ω-Pentadecalactone (PDL) was copolymerized with lactones of varying sizes (6-, 7-, 9-, and 13-membered rings) in order to characterize the properties of PDL copolymers throughout the lactone range for copolymerizations catalyzed by magnesium 2,6-di-tertbutyl-4-methylphenoxide (Mg(BHT) 2 (THF) 2 ). Kinetics of the copolymerization reactions were studied using quantitative 13 C NMR spectroscopy, which revealed that the polymerization of the smaller, strained lactone monomer occurred rapidly before the incorporation of PDL into the polymer. Furthermore, all polymers were randomly sequenced as a consequence of transesterification side reactions that occurred throughout polymerization. The copolymers were all shown to cocrystallize to produce polymers with melting and crystallization temperatures that displayed a linear relationship with respect to monomer ratio. Differences in degradation behavior of the smaller lactones enabled the synthesis of PDL copolymer materials that displayed independently controllable thermal and degradation properties.

The ‘immortal’ ring-opening polymerization (iROP) of pentadecalactone (PDL), catalysed by magnesium 2,6-di-tert-butyl-4-methylphenoxide (Mg(BHT)2(THF)2) under non-inert conditions is reported for the first time.

We report the one-pot copolymerization of ω-pentadecalactone (PDL) to produce tri- and diblock-like copolymers with the ability to undergo postpolymerization modification. The ε-substituted ε-lactone (εSL), menthide (MI), was copolymerized with PDL to introduce side chain functionality into poly(ω-pentadecalactone) (PPDL) copolymers. The copolymerization was followed by quantitative 13C NMR spectroscopy, which revealed that the polymerization of MI occurred before the incorporation of PDL into the polymer chain to form a block-like copolymer. Transesterification side reactions were not found to occur interblock, although intrablock transesterification side reactions occurred only within the PPDL section. The same effect was demonstrated across a range of relative molar equivalents of monomers, and the generality of the approach was further demonstrated with the copolymerization of PDL with other εSL monomers. Finally, the copolymerization of PDL with an alkene-functionalized εSL was shown to produce one-pot PDL block-like copolymers that could undergo postpolymerization modification by thiol-ene addition to produce block copolymers with a range of characteristics in a simple procedure.

Highly branched poly(N-isopropyl acrylamide-co-1,2 propandiol-3-methacrylate)s with imidazole end groups and containing anthramethyl methacrylate (AMMA) were prepared. The branch points were produced by incorporating a styryl dithioate ester (a RAFT monomer). The inclusion of AMMA ensures that the polymers fluoresce in the blue region so that they can be visualized in cells in culture. The feed composition was designed to provide lower critical solution temperatures (LCST) between 30 and 37 uC, and therefore the polymers are above the LCST at the usual temperature for culture of human cells. Inclusion of 1,2 propandiol-3-methacrylate (GMA) results in the formation of stable aggregates above the LCST rather than flocculated masses of polymer, and these colloidally stable sub-micron particles can undergo phagocytosis into human dermal fibroblasts. The phagocytosis is temperature dependant and does not occur below the LCST (at 30 uC) when the polymers are in the open-chain fully solvated and non-aggregated state.

We describe the first example of particulate materials that can detach cultured cells and then release them intact in a temperature controlled manner. Topologically open microgels composed of water swollen highly branched polymers prepared from poly(N-isopropylacrylamide) (PNIPAM) were modified with a cell-adhesive peptide (GRGDS) to produce particles for gently detaching and then transferring cultured cells to new substrates. The particles bind to cell surface integrins on both dermal fibroblasts and endothelial cells and at temperatures above the lower critical solution temperature (34 C) remove cells from their normal culture substrates. Brief (45 min) cooling of the resultant particle-cell dispersion to beneath 34 C releases the cells to grow on new substrates. This avoids the need for trypsinisation to detach cells or centrifugation to collect cells post-detachment and offers a flexible approach to cell detachment and transport which is compatible with normal cell culture methodologies.