Clickable Stars by Combination of AROP and Aqueous AGET ATRP

Copper Nanodrugs with Controlled Morphologies through Aqueous Atom Transfer Radical Polymerization

Copper (Cu) nanodrugs can be facilely prepared through atom transfer radical polymerization (ATRP) in an aqueous medium. However, it is difficult to control the morphology of Cu nanodrugs and thereby optimize their anticancer activity. In this work, aqueous ATRP was combined with polymerization-induced self-assembly (PISA) to prepare Cu nanodrugs with various morphologies. We mapped the relationship between polymerization condition and product morphology in which each morphology shows a wide preparation window. Decreasing the reaction temperature and feeding more Cu catalysts can improve the mobility of chains, facilitating the morphology evolution from sphere to other high-order morphologies. The resultant Cu nanodrugs with high monomer conversion and high Cu loading efficiency could be easily taken by cancer cells, showing excellent anticancer efficacy in vitro. This work proposed a potential strategy to prepare Cu nanodrugs with a specific morphology in batches, providing the method to optimize the anticancer efficacy through morphology control.

Copper Nanodrugs by Atom Transfer Radical Polymerization

In this study, some copper catalysts used for atom transfer radical polymerization (ATRP) were explored as efficient anti-tumor agents. The aqueous solution of copper-containing nanoparticles with uniform spheric morphology was in situ prepared through a copper-catalyzed activator generated by electron transfer (AGET) ATRP in water. Nanoparticles were then directly injected into tumor-bearing mice for antitumor chemotherapy. The copper nanodrugs had prolonged blood circulation time and enhanced accumulation at tumor sites, thus showing potent antitumor activity. This work provides a novel strategy for precise and large-scale preparation of copper nanodrugs with high antitumor activity.

Multiarm Star-Shaped Polydimethylsiloxanes with a Dendritic Branching Center

New multiarm stars have been synthesized based on polylithium derivatives of high-generation carbosilane dendrimers. In the synthesis of multiarm stars based on the eighth-generation dendrimer, steric hindrances were observed even during the synthesis of a polylithium initiator. Subsequently, this led to chain transfer reactions between growing arms, as well as other side effects. As a result, dense nanogel formations with a higher tendency of ordering than in classical objects of this type were isolated from the reaction mixture. The study of the rheology of multiarm stars based on sixth-generation dendrimers made it possible to determine the activation energies of viscous flow in these objects, which makes it possible to consider them as objects with a macromolecular nature and a reptation flow mechanism.

Anionic Polymerization of Styrene and 1,3-Butadiene in the Presence of Phosphazene Superbases

The anionic polymerization of styrene and 1,3-butadiene in the presence of phosphazene bases (t-BuP₄, t-BuP₂ and t-BuP₁), in benzene at room temperature, was studied. When t-BuP₁ was used, the polymerization proceeded in a controlled manner, whereas the obtained homopolymers exhibited the desired molecular weights and narrow polydispersity (Ð < 1.05). In the case of t-BuP₂, homopolymers with higher than the theoretical molecular weights and relatively low polydispersity were obtained. On the other hand, in the presence of t-BuP₄, the polymerization of styrene was uncontrolled due to the high reactivity of the formed carbanion. The kinetic studies from the polymerization of both monomers showed that the reaction rate follows the order of [t-BuP₄]/[sec-BuLi] >>> [t-BuP₂]/[sec-BuLi] >> [t-BuP₁]/[sec-BuLi] > sec-BuLi. Furthermore, the addition of t-BuP₂ and t-BuP₁ prior the polymerization of 1,3-butadiene allowed the synthesis of polybutadiene with a high 1,2-microstructure (~45 wt %), due to the delocalization of the negative charge. Finally, the one pot synthesis of well-defined polyester-based copolymers [PS-b-PCL and PS-b-PLLA, PS: Polystyrene, PCL: Poly(ε-caprolactone) and PLLA: Poly(L-lactide)], with predictable molecular weights and a narrow molecular weight distribution (Ð < 1.2), was achieved by sequential copolymerization in the presence of t-BuP₂ and t-BuP₁.

Star Polymers

Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

Injectable camptothecin conjugated hydrogels with simultaneous drug release and degradation

Novel injectable camptothecin conjugated hydrogels with simultaneous drug release and degradation properties were prepared, which show significant cytotoxicity to HepG2 cells, and could be a potential candidate for intratumor drug delivery.

Construction of d-α-tocopheryl polyethylene glycol succinate/PEO core–shell nanofibers on a blood-contacting surface to reduce the hemolysis of preserved erythrocytes

The TPGS released from the electrospun SEBS protected the preserved red blood cells from oxidative damage, resulting in low hemolysis and mechanical fragility.

Carboxymethylpullulan promoted Cu2O-catalyzed Huisgen-click reaction

Cu₂O/CMP has been developed as a highly efficient catalytic system for Huisgen-click reaction in water at 60 °C.

Facile fabrication of reduction-responsive nanocarriers for controlled drug release

An amphiphilic multiblock poly(ether–ester) containing multiple thiols was facilely synthesized by “one-pot” polycondensation, and was used to prepare reduction-responsive core-crosslinked micelles for controlled drug release.

Azobenzene-Functionalised Core Cross-Linked Star Polymers and their Host–Guest Interactions

Water-soluble poly(2-hydroxyethyl acrylate) (PHEA)-based core cross-linked star polymers were efficiently synthesised with high macroinitiator-to-star-conversion (>95 %) in a one-pot system via single electron transfer-living radical polymerisation. The star polymers display excellent water solubility and the pendant hydroxyl groups provide a platform for facile post-functionalisation with various molecules. In demonstrating this, a photo-isomerisable molecule, 4-(phenylazo)benzoic acid was conjugated onto the preformed stars through partial esterification of the available hydroxyl groups (5–20 %). The azobenzene functionalised stars were subsequently employed to form reversible inclusion complexes with α-cyclodextrin.