Forcing single-chain nanoparticle collapse through hydrophobic solvent interactions in comb copolymers

We demonstrate that we can tune the chain collapse of comb copolymers into single-chain nanoparticles upon UV irradiation through solvency control.

Advances in the Phototriggered Synthesis of Single-Chain Polymer Nanoparticles

Clean use of photons from light to activate chemical reactions offers many possibilities in different fields, from chemistry and biology to materials science and medicine. This review article describes the advances carried out in last decades toward the phototriggered synthesis of single-chain polymer nanoparticles (SCNPs) as soft nanomaterials with promising applications in enzyme-mimicking catalysis and nanomedicine, among other different uses. First, we summarize some different strategies developed to synthesize SCNPs based on photoactivated intrachain homocoupling, phototriggered intrachain heterocoupling and photogenerated collapse induced by an external cross-linker. Next, we comprehensively review the emergent topic of photoactivated multifolding applied to SCNP construction. Finally, we conclude by summarizing recent strategies towards phototriggered disassembly of SCNPs.

Anti-Stokes Stress Sensing: Mechanochemical Activation of Triplet-Triplet Annihilation Photon Upconversion

The development of methods to detect damage in macromolecular materials is of paramount importance to understand their mechanical failure and the structure-property relationships of polymers. Mechanofluorophores are useful and sensitive molecular motifs for this purpose. However, to date, tailoring of their optical properties remains challenging and correlating emission intensity to force induced material damage and the respective events on the molecular level is complicated by intrinsic limitations of fluorescence and its detection techniques. Now, this is tackled by developing the first stress-sensing motif that relies on photon upconversion. By combining the Diels-Alder adduct of a π-extended anthracene with the porphyrin-based triplet sensitizer PtOEP in polymers, triplet-triplet annihilation photon upconversion of green to blue light is mechanochemically activated in solution as well as in the solid state.

Supramolecular Single-Chain Polymeric Nanoparticles

Nature has unparalleled control over the conformation and dynamics of its folded macromolecular structures. Nature’s ability to arrange amino acids into a precise spatial organization by way of folding allows proteins to fulfill specific functions in an extremely efficient manner. Chemists and materials scientists have used the delicate structure–function relationships observed in proteins to elucidate nature’s design principles. These insights have led to the development of various revolutionary macromolecular architectures, mimicking the structural features of proteins. In this review, we focus on the folding of single polymer chains into well-defined nanoparticles using supramolecular interactions and their possible use as enzyme mimics.