synthesis-monodisperse-cylindrical-nanoparticles-via-crystallization

Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers

The production of monodisperse cylindrical micelles is a significant challenge in polymer chemistry. Most cylindrical constructs formed from diblock ...

University of Birmingham

The physical properties of cyclic and linear polymers are markedly different; however, there are few examples which exploit these differences in clinical applications. In this study, we demonstrate that self-assemblies comprised of cyclic-linear graft copolymers are significantly more stable than the equivalent linear-linear graft copolymer assemblies. This difference in stability can be exploited to allow for triggered disassembly by cleavage of just a single bond within the cyclic polymer backbone, via disulfide reduction, in the presence of intracellular levels of l-glutathione. This topological effect was exploited to demonstrate the first example of topology-controlled particle disassembly for the controlled release of an anti-cancer drug in vitro. This approach represents a markedly different strategy for controlled release from polymer nanoparticles and highlights for the first time that a change in polymer topology can be used as a trigger in the design of delivery vehicles. We propose such constructs, which demonstrate disassembly behavior upon a change in polymer topology, could find application in the targeted delivery of therapeutic agents.

Exploiting topology-directed nanoparticle disassembly for triggered drug delivery.

How to better control polymer chemistry.

The need for efficient, tailor-made catalysts has inspired chemists to design synthetic macromolecular architectures for selective catalysis. To this purpose, herein the synthesis and in-depth characterization of Ag(I)-crosslinked single-chain nanoparticles (SCNPs) is reported and their application as catalysts is demonstrated. Specifically, a copolymer of styrenic benzimidazolium chloride is synthesized as a linear precursor via reversible addition-fragmentation chain-transfer polymerization. Metalation of the benzimidazolium moieties by Ag(I) resulted in the intramolecular cross-linking of single chains via the formation of silver-N-heterocyclic carbene (Ag-NHC) linkages under dilute conditions. The successful formation of well-defined, robust SCNPs is evidenced by size-exclusion chromatography, dynamic light scattering, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. Finally, it is demonstrated that the Ag-SCNPs can be used as NHC pre-catalysts, by first indirectly evidencing the formation of the corresponding unfolded NHC-CS polybetaine and then organocatalysing a benzoin condensation reaction.

Article	Year
Exploiting topology-directed nanoparticle disassembly for triggered drug delivery. Biomaterials\| PubMed ID: 30048908	2018
How to better control polymer chemistry. Science (New York, N.Y.)\| PubMed ID: 30923210	2019
Catalytically Active N-Heterocyclic Carbene Release from Single-Chain Nanoparticles Following a Thermolysis-Driven Unfolding Strategy. Macromolecular rapid communications\| PubMed ID: 31162758	2019

Rachel K. O'Reilly

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