Crystallisation-Driven Self Assembly (CDSA)
Crystallisation-Driven Self Assembly (CDSA) has emerged as a powerful technique for accessing 1D and 2D anisotropic nanostructures with a high degree of dimensional control. Contrary to traditional self-assembly techniques, CDSA is performed using block copolymers comprised of a solvophilic block and a semi-crystalline block. This technique exploits the ability of semi-crystalline polymers to form self-assemblies with low interfacial curvature, a favoured process induced by the crystallisation of the core-forming block after heating above the glass transition temperature and cooling down in a poor solvent. As a result, nanostructures with anisotropic morphologies and high solution stability can be produced, using polymers easily accessible through combined ring-opening and RAFT polymerisations. Within the group, we have extensively studied how changing the block copolymer chemistry and composition can be used to modulate the dimensions of the resultant assemblies, such as selectively targeting rod- or plate-shaped morphologies, or producing cylindrical micelles with tunable lengths and diameters.
The research in our group therefore focuses on two main areas: fundamental investigations into the CDSA of biodegradable semi-crystalline polymers, and subsequently studying their application potential in fields such as drug delivery and tissue engineering.
Understanding CDSA of Degradable Polymers
Our group has pioneered research in the CDSA of biodegradable and biocompatible polyesters such as poly(lactide) and poly(caprolactone). Particularly, we have focused research attention on exploring how polymer length, composition and chemistry can be altered to rationally tune nanoparticle shape, and the further development of new polymeric systems that are amenable to CDSA. We aim to elucidate fundamental insights into the CDSA process, such as pathways of assembly (external nucleation vs self-nucleation) and how these are influenced by the solubility of the constituent blocks in the assembly solvent. Recently, the group has been investigating how CDSA particle dimensions can be precisely controlled with precision, through a ‘living’ CDSA mechanism, as well as the possibility of building complex ‘multiblock’ structures with chemically distinct units, controlled degradation and responsive behaviour.
Getting into Shape: Reflections on a New Generation of Cylindrical Nanostructures Self-Assembly using Polymer Building Blocks, J.C. Foster, S. Varlas, Benoit C. Couturaud, Z. Coe, R.K. O’Reilly, J. Am. Chem. Soc, 2019, 141, 7, 2742–2753, DOI: 10.1021/jacs.8b08648
Length Control of Biodegradable Fiber-Like Micelles via Tuning Solubility: A Self-Seeding Crystallization-Driven Self-Assembly of Poly(ε-caprolactone)-Containing Triblock Copolymers, W. Yu, J. C. Foster, A. P. Dove, R. K. O’Reilly, Macromolecules, 2020, 53, 4, 1514–1521, DOI: 10.1021/acs.macromol.9b02613
1D vs. 2D shape selectivity in the crystallization-driven self-assembly of polylactide block copolymers, M. Inam, G.Cambridge, A.Pitto-Barry, Z.P. L. Laker, N.R. Wilson, R.T. Mathers, A.P. Dove and R.K. O’Reilly, Chem Sci, 2017, 8, 4223–4230, DOI: 10.1039/C7SC00641A
Novel Applications of CDSA Nanostructures
The multidisciplinary nature of our group and collaborators has allowed us to leverage our fundamental CDSA research into a wide array of exciting applications. Particularly, we are interested in how control over nanoparticle shape and size can influence the resultant properties, and subsequently use these insights to guide the design of particles towards bespoke applications. These projects have ranged from using platelet particles as emulsion stabilisers, where large platelets were more effective than small ones regardless of surface chemistry, through to investigating the antimicrobial properties of charged particles, with small diamonds outperforming larger ones. More recently, research has focused on exploring the role of nanoparticle shape in directing biological interactions, such as cellular uptake and immune response, as well as the ability to modulate hydrogel mechanical and adhesion properties when used as fillers for antimicrobial and tissue engineering applications.
Shape effect of glyco-nanoparticles on macrophage cellular uptake and immune response, Z. Li, L. Sun, Y. Zhang, A. P. Dove, R. K. O’Reilly, G. Chen, ACS Macro Lett., 2016, 5, 1059-1064, DOI: 10.1021/acsmacrolett.6b00419
Controlling the Size of Two-Dimensional Polymer Platelets for Water-in-Water Emulsifiers, M. Inam, J. R. Jones, M. M. Pérez-Madrigal, M. C. Arno, A. P. Dove, R. K. O’Reilly, ACS Central Science, 2018, 4 , 63–70, DOI: 10.1021/acscentsci.7b00436
Exploiting the role of nanoparticle shape in enhancing hydrogel adhesive and mechanical properties, M. C. Arno, M. Inam, A. C. Weems, Z. Li, A. L. A. Binch, C. I. Platt, S. M. Richardson, J. A. Hoyland, A. P. Dove, R. K. O’Reilly , Nat. Commun., 2020, 11, 1420-1428, DOI: 10.1038/s41467-020-15206-y