Polymer Nanofibers Exhibiting Remarkable Activity in Driving the Living Polymerization under Visible Light and Reusability.

Visible light-driving syntheses have emerged as a powerful tool for organic synthesis and for the preparation of macromolecules under mild and environmentally benign conditions. However, precious but nonreusable photosensitizers or photocatalysts are often required to activate the reaction, limiting its practicality. Here, it is reported that poly(1,4-diphenylbutadiyne) (PDPB) nanofibers exhibit remarkable activity in driving the living free radical polymerization under visible light. Moreover, PDPB nanofibers are very stable under irradiation of visible light and can be reused without appreciable loss of activity even after repeated cycling. The nanofiber will be a promising photocatalyst with excellent reusability and stability for the reactions driven by visible light.

Photothermal Therapy Nanomaterials Boosting Transformation of Fe(III) into Fe(II) in Tumor Cells for Highly Improving Chemodynamic Therapy.

Chemodynamic therapy based on Fe2+-catalyzed Fenton reaction holds great promise in cancer treatment. However, low-produced hydroxyl radicals in tumor cells constitute its severe challenges because of the fact that Fe2+ with high catalytic activity could be easily oxidized into Fe3+ with low catalytic activity, greatly lowering Fenton reaction efficacy. Here, we codeliver CuS with the iron-containing prodrug into tumor cells. In tumor cells, the overproduced esterase could cleave the phenolic ester bond in the prodrug to release Fe2+, activating Fenton reaction to produce the hydroxyl radical. Meanwhile, CuS could act as a nanocatalyst for continuously catalyzing the regeneration of high-active Fe2+ from low-active Fe3+ to produce enough hydroxyl radicals to efficiently kill tumor cells as well as a photothermal therapy agent for generating hyperthermia for thermal ablation of tumor cells upon NIR irradiation. The results have exhibited that the approach of photothermal therapy nanomaterials boosting transformation of Fe3+ into Fe2+ in tumor cells can highly improve Fenton reaction for efficient chemodynamic therapy. This strategy was demonstrated to have an excellent antitumor activity both in vitro and in vivo, which provides an innovative perspective to Fenton reaction-based chemodynamic therapy.

Synthesis of polymers with on-demand sequence structures via dually switchable and interconvertible polymerizations.

The synthesis of polymers with on-demand sequence structures is very important not only for academic researchers but also for industry. However, despite the existing polymerization techniques, it is still difficult to achieve copolymer chains with on-demand sequence structures. Here we report a dually switchable and controlled interconvertible polymerization system; in this system, two distinct orthogonal polymerizations can be selectively switched ON/OFF independent of each other and they can be interconverted promptly and quantitatively according to external stimuli. Thus, the external stimuli can manipulate the insertion of distinct monomers into the resulting copolymer chains temporally, spatially, and orthogonally, allowing the on-demand precise arrangement of sequence structures in the resulting polymers. This dually switchable and interconvertible polymerization system provides a powerful tool for synthesizing materials that are not accessible by other polymerization methods.

A RAFT/MADIX method finely regulating the copolymerization of ethylene and polar vinyl monomers under mild conditions.

A RAFT/MADIX method can not only copolymerize ethylene with a diverse range of functionally polar monomers, but can also easily tune the polar composition and the polar monomer distribution along the produced copolymer chains. This highly versatile RAFT/MADIX copolymerization platform provides access to a diverse range of polyethylene materials.