Rational synthesis of novel biocompatible thermoresponsive block copolymer worm gels

Abstract

Judicious control over the mean degree of polymerization of each block in a amphiphilic diblock copolymer ensures that the corresponding worm gel exhibits thermoreversible (de)gelation behavior, as judged by TEM, SAXS and rheology studies.

Investigation of the Thermogelation of a Promising Biocompatible ABC Triblock Terpolymer and Its Comparison with Pluronic F127

“…Additionally, lower polymer concentrations often correspond to improved injectability, and the TRG formed has higher porosity, which is critical for the transport of nutrients. To meet this need, several studies have reported TRGs with low CGC based on diblock copolymers such as − (i) thermoresponsive worm gels by Armes’ group − (at 10% w/w and 21 °C) and (ii) double hydrophobic micellar gels in water/ethanol mixtures by Hoogenboom et al (at 1% w/w) . TRGs with low CGC based on ABC triblock terpolymers have also been reported, − including (i) a hydrogel based on a triblock terpolymer with two discrete cores by Zhou et al (at 5% w/w and 42 °C), , (ii) reactive oxygen species (ROS)-degradable polymer by Gupta et al.…”

Synthesis of Thermoresponsive Diblock Copolymer Nano-Objects via RAFT Aqueous Emulsion Polymerization of Hydroxybutyl Methacrylate

“…There are numerous examples of thermoresponsive diblock copolymer nano-objects in the PISA literature. ,,− ,− ,,,,− To examine whether PEG 45 –PHBMA 20 nano-objects also exhibit thermally-induced changes in morphology, TEM studies were performed for 0.1% w/w aqueous dispersions after drying at 25, 58, 65, or 75 °C. Unlike previously reported temperature-dependent studies on PHBA-based diblock copolymers, ,, the PEG 45 –PHBMA 20 nano-objects studied herein do not require covalent stabilization prior to their visualization by TEM.…”

“…It is well-known that polymerization-induced self-assembly (PISA) enables the convenient and efficient preparation of a wide range of diblock copolymer nano-objects in the form of concentrated dispersions. − In the case of aqueous PISA formulations, if the vinyl monomer used to grow the hydrophobic second block is water-miscible, this corresponds to an aqueous dispersion polymerization. ,,,− On the other hand, if the monomer is water-immisciblewhich is much more commonthis corresponds to an aqueous emulsion polymerization. − In the PISA literature, there has been substantial interest in the rational design of aqueous dispersions of thermoresponsive shape-shifting diblock copolymer nano-objects over the past decade. ,− In practice, such nano-objects are invariably prepared via RAFT aqueous dispersion polymerization. ,− This is because water-miscible vinyl monomers such as 2-hydroxypropyl methacrylate (HPMA), ,− 4-hydroxybutyl acrylate (HBA), ,, N -isopropylacrylamide, , or 2-methoxyethyl acrylate , produce homopolymers that are only weakly hydrophobic. In particular, their degree of (partial) hydration is temperature-dependent, which affects the relative volume fraction of such hydrophobic blocks. , This induces a subtle change in the fractional packing parameter P , ,…”

Aldehyde-functional thermoresponsive diblock copolymer worm gels exhibit strong mucoadhesion

“…25,26 In particular, the reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) provides access to thermoresponsive worms that exhibit a worm-to-sphere transition on cooling to subambient temperature. 27,[32][33][34][35] This morphological transition is accompanied by degelation and is reversible. 36 This is important in the context of potential cell biology applications because it allows the media to be sterilized via ultraltration and enables the cells to be readily harvested aer cell culture studies.…”