Addition-fragmentation Chain Transfer Polymerization Research Articles

Polyoxometalate-Polymer Directed Macromolecular Architectonics of Silver Nanoparticles as Effective Antimicrobials.

A novel inorganic-organic-inorganic ternary bioactive material formulated on antimicrobial peptide-based polymer has been reported. Supramolecular approach has been employed to incorporate molecularly crowded tyrosine-based polymer stabilized silver nanoparticles into membrane bound vesicles exploiting polyoxometalate-triggered surface templating strategy. Utilizing the covalent reversible addition fragmentation chain transfer (RAFT) polymerization and exploiting templated supramolecular architectonics at biopolymer interface, the bioactive ternary polymeric nanohybrids have been designed against Shigellosis leveraging the antibacterial activities of silver nanoparticle, cationic amphiphilic tyrosine polymer and inorganic polyoxometalate. The detail investigation against Shigella flexneri 2a cell line demonstrates that the collaborative mechanism of the ternary hybrid composite enhances the bactericidal activity in comparison to only polyoxometalate and polymer stabilized silver nanoparticle with an altered mechanism of action which is established via detailed biological analysis.

Tyrosine-Phosphorylated Peptide Imprinted Particles Prepared by Reversible Addition–Fragmentation Chain Transfer Polymerization and “Epitope” Strategy: Selective Recognition of Phosphorylated Angiotensin II

Tyrosine-Phosphorylated Peptide Imprinted Particles Prepared by Reversible Addition–Fragmentation Chain Transfer Polymerization and “Epitope” Strategy: Selective Recognition of Phosphorylated Angiotensin II

Pyrazino[2,3-f][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Pyrazino[2,3-<i>f</i>][1,10]phenanthroline Derivatives as Robust Photocatalysts Enabling ppm-Level Organocatalyzed Photoinduced Electron/Energy Transfer Reversible Addition–Fragmentation Chain Transfer Polymerization

Four-Component Statistical Copolymers by RAFT Polymerization.

This manuscript serves as the starting point for in-depth research of multicomponent, statistical, methacrylate-based copolymers that potentially mimic the behavior of proteins in aqueous solutions. These synthetic macromolecules are composed of specially chosen comonomers: methacrylic acid (MAA), oligoethylene glycol methyl ether methacrylate (OEGMA475), 2-(dimethylamino)ethyl methacrylate (DMAEMA) and benzyl methacrylate (BzMA). Monomer choice was based on factors such as the chemical nature of pendant functional groups, the polyelectrolyte/polyampholyte and amphiphilic character and the overall hydrophobic-hydrophilic balance (HLB) of the obtained quaterpolymers. Their synthesis was achieved via a one-pot reversible addition fragmentation chain transfer (RAFT) polymerization in two distinct compositions and molecular architectures, linear and hyperbranched, respectively, in order to explore the effects of macromolecular topology. The resulting statistical quaterpolymers were characterized via 1H-NMR and ATR-FTIR spectroscopies. Their behavior in aqueous solutions was studied by dynamic (DLS) and electrophoretic light scattering (ELS) and fluorescence spectroscopy (FS), producing vital information concerning their self-assembly and the structure of the formed aggregates. The physicochemical studies were extended by tuning parameters such as the solution pH and ionic strength. Finally, the quaterpolymer behavior in FBS/PBS solutions was investigated to test their colloid stability and biocompatibility in an in vivo-mimicking, biological fluid environment.

Unravelling Competitive Interactions between Polymer Side Chains and End Groups with β-Cyclodextrin.

This study investigates unexpected competitive host-guest interactions of β-cyclodextrin (β-CD), which can occur with polymers in aqueous solution, using the examples of the two polymers poly(oligo(ethylene glycol) methyl ether methacrylate) and poly(glycerol mono methacrylate). Systematic structural modifications of the polymer provide insight into the host-guest interaction with β-CD and the competition between side chains and end groups such as hydrophobic end groups remaining from reversible addition fragmentation chain transfer polymerization or intentionally implemented molecular recognition units such as arylazopyrazole photoswitches.

Fluorine-modified polymers reduce the adsorption of immune-reactive proteins to PEGylated gold nanoparticles.

