Synthesis of Well-Defined Poly(vinyl alcohol-co-vinyl acetate) Copolymers by Alcoholysis of Poly(vinyl acetate) Synthesized by Macromolecular Design via Interchange of Xanthate Polymerization, and Their Use as a Stabilizer in Emulsion (Co)polymerization of Vinyl Acetate

This work aims at synthesizing tailor-made poly(vinyl alcohol-co-vinyl acetate) (PVA) amphiphilic copolymers, obtained by alcoholysis of poly(vinyl acetate) (PVAc) that could display improved properties as stabilizers compared to commercially available PVAs. Well-defined PVAs with different alcoholysis degrees were produced from a library of PVAc homopolymers synthesized by macromolecular design via interchange of xanthate polymerization and exhibiting different degrees of polymerization degrees. Subsequently, these PVAs were evaluated as stabilizers in the emulsion copolymerization of VAc and vinyl neodecanoate (VERSA 10, referred to as V10) and compared to a commercially available reference PVA obtained by alcoholysis of PVAc formed by conventional radical polymerization. In all cases, stable latexes were obtained and compared in terms of their colloidal characteristics. To identify the best stabilizer candidate, the amount of PVA remaining in water and not participating to the particle stabilization was evaluated in each case.

Application of vinyl polymer-based materials as nucleic acids carriers in cancer therapy

Nucleic acid-based therapies have changed the paradigm of cancer treatment, where conventional treatment modalities still have several limitations in terms of efficacy and severe side effects. However, these biomolecules have a short half-life in vivo, requiring multiple administrations, resulting in severe suffering, discomfort, and poor patient compliance. In the early days of (nano)biotechnology, these problems caused concern in the medical community, but recently it has been recognized that these challenges can be overcome by developing innovative formulations. This review focuses on the use of vinyl polymer-based materials for the protection and delivery of nucleic acids in cancer. First, an overview of the properties of nucleic acids and their versatility as drugs is provided. Then, key information on the achievements to date, the most effective delivery methods, and the evaluation of functionalization approaches (stimulatory strategies) are critically discussed to highlight the importance of vinyl polymers in the new cancer treatment approaches. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures.

Development of targeted micelles and polymersomes prepared from degradable RAFT-based diblock copolymers and their potential role as nanocarriers for chemotherapeutics

Modern polymerisation techniques allow synthesis of functional block copolymers that can self-assemble into degradable nanoparticles (NPs) of different sizes and conformations.

Statistical and