The Role of Chemically Innocent Polyanions in Active, Chemically Fueled Complex Coacervate Droplets.

Complex coacervation describes the liquid-liquid phase separation of oppositely charged polymers. Active coacervates are droplets in which one of the electrolyte's affinity is regulated by chemical reactions. These droplets are particularly interesting because they are tightly regulated by reaction kinetics. For example, they serve as a model for membraneless organelles that are also often regulated by biochemical transformations such as post-translational modifications. They are also a great protocell model or could be used to synthesize life-they spontaneously emerge in response to reagents, compete, and decay when all nutrients have been consumed. However, the role of the unreactive building blocks, e.g., the polymeric compounds, is poorly understood. Here, we show the important role of the chemically innocent, unreactive polyanion of our chemically fueled coacervation droplets. We show that the polyanion drastically influences the resulting droplets' life cycle without influencing the chemical reaction cycle-either they are very dynamic or have a delayed dissolution. Additionally, we derive a mechanistic understanding of our observations and show how additives and rational polymer design help to create the desired coacervate emulsion life cycles.

Correction to "Cytocompatible Triblock Copolymers with Controlled Microstructure Enabling Orthogonally Functionalized Bio-polymer Conjugates".

[This corrects the article DOI: 10.1021/acs.macromol.3c02238.].

Cytocompatible Hydrogels with Tunable Mechanical Strength and Adjustable Swelling Properties through Photo-Cross-Linking of Poly(vinylphosphonates).

Herein, the synthesis, characterization, and application of a novel synthetic hydrogel based on the photoinitiated cross-linking of poly(vinylphosphonates) is presented. First, statistical copolymers with adjustable ratios of the monomers diallyl vinylphosphonate (DAlVP) and diethyl vinylphosphonate (DEVP), as well as different molecular weights, were obtained via rare earth metal-mediated group-transfer polymerization (REM-GTP) while maintaining narrow polydispersities. The copolymers were cross-linked by applying photoinitiated thiol-ene click chemistry (λ = 365 nm). The network formation was monitored via oscillatory rheology coupled with UV-irradiation, revealing the high spatiotemporal control of the reaction. Moreover, the equilibrium storage moduli of poly(vinylphosphonate)-based hydrogels increased with a growing number of DAlVP units and upon application of a different cross-linker, which was additionally confirmed by nanoindentation experiments. In contrast, the water uptake of hydrogels decreased with higher DAlVP amounts in the corresponding hydrogels due to lower chain mobility and an overall increase in the hydrophobicity of the samples. Upon successful functionalization of P(DEVP-stat-DAlVP) copolymers with sodium 3-mercaptopropane-1-sulfonate, as indicated via 1H DOSY NMR, the respective cross-linked materials displayed a remarkable increase in the water uptake; thus, presenting highly hydrophilic gels with an apparent interplay between water uptake, cross-linking density, and functionalization degree. Finally, the purified hydrogels showed cytocompatibility and enabled cell adhesion of human umbilical artery smooth muscle cells (HUASMCs) after direct seeding. The materials further allowed the adhesion and growth of an endothelial layer, triggered no pro-inflammatory response as evidenced by cytokine release of M0 macrophages, and exhibited antibacterial properties toward S. aureus and E. coli.

A graft-to strategy of poly(vinylphosphonates) on dopazide-coated gold nanoparticles using in situ catalyst activation.

A modular synthetic pathway for poly(diethyl vinylphosphonates) grafting-to gold nanoparticles is presented. Utilising an azide-dopamine derivative as nanoparticle coating agent, alkyne-azide click conditions were used to covalently tether the polymer to gold nanoparticles leading to stable and well distributed colloids for different applications.

Allyl group-containing polyvinylphosphonates as a flexible platform for the selective introduction of functional groups via polymer-analogous transformations.

Polyvinylphosphonates are highly promising candidates for (bio)medical applications as they exhibit a tunable lower critical solution temperature, high biocompatibility of homo- and copolymers, and a broad foundation for post-synthetic modifications. In this work we explored polymer-analogous transformations with statistical polyvinylphosphonates comprising diethyl vinylphosphonate (DEVP) and diallyl vinylphosphonate (DAlVP). The C[double bond, length as m-dash]C double bonds were used as a starting point for a cascade of organic transformations. Initially, the reactive moieties were successfully introduced via bromination, epoxidations with OXONE and mCPBA, or thiol-ene click chemistry with methyl thioglycolate (6). The obtained substrates were then employed in a variety of consecutive reactions depending on the introduced functional motif: (1) the brominated substrates were converted with sodium azide to enable the copper-mediated alkyne-azide coupling with phenylacetylene (1). (2) The epoxides were reacted with sodium azide for an alkyne-azide click coupling with 1 as well as small nucleophilic compounds (phenol (2), benzylamine (3), and 4-amino-2,1,3-benzothiadiazol (4)). Afterwards the non-converted allyl groups were reacted with thiochloesterol (5) to form complex polymer conjugates. (3) An acid-labile hydrazone-linked conjugate was formed in a two-step approach. The polymeric substrates were characterized by NMR, FTIR, and UV/Vis spectroscopy as well as elemental analysis and gel permeation chromatography to monitor the structural changes of the polymeric substrates and to prove the success of these modification approaches.