Aim: To investigate the influence of fluorine in reducing the adsorption of immune-reactive proteins onto PEGylated gold nanoparticles. Methods: Reversible addition fragmentation chain transfer polymerization, the Turkevich method and ligand exchange were used to prepare polymer-coated gold nanoparticles. Subsequent in vitro physicochemical and biological characterizations and proteomic analysis were performed. Results: Fluorine-modified polymers reduced the adsorption of complement and other immune-reactive proteins while potentially improving circulatory times and modulating liver toxicity by reducing apolipoprotein E adsorption. Fluorine actively discouraged phagocytosis while encouraging the adsorption of therapeutic targets, CD209 and signaling molecule calreticulin. Conclusion: This study suggests that the addition of fluorine in the surface coating of nanoparticles could lead to improved performance in nanomedicine designed for the intravenous delivery of cargos.

Synthesis via Reversible Addition–Fragmentation Chain Transfer Polymerization and Deep Control Property of Amphiphilic Self-assembled Poly(ethylene oxide)-block-polystyrene

Synthesis via Reversible Addition–Fragmentation Chain Transfer Polymerization and Deep Control Property of Amphiphilic Self-assembled Poly(ethylene oxide)-<i>block</i>-polystyrene

Diblock Copolymers of Methacryloyloxyethyl Phosphorylcholine and Dopamine Methacrylamide: Synthesis and Real-Time Adsorption Dynamics by SEIRAS and RAIRS.

Amphiphilic diblock copolymers containing a block of 2-methacryloyloxyethyl phosphorylcholine (MPC) with unique properties to prevent nonspecific protein adsorption and enhance lubrication in aqueous media and a block of dopamine methacrylamide (DOPMA) distinguished by excellent adhesion performance were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization for the first time. The DOPMA monomer with an acetonide-protected catechol group (acetonide-protected dopamine methacrylamide (ADOPMA)) was used, allowing the prevention of undesirable side reactions during polymerization and oxidation during storage. The adsorption behavior of the diblock copolymers with protected and unprotected catechol groups on gold surfaces was probed using attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy, surface-enhanced infrared absorption spectroscopy (SEIRAS), and reflection-absorption infrared spectroscopy (RAIRS). The copolymers pMPC-b-pADOPMA demonstrated physisorption with rapid adsorption and ultrasound-assisted desorption, while the copolymers pMPC-b-DOPMA exhibited chemical adsorption with slower dynamics but a stronger interaction with the gold surface. SEIRAS and RAIRS allowed proving the reorientation of the diblock copolymers during adsorption, demonstrating the exposure of the pMPC block toward the aqueous phase.

Oxygen-Tolerant Fabrication of Large-Area Hydrogel Films via Photoinduced Electron/Energy Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

Oxygen-Tolerant Fabrication of Large-Area Hydrogel Films via Photoinduced Electron/Energy Transfer-Reversible Addition–Fragmentation Chain Transfer Polymerization

Tunable Cell-Adhesive Surfaces by Surface-Initiated Photoinduced Electron-Transfer-Reversible Addition-Fragmentation Chain-Transfer Polymerization.

Cell adhesion involves many interactions between various molecules on the cell membrane (receptors, coreceptors, integrins, etc.) and surfaces or other cells. Cell adhesion plays a crucial role in the analysis of immune response, cancer treatment, tissue engineering, etc. Cell-cell adhesion can be quantified by measuring cell avidity, which defines the total interaction strength of the live cell binding. Typically, those investigations use tailor-made, reusable chips or surfaces onto which cells are cultured to form a monolayer to which other cells can bind. Cell avidity can then be measured by applying a force and quantifying cell-cell bond ruptures. The subsequent cleaning and reactivation of such biochip and biointeractive surfaces often require repeated etching, leading to device damage. Furthermore, it is often of great interest to harvest the cells that remain bound at the end of an avidity experiment for further analysis or use. It is, therefore, advantageous to pursue coating methods that allow tunable cell adhesion. This work presents temperature-switchable poly(di(ethylene glycol) methyl ether methacrylate) brush-based cell-interactive coatings produced by surface-initiated photoinduced electron-transfer reversible addition-fragmentation chain-transfer polymerization. The temperature switch of these brushes was explored by using a quartz crystal microbalance with dissipation monitoring, chemical composition, and physicochemical properties by atom force microscopy, X-ray photoelectron spectroscopy, single-molecule force spectroscopy, and ellipsometry.

