Synthesis of main chain sulfur-containing aliphatic polycarbonates by organocatalytic ring-opening polymerization of macrocyclic carbonates

The first application of organocatalysts is reported to achieve highly active and living ring-opening polymerization (ROP) of thioether-based macrocyclic carbonates for preparing well-defined main chain thioether functional APCs.

Transiently thermoresponsive polymers and their applications in biomedicine

The focus of this review is on the class of transiently thermoresponsive polymers. These polymers are thermoresponsive, but gradually lose this property upon chemical transformation - often a hydrolysis reaction - in the polymer side chain or backbone. An overview of the different approaches used for the design of these polymers along with their physicochemical properties is given. Their amphiphilic properties and degradability into fully soluble compounds make this class of responsive polymers attractive for drug delivery and tissue engineering applications. Examples of these are also provided in this review.

Synthesis of aliphatic polycarbonates with a tuneable thermal response

The synthesis of aliphatic polycarbonates with a tuneable thermal-response is reported by a ‘click-and mix’ approach.

Facile construction of near-monodisperse and dual responsive polycarbonate mixed micelles with the ability of pH-induced charge reversal for intracellular delivery of antitumor drugs

A mixed strategy was used to construct size-adjustable, pH and redox dual-responsive, near-monodisperse and charge-conversional core-shell polycarbonate carriers. First, two kinds of random polycarbonates (PC(Arss-N2CH₃)) with different ratios of hydrophobic disulfide (Arss) and hydrophilic dimethylamine functional groups (N2CH₃) (relatively hydrophobic polycarbonate (BPC) with more disulfide groups and relatively hydrophilic polycarbonate (LPC) with more dimethylamine groups) were used to construct near-monodisperse core micelles in pH 7.4 PBS. Then, a negatively charged shell polymer, poly(ethylene glycol)-b-1,2-dicarboxylic-cyclohexene anhydride modified amino polycarbonate (PEG-PCDCA), bearing acid-labile β-carboxylic amides, was added to the core micelle solution to get the desired mixed micelle. The assembly process, pH induced charge-reversal, and dual-response abilities of the resultant mixed micelles were thoroughly studied using zeta potential and dynamic light scattering (DLS). Two model drugs, Nile red (NR) and doxorubicin (DOX), were successfully loaded into the micelle and could be released in response to dithiothreitol (DTT) and acidic conditions. Confocal microscopy indicated that the micelle system could achieve effective cellular uptake and DOX release in Hela cells. Moreover, the blank micelle and the drug-loaded mixed micelle showed slight and great cytotoxicity against Hela cells, respectively, indicating their significant potential in cancer therapy.

Core functionalization of semi-crystalline polymeric cylindrical nanoparticles using photo-initiated thiol-ene radical reactions

Sequential ring-opening and reversible addition-fragmentation chain transfer (RAFT) polymerization was used to form a triblock copolymer of tetrahydropyran acrylate (THPA), 5-methyl-5-allyloxycarbonyl-1,3-dioxan-2-one (MAC) and l-lactide. Concurrent deprotection of the THPA block and crystallization-driven self-assembly (CDSA) was undertaken and allowed for the formation of cylindrical micelles bearing allyl handles in a short outer core segment. These handles were further functionalized by different thiols using photo-initiated thiol-ene radical reactions to demonstrate that the incorporation of an amorphous PMAC block within the core does not disrupt CDSA and can be used to load the cylindrical nanoparticles with cargo.

Self-assembled thermosensitive nanoparticles based on oligoethylene glycol dendron conjugated doxorubicin: preparation, and efficient delivery of free doxorubicin

An amphiphilic dendron–drug conjugate was synthesized via oligoethylene glycol (OEG) dendrons coupled with anticancer drug doxorubicin (DOX).