title: Nanoparticles assembled via pH-responsive reversible segregation of cyclodextrins in polyrotaxanes.
abstract: Supramolecular polymers with monomers bound together by secondary interactions, such as polyrotaxanes (PRXs), consisting of alpha cyclodextrin (αCD) threaded onto poly(ethylene glycol) (PEG), have attracted interest as a result of their ability to overcome physical limitations present in conventional, covalently structured polymers. Herein, we describe the formation of pH-responsive supramolecular assemblies from carboxyethylester bearing αCD and PEG PRXs. These PRXs were formed using PEG of Mw 20 kDa and a threading degree of 28%. Upon charge neutralisation the threaded αCDs co-localise, resulting in aggregation of the PRXs and the formation of a suspension by self-assembly. This process is shown to be reversible and possible via the mobility of CDs along the PEG guest chain. As a result of the inherent properties of PRXs, such as enhanced multivalent interactions and degradation, these responsive supramolecular polymers are expected to be of interest in fields where PRX-based materials have already found application, including paints, self-healing materials, surface coatings, and polymer therapeutics.
authors: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. fcaruso@unimelb.edu.au.
authors: Blaise L
authors: BL
authors: Tardy
authors: Polymer Science Group, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors: Shereen
authors: S
authors: Tan
authors: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. fcaruso@unimelb.edu.au.
authors: Henk H
authors: HH
authors: Dam
authors: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. fcaruso@unimelb.edu.au.
authors: Hirotaka
authors: H
authors: Ejima
authors: School of Pharmacy and Medical Sciences, Division of Health Sciences, The University of South Australia, Adelaide, SA 5001, Australia.
authors: Anton
authors: A
authors: Blencowe
authors: Polymer Science Group, Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
authors: Greg G
authors: GG
authors: Qiao
authors: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia. fcaruso@unimelb.edu.au.
authors: Frank
authors: F
authors: Caruso