Photoiniferter-RAFT polymerization mediated by bis(trithiocarbonate) disulfides

Photoiniferter reversible addition fragmentation chain transfer (PI-RAFT) polymerization has gained significant attention; however, scalable methodologies are still lacking.

Dual-templating synthesis of superhydrophobic Fe3O4/PSt porous composites for highly efficient oil-water separation

Fe3O4/PSt porous composites with low density, interconnected network structure and superhydrophobic were prepared successfully by a dual-templating method, including High Internal Phase Emulsion (HIPEs) template method and the introduction of organic template species. It was worth mentioning that a novel amphiphilic di-block copolymers P(DMAEMA-b-St) were prepared as emulsifier by reversible addition fragmentation chain transfer (RAFT) polymerization method. At the same time, the effects of PS block length, emulsifier content, Fe3O4 content, DVB content and dispersed phase proportion on HIPEs droplet size and the corresponding polyHIPEs oil absorption were researched. The results showed that the oil adsorption capacity of 9.43 g/g toward toluene under optimal conditions. Subsequently, adsorption isotherm and adsorption kinetics were investigated. The results were shown that the adsorption of oil on adsorbent followed Freundlich model and pseudo-second-order (PSO) model. In addition, the adsorption experiments on a variety of oils demonstrated the wide applicability of Fe3O4/PSt porous composites. The cycling experiments proved that the Fe3O4/PSt porous composites had excellent cycling ability, were easy to recover and could be reused for multiple times. Finally, the adsorption column experiments showed that Fe3O4/PSt porous composites had powerful potential for industrial applications.

Elucidating the Role of Optical Activity of Polymers in Protein-Polymer Interactions.

Proteins are biomolecules with potential applications in agriculture, food sciences, pharmaceutics, biotechnology, and drug delivery. Interactions of hydrophilic and biocompatible polymers with proteins may impart proteolytic stability, improving the therapeutic effects of biomolecules and also acting as excipients for the prolonged storage of proteins under harsh conditions. The interactions of hydrophilic and stealth polymers such as poly(ethylene glycol), poly(trehalose), and zwitterionic polymers with various proteins are well studied. This study evaluates the molecular interactions of hydrophilic and optically active poly(vitamin B5 analogous methacrylamide) (poly(B5AMA)) with model proteins by fluorescence spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and circular dichroism (CD) spectroscopy analysis. The optically active hydrophilic polymers prepared using chiral monomers of R-(+)- and S-(-)-B5AMA by the photo-iniferter reversible addition fragmentation chain transfer (RAFT) polymerization showed concentration-dependent weak interactions of the polymers with bovine serum albumin and lysozyme proteins. Poly(B5AMA) also exhibited a concentration-dependent protein stabilizing effect at elevated temperatures, and no effect of the stereoisomers of polymers on protein thermal stability was observed. NMR analysis, however, showed poly(B5AMA) stereoisomer-dependent changes in the secondary structure of proteins.

Preparation of two zwitterionic polymer functionalized stationary phases and comparative evaluation under mixed-mode of reversed phase/ hydrophilic interaction/ion exchange chromatography

Zwitterions are a promising choice to prepare separation materials because of their hydrophilicity and biocompatibility. We described the preparation of two zwitterionic polymer functionalized stationary phases and evaluation under mixed-mode chromatography. A zwitterionic monomer, S-(4-vinylbenzyl) cysteine (SVC), was synthesized and bonded to silica via reversible addition fragmentation chain transfer (RAFT) polymerization to afford a zwitterionic stationary phase, Sil-SVC. A hydrophobic monomer, N-(4-phenylbutan-2-yl) acrylamide (NPA), was copolymerized with SVC onto the stationary phase (Sil-SVCNPA) for comparison. The stationary phases were characterized with FT-IR, TGA, EA, and zeta-potential measurements. Mobile phase composition (ACN content, pH and salt concentration) was varied to study the retention property. Linear solvation energy relationship and Van't Hoff plot were used to investigate the retention mechanism and how chromatographic conditions influenced it. Both stationary phases showed a mixed-mode of RPLC/HILIC/IEC and satisfactory performance in separating hydrophobic analytes (alkylbenzenes and polycyclic aromatic hydrocarbons), hydrophilic nucleotide and bases, and anions, high column efficiency of 60,000 plates·m−1 was achieved. In summary, zwitterionic polymers are attractive options to prepare stationary phases and the retention property can be easily regulated by copolymer.

Realizing Cross-linking-free Acrylic Pressure-Sensitive Adhesives with Intensive Chain Entanglement through Visible-Light-Mediated Photoiniferter-Reversible Addition-Fragmentation Chain-Transfer Polymerization.

A versatile and simplified synthesis scheme for intensively entangled acrylic pressure-sensitive adhesives (PSAs) was developed in this study by leveraging visible-light-driven controlled radical polymerization (photoiniferter/reversible addition-fragmentation chain-transfer polymerization) of acrylic copolymers under a controlled manner; the approach was differentiated by a single factor; molecular weight (Mw up to 2.8 MDa) with identical compositions. By manipulating Mw up to ultra-high ranges, PSAs with diversified viscoelastic properties were prepared and then assessed with a focus on realizing PSAs with a maximized degree of entanglement per chain through domination of high Mw contents, to help achieve excellent cohesiveness without a reinforcing cross-linking network. Moreover, fully linear solvent-soluble poly(acrylate)s were synthesized to facilitate reprocessing and reuse, highlighting the sustainability of the devised method and, consequently, its potential to be applied for effectively reducing industrial or daily waste.

Synthetic copolymers with natural product side‐chain pendents

AbstractDehydroabietic acid is a natural product in the class of rosins. Here we report the design, synthesis and characterization of copolymers containing dehydroabietate side‐chain pendents, derived from homologated dehydroabietic ethyl methacrylate and tert‐butoxy carbonyl (Boc) l‐alanine methacryloyloxyethyl ester with varying comonomer proportions by reversible addition fragmentation chain transfer polymerization. The cleavage of Boc groups from the copolymers resulted in water‐soluble copolymers with cationic surface charge. Since proper hydrophobic−hydrophilic balance in a single polymer chain is maintained, the copolymers self‐assembled in aqueous media with a critical aggregation concentration of 2.8–3.0 mg L−1, confirmed by fluorescence spectroscopy. 1H NMR spectroscopy, dynamic light scattering, SEM and AFM were used to further investigate the aqueous solution self‐assembly of random copolymers. The collective findings from 1H NMR, dynamic light scattering, SEM and AFM clearly revealed the existence of micellar particles in water with alanine units on the surface of the nanoaggregates and homologated dehydroabietate pendents along with the hydrophobic main‐chain backbone in the core. In addition, to get a clear insight into the nanoaggregates' potential for drug encapsulation in aqueous medium, Nile Red was incorporated as a model hydrophobic dye. © 2023 Society of Industrial Chemistry.

Size-Controlled Ammonium-Based Homopolymers as Broad-Spectrum Antibacterials.

Ammonium group containing polymers possess inherent antimicrobial properties, effectively eliminating or preventing infections caused by harmful microorganisms. Here, homopolymers based on monomers containing ammonium groups were synthesized via Reversible Addition Fragmentation Chain Transfer Polymerization (RAFT) and evaluated as potential antibacterial agents. The antimicrobial activity was evaluated against Gram-positive (M. luteus and B. subtilis) and Gram-negative bacteria (E. coli and S. typhimurium). Three polymers, poly(diallyl dimethyl ammonium chloride), poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and poly(vinyl benzyl trimethylammonium chloride), were examined to explore the effect of molecular weight (10 kDa, 20 kDa, and 40 kDa) on their antimicrobial activity and toxicity to mammalian cells. The mechanisms of action of the polymers were investigated with dye-based assays, while Scanning Electron Microscopy (SEM) showed collapsed and fused bacterial morphologies due to the interactions between the polymers and components of the bacterial cell envelope, with some polymers proving to be bactericidal and others bacteriostatic, while being non-hemolytic. Among all the homopolymers, the most active, non-Gram-specific polymer was poly([2-(methacryloyloxy)ethyl]trimethylammonium chloride), with a molecular weight of 40 kDa, with minimum inhibitory concentrations between 16 and 64 µg/mL, showing a bactericidal mode of action mediated by disruption of the cytoplasmic membrane. This homopolymer could be useful in biomedical applications such as surface dressings and in areas such as eye infections.

A novel star polymer for regulating fluid loss in oil-based mud under high temperature conditions

Oil-Based Mud (OBM) is a highly effective drilling fluid system for challenging wellbore conditions such as water-sensitive and high-temperature drilling operations. To minimize filtration loss and achieve thin filter cake, fluid loss control additives are essential. This study introduces a star polymer as an alternative to traditional additives like gilsonite or linear polymer. The star polymer was synthesized using Reversible Addition Fragmentation Chain Transfer polymerization (RAFT) with hydrophilic and lipophilic monomers and crosslinkers. Mud properties such as rheology, fluid loss, mud cake thickness, and emulsion stability were evaluated for OBM and compared with commercially available fluid loss control additives at simulated downhole pressure and temperatures. Spectroscopy and thermogravimetric analysis were used to determine the chemical architecture and thermal stability of the star polymer. The results showed that the star polymer demonstrated thermal stability up to 225 °C, resulting in a small amount of fluid loss volume and ultra-thin filter cake for OBM systems with mud weight at 10.5 ppg and 13.4 ppg. Furthermore, the star polymer improved emulsion stability without significantly affecting plastic viscosity (PV), unlike commercially available fluid loss control additives. The results were consistent for both diesel and synthetic oil-based mud systems.

Sulfonium-cation-containing aggregation-induced emission block copolymers: self-assembly, multicolor emission, and detection for DNA polyplexes

Amphiphilic aggregation-induced emission (AIE) polymers have emerged as highly attractive materials that exhibit the synergistic effect of functional polymeric self-assemblies with AIE luminogens. In this study, we design and synthesize block copolymers containing sulfonium cations and a hydrophobic tetraphenylethene (TPE) unit. These copolymers exhibit distinct self-assembly behaviors with AIE, polyplex formation with DNA, and tunable color emissions. Amphiphilic block copolymer PMTEAMe+Cl--b-PATPE, consisting of 4-(1,2,2-triphenylvinyl)phenyl acrylate (ATPE) and cationized 2-(methylthio)ethyl acrylate (MTEAMe+Cl-), was synthesized via reversible addition–fragmentation chain transfer polymerization, followed by cationization. Self-assembled structures containing TPE-aggregated cores and cationic PMTEAMe+Cl- shells and their emission behaviors were investigated. By introducing charged fluorescent dyes (Rose Bengal and Rhodamine B) into aqueous solutions of amphiphilic PMTEAMe+Cl--b-PATPE, we observed a shift in the emission color from blue to orange/red, which was attributed to the electrostatic interactions and fluorescence resonance energy transfer between the dyes and the copolymers. The emission color and intensity were also governed by polyplex formation between the negatively charged DNA and the positively charged sulfonium segments in the shell, depending on the charged states of the dyes. This system provides a method for efficient visual detection of DNA polyplex formation using multicolor fluorescent coding.

Amorphous solid dispersions of lidocaine and lidocaine HCl produced by ball milling with well-defined RAFT-synthesised methacrylic acid polymers

This study focuses on the use of methacrylic acid polymers synthesised via the Reversible Addition Fragmentation chain Transfer (RAFT) polymerisation method for the production of amorphous solid dispersions (ASDs) by ball milling, to kinetically solubilize a poorly water-soluble model drug. The solid-state characteristics and the physical stability of the formulations were investigated using X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. This was followed by dissolution studies in different media. It was discovered that the acidic polymers of methacrylic acid were capable of interacting with the weakly basic drug lidocaine and its hydrochloride salt form to produce ASDs when a polymer to drug ratio of 70:30 w/w was used. The ASDs remained amorphous following storage under accelerated aging conditions (40 °C and 75% relative humidity) over 8 months. Fast dissolution and increased lidocaine solubility in different media were obtained from the ASDs owing to the reduced microenvironment pH and enhanced solubilization of the drug caused by the presence of the acidic polymer in the formulation. Production of ASDs using well-defined RAFT-synthesised acidic polymers is a promising formulation strategy to enhance the pharmaceutical properties of basic poorly water-soluble drugs.