry at the University of Bristol to evaluate the biomedical applications of these micelles. Moreover, this project has been extended to polylactide-based block copolymers as a more biologically-relevant drug delivery system. Results of the follow up studies will be published in high impact journals in near future. Furthermore, the fellow was involved in other research projects in the Manners group including the synthesis and self-assembly of Pt-pincer amphiphiles (see below) as well as functional two-dimensional platelets (manuscript in preparation) and block copolymer heteroepitaxial growth in two dimensions (manuscript in preparation). The fellow attended two international conferences in Canada (CSC, Ottawa 2015) and the United States of America (Inorganic Polymers, San Diego, 2016) and presented two talks. Nazemi, A.; Boott, C. E.; Lunn, D. J.; Gwyther, J.; Hayward, D. W.; Richardson, R. M.; Winnik, M. A.; Manners, I.* “Monodisperse Cylindrical Micelles and Block Comicelles of Controlled Length in Aqueous Media” J. Am. Chem. Soc. 2016, 138, 4484-4493. Boott, C. E.†; Nazemi, A.†; Manners, I.* “Synthetic Covalent and Non-Covalent 2D Materials” Angew. Chem. Int. Ed. 2015, 54, 13876-13894. †These authors contributed equally Robinson, M. E.; Lunn, D. J.; Nazemi, A.; Whittell, G. R.; De Cola, L.; Manners, I.* “Length Control of Supramolecular Polymeric Nanofibers based on Stacked Planar Platinum(II) Complexes by Seeded-Growth” Chem. Commun. 2015, 52, 15921-15924. e) Fellow was part of Bristol’s Bright Nights in 2014 and 2015 where the public was invited to learn about Science and Marie Curie projects. In addition, Dr. Nazemi presented 1 lecture in the graduate course “Recent Advances with Soft Nanomaterials” in the Department of Chemistry at the University of Bristol entitled “Directed Self-Assembly of Inorganic Nanoparticles”.

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