PEG-functionalized aliphatic polycarbonate brushes with self-polishing dynamic antifouling properties

Hydrophilic antifouling polymers provide excellent antifouling effects under usual short-term use conditions, but the long-term accumulation of contaminants causes them to lose their antifouling properties. To overcome this drawback, surface-initiated ring-opening graft polymerization (SI-ROP) was performed on the surface of the material by applying the cyclic carbide monomer 4'-(fluorosulfonyl)benzyl-5-methyl-2-oxo-1,3-dioxane-5-carboxylate (FMC), which contains a sulfonylfluoride group on the side chain, followed by a "sulfur(IV)-fluorine exchange" (SuFEx) post click modification reaction to link the hydrophilic polyethylene glycol (PEG) to the polyFMC (PFMC) brush, and a novel antifouling strategy for self-polishing dynamic antifouling surfaces was developed. The experimental results showed that the antifouling surface could effectively prevent the adsorption of proteins such as bovine serum albumin (BSA, ∼96.4%), fibrinogen (Fg, ∼87.8%) and lysozyme (Lyz ∼69.4%) as well as the adhesion of microorganisms such as the bacteria Staphylococcus aureus (S. aureus) (∼87.5%) and HeLa cells (∼67.2%). Moreover, the enzymatically self-polished surface still has excellent antifouling properties. Therefore, this modification method has potential applications in the field of biosensors and novel antifouling materials.

Sulfonyl fluorides as targets and substrates in the development of new synthetic methods

The advent of sulfur(VI)-fluoride exchange (SuFEx) processes as transformations with click-like reactivity has invigorated research into electrophilic species featuring a sulfur-fluorine bond. Among these, sulfonyl fluorides have emerged as the workhorse functional group, with diverse applications being reported. Sulfonyl fluorides are used as electrophilic warheads by both medicinal chemists and chemical biologists. The balance of reactivity and stability that is so attractive for these applications, particularly the resistance of sulfonyl fluorides to hydrolysis under physiological conditions, has provided opportunities for synthetic chemists. New synthetic approaches that start with sulfur-containing substrates include the activation of sulfonamides using pyrilium salts, the deoxygenation of sulfonic acids, and the electrochemical oxidation of thiols. Employing non-sulfur-containing substrates has led to the development of transition-metal-catalysed processes based on palladium, copper and nickel, as well as the use of SO₂F₂ gas as an electrophilic hub. Selectively manipulating molecules that already contain a sulfonyl fluoride group has also proved to be a popular tactic, with metal-catalysed processes again at the fore. Finally, coaxing sulfonyl fluorides to engage with nucleophiles, when required, and under suitable reaction conditions, has led to new activation methods. This Review provides an overview of the challenges in the efficient synthesis and manipulation of these intriguing functional groups.

A novel Y-shaped photoiniferter used for the construction of polydimethylsiloxane surfaces with antibacterial and antifouling properties

The simultaneous introduction of two new functionalities into the same polymeric substrate under mild reaction conditions is an interesting and important topic. Herein, dual-functional polydimethylsiloxane (PDMS) surfaces with antibacterial and antifouling properties were conveniently developed via a novel Y-shaped asymmetric dual-functional photoiniferter (Y-iniferter). The Y-iniferter was initially immobilized onto the PDMS surface by radical coupling under visible light irradiation. Afterwards, poly(2-hydroxyethyl methacrylate) (PHEMA) brushes and antibacterial ionic liquid (IL) fragments were simultaneously immobilized on the Y-iniferter-modified PDMS surfaces by combining the sulfur(VI)-fluoride exchange (SuFEx) click reaction and UV-photoinitiated polymerization. Experiments using E. coli as a model bacterium demonstrated that the modified PDMS surfaces had both the expected antibacterial properties of the IL fragments and the excellent antifouling properties of PHEMA brushes. Furthermore, the cytotoxicity of the modified PDMS surfaces to L929 cells was examined in vitro with a CCK-8 assay, which showed that the modified surfaces maintained excellent cytocompatibility. Briefly, this strategy of constructing an antibacterial and antifouling PDMS surface has the advantages of simplicity and convenience and might inspire the construction of diverse dual-functional surfaces by utilizing PDMS more effectively.

Side-Chain Type Polysulfates: Their Synthesis, AIE Properties and Applications for p-Nitrophenol Detection in Water

Two small molecular monomers, ph-TPE and ph-TPE-CN, and their homopolymers Poly (ph-TPE) and Poly (ph-TPE-CN) containing tetra phenylethylene and sulfate structures, were synthesized by a sulfur (VI) fluorine exchange click reaction (SuFEx) and radical polymerization. All the monomers and polymers exhibit a typical aggregation-induced emission (AIE) effect both in the solid state and aggregated state. Moreover, based on the intermolecular charge transfer (ICT) effect between the tetra phenylethylene chromophore and p-nitrophenol, both polymers could be used for the selective detection of p-nitrophenol. The detection limit and reactivity coefficient of Poly (ph-TPE) are 0.081 μM and 5.15×10⁴  M^-1 , respectively, whereas the detection limit and reactivity coefficient of Poly (ph-TPE-CN) are 0.077 μM and 1.81×10⁴  M^-1 , respectively. This can be attributed to the greater sensitivity of Poly (ph-TPE-CN) to p-nitrophenol than that of Poly (ph-TPE). This work provides a new methodology for the preparation and broadening application of side-chain type AIE-active polysulfate fluorescent probes.

Preparation of AAEK-functionalized cellulose film with antibacterial and anti-adhesion activities

Bacterial adhesion infection caused by medical materials in clinical application has become a serious threat, and it urgently needs new strategies to deal with these clinical challenges. The purpose of this study is to explore the effectiveness of surface-decorated aryl (β-amino) ethyl ketones (AAEK), a promising sorting enzyme A (SrtA) inhibitor of Staphylococcus aureus, to improve the anti-adhesion ability of biomaterials. AAEK was covalently grafted onto cellulose films (CF) via copper-catalyzed azide-alkyne 1, 3-dipolar cycloaddition click reaction. The data of contact angle measurements, ATR-FTIR and XPS proved the successful covalent attachment of AAEK-CF, and the antimicrobial efficacy of AAEK coating was assessed by CFUs, crystal violet staining, scanning electron microscopy and Living/Dead bacteria staining assay. The results illustrated that AAEK-CF exhibited excellent anti-adhesion ability to Staphylococcus aureus, and significantly reduced the number of bacteria adhering to the film. More importantly, AAEK-CF could hinder the formation of bacterial biofilm. Furthermore, AAEK-CF indicated no cytotoxicity to mammalian cells, and the cells could grow normally on the modified surface. Hence, our present work demonstrated that the grafting of the SrtA inhibitor-AAEK onto cellulose films enabled to combat bacterial biofilm formation in biomedical applications.

A Comprehensive Review of the Covalent Immobilization of Biomolecules onto Electrospun Nanofibers

Biomolecule immobilization has attracted the attention of various fields such as fine chemistry and biomedicine for their use in several applications such as wastewater, immunosensors, biofuels, et cetera. The performance of immobilized biomolecules depends on the substrate and the immobilization method utilized. Electrospun nanofibers act as an excellent substrate for immobilization due to their large surface area to volume ratio and interconnectivity. While biomolecules can be immobilized using adsorption and encapsulation, covalent immobilization offers a way to permanently fix the material to the fiber surface resulting in high efficiency, good specificity, and excellent stability. This review aims to highlight the various covalent immobilization techniques being utilized and their benefits and drawbacks. These methods typically fall into two categories: (1) direct immobilization and (2) use of crosslinkers. Direct immobilization techniques are usually simple and utilize the strong electrophilic functional groups on the nanofiber. While crosslinkers are used as an intermediary between the nanofiber substrate and the biomolecule, with some crosslinkers being present in the final product and others simply facilitating the reactions. We aim to provide an explanation of each immobilization technique, biomolecules commonly paired with said technique and the benefit of immobilization over the free biomolecule.

Tri-functional platform for the facile construction of dual-functional surfaces via a one-pot strategy

The scope of simultaneously introducing two new functionalities into the same polymeric substrate is largely limited to facile grafting approaches. Here, we designed a novel tri-functional platform and facilely constructed dual-functional surfaces in one pot by combining the "sulfur(vi)-fluoride exchange" (SuFEx) click reaction, photoinitiated polymerization and benzophenone photochemistry.

Reactive films fabricated using click sulfur(vi)–fluoride exchange reactions via layer-by-layer assembly

We describe a novel and efficient method to generate tunable multifunctional polymer films with a wide range of potential biomedical applications using the “sulfur(vi)–fluoride exchange” (SuFEx) click reaction.

AIE-active polysulfates via a sulfur(vi) fluoride exchange (SuFEx) click reaction and investigation of their two-photon fluorescence and cyanide detection in water and in living cells

Three polysulfates P1, P2 and P3 containing two representative AIE-active groups, tetraphenyl ethylene and naphthylamide, were successfully synthesized based on a sulfur(vi) fluoride exchange (SuFEx) click reaction.

Bioinspired hierarchically hairy particles for robust superhydrophobic coatings via a droplet dynamic template method

Bioinspired hierarchically hairy particles are prepared by using initiator droplets as dynamic templates to achieve a robust superhydrophobic coating.

A rapid one-step surface functionalization of polyvinyl chloride by combining click sulfur(vi)-fluoride exchange with benzophenone photochemistry

We demonstrated a rapid one-step strategy for polyvinyl chloride surface functionalization by combining click “sulfur(vi)-fluoride exchange” (SuFEx) reaction with benzophenone photochemistry.

Facile fabrication of a “Catch and Release” cellulose acetate nanofiber interface: a platform for reversible glycoprotein capture and bacterial attachment

We disclose boronic acid ligand-functionalized electrospun cellulose acetate nanofiber mats that can be used as a platform for reversible glycoprotein capture and bacterial attachment.