title: Sterilizable gels from thermoresponsive block copolymer worms.
abstract: Biocompatible hydrogels have many applications, ranging from contact lenses to tissue engineering scaffolds. In most cases, rigorous sterilization is essential. Herein we show that a biocompatible diblock copolymer forms wormlike micelles via polymerization-induced self-assembly in aqueous solution. At a copolymer concentration of 10.0 w/w %, interworm entanglements lead to the formation of a free-standing physical hydrogel at 21 °C. Gel dissolution occurs on cooling to 4 °C due to an unusual worm-to-sphere order-order transition, as confirmed by rheology, electron microscopy, variable temperature (1)H NMR spectroscopy, and scattering studies. Moreover, this thermo-reversible behavior allows the facile preparation of sterile gels, since ultrafiltration of the diblock copolymer nanoparticles in their low-viscosity spherical form at 4 °C efficiently removes micrometer-sized bacteria; regelation occurs at 21 °C as the copolymer chains regain their wormlike morphology. Biocompatibility tests indicate good cell viabilities for these worm gels, which suggest potential biomedical applications.
authors.affiliation: Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, UK.
authors.forename: Adam
authors.initials: A
authors.lastname: Blanazs
authors.forename: Robert
authors.initials: R
authors.lastname: Verber
authors.forename: Oleksandr O
authors.initials: OO
authors.lastname: Mykhaylyk
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Ryan
authors.forename: Jason Z
authors.initials: JZ
authors.lastname: Heath
authors.forename: C W Ian
authors.initials: CW
authors.lastname: Douglas
authors.forename: Steven P
authors.initials: SP
authors.lastname: Armes
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002460:Cell Line; D002470:Cell Survival; D005782:Gels / Q000737:chemistry*; D006801:Humans; D008823:Micelles; D044367:Phase Transition; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013242:Sterilization; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D005782:Gels; D008823:Micelles; D011108:Polymers