Visible light photoflow synthesis of a Cu(ii) single-chain polymer nanoparticle catalyst

We herein pioneer the visible light (λ max = 410 nm) mediated flow synthesis of catalytically active single-chain nanoparticles (SCNPs). Our design approach is based on a copolymer of poly(ethylene glycol) methyl ether methacrylate and a photocleavable 2-((((2-nitrobenzyl)oxy)carbonyl)amino)ethyl methacrylate monomer which can liberate amine groups upon visible light irradiation, allowing for single-chain collapse via the complexation of Cu(ii) ions. We initially demonstrate the successful applicability of our design approach for the batch photochemical synthesis of Cu(ii) SCNPs and transfer the concept to photoflow conditions, enabling, for the first time, the continuous production of functional SCNPs. Critically, we explore their ability to function as a photocatalyst for the cleavage of carbon-carbon single and double bonds on the examples of xanthene-9-carboxylic acid and oleic acid, demonstrating the advantageous effect SCNPs can provide over analogous small molecule catalysts.

Recent Advances on Fabrication of Polymeric Composites Based on Multicomponent Reactions for Bioimaging and Environmental Pollutant Removal

As the core of polymer chemistry, manufacture of functional polymers is one of research hotspots over the past several decades. Various polymers are developed for diverse applications due to their tunable structures and unique properties. However, traditional step-by-step preparation strategies inevitably involve some problems, such as separation, purification, and time-consuming. The multicomponent reactions (MCRs) are emerging as environmentally benign synthetic strategies to construct multifunctional polymers or composites with pendant groups and designed structures because of their features, such as efficient, fast, green, and atom economy. This mini review summarizes the latest advances about fabrication of multifunctional fluorescent polymers or adsorptive polymeric composites through different MCRs, including Kabachnik-Fields reaction, Biginelli reaction, mercaptoacetic acid locking imine reaction, Debus-Radziszewski reaction, and Mannich reaction. The potential applications of these polymeric composites in biomedical and environmental remediation are also highlighted. It is expected that this mini-review will promote the development preparation and applications of functional polymers through MCRs.

Ring opening polymerization of α-amino acids: advances in synthesis, architecture and applications of polypeptides and their hybrids

This review provides a comprehensive overview of the latest advances in the synthesis, architectural design and biomedical applications of polypeptides and their hybrids.

Self-crosslinking assemblies with tunable nanostructures from photoresponsive polypeptoid-based block copolymers

A series of reversible crosslinking assemblies with tunable morphologies are obtained from a new family of photoresponsive polypeptoid-based diblock copolymers.

UV-responsive cyclic peptide progelator bioinks

We describe cyclic peptide progelators which cleave in response to UV light to generate linearized peptides which then self-assemble into gel networks. Cyclic peptide progelators were synthesized, where the peptides were sterically constrained, but upon UV irradiation, predictable cleavage products were generated. Amino acid sequences and formulation conditions were altered to tune the mechanical properties of the resulting gels. Characterization of the resulting morphologies and chemistry was achieved through liquid phase and standard TEM methods, combined with matrix assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS).

Surfactant Pyrolysis-Guided in Situ Fabrication of Primary Amine-Rich Ordered Mesoporous Phenolic Resin Displaying Efficient Heavy Metal Removal

A unique strategy for the direct preparation of primary amine-functionalized ordered mesoporous phenolic resin (NH₂-MPRN) was presented. The essence of our approach avoided the side reactions in the m-nitrophenol-formaldehyde resol synthesis using m-nitrophenol and formaldehyde as the monomers. Importantly, these resols can efficiently assemble with triblock copolymer F127 to form a mesostructured composite. The final prolysis treatment removed the F127 template to produce ordered mesopores, and meanwhile, the accompanying reductive gas in situ transferred the nitro groups to primary amines. Notably, the obtained NH₂-MPRN material delivered fast toxic hexavalent chromium sorption kinetics with high uptake capacity and selectivity due to a mesoporous structure, high amine availability, and a hydrophobic surface. Interestingly, almost all of adsorbed chromium species existed as low-toxic trivalent chromium in the resin owing to the cooperative detoxification process by the neighboring primary amines and phenolic hydroxyl groups. Also, it showed the reversible detoxification for at least five times.

Protein diffusion from microwells with contrasting hydrogel domains

Understanding and controlling molecular transport in hydrogel materials is important for biomedical tools, including engineered tissues and drug delivery, as well as life sciences tools for single-cell analysis. Here, we scrutinize the ability of microwells-micromolded in hydrogel slabs-to compartmentalize lysate from single cells. We consider both (i) microwells that are "open" to a large fluid (i.e., liquid) reservoir and (ii) microwells that are "closed," having been capped with either a slab of high-density polyacrylamide gel or an impermeable glass slide. We use numerical modeling to gain insight into the sensitivity of time-dependent protein concentration distributions on hydrogel partition and protein diffusion coefficients and open and closed microwell configurations. We are primarily concerned with diffusion-driven protein loss from the microwell cavity. Even for closed microwells, confocal fluorescence microscopy reports that a fluid (i.e., liquid) film forms between the hydrogel slabs (median thickness of 1.7 μm). Proteins diffuse from the microwells and into the fluid (i.e., liquid) layer, yet concentration distributions are sensitive to the lid layer partition coefficients and the protein diffusion coefficient. The application of a glass lid or a dense hydrogel retains protein in the microwell, increasing the protein solute concentration in the microwell by ∼7-fold for the first 15 s. Using triggered release of Protein G from microparticles, we validate our simulations by characterizing protein diffusion in a microwell capped with a high-density polyacrylamide gel lid (p > 0.05, Kolmogorov-Smirnov test). Here, we establish and validate a numerical model useful for understanding protein transport in and losses from a hydrogel microwell across a range of boundary conditions.

Protection strategies for directionally-controlled synthesis of previously inaccessible metal–organic polyhedra (MOPs): the cases of carboxylate- and amino-functionalised Rh(ii)-MOPs

Herein we report that strategic use of protecting groups in coordination reactions enables directional inhibition that leads to synthesis of metal–organic polyhedra (MOPs) highly functionalized with carboxylic acid and amine groups.

Synthesis of Multifunctional Homopolymers through Using Thiazolidine Chemistry and Post-Polymerization Modification

Multifunctional homopolymers, defined here as polymers that contain multiple reactive functional groups per repeat unit, are versatile scaffolds for preparing complex macromolecules via post-polymerization modification. However, there are limited methods for preparing multifunctional homopolymers that contain more than one nucleophilic site per repeat unit. Herein, a strategy to synthesize a multifunctional homopolymer using thiazolidine chemistry is demonstrated. Controlled radical polymerization of a thiazolidine-containing acrylamido monomer allows for the synthesis of a polymer with pendent latent nucleophiles. Ring-opening of the thiazolidine affords a homopolymer with two side-chain reactive sites, an amine and a thiol. One-pot functionalization via disulfide formation and acyl substitution is performed to introduce two distinct groups in each repeat unit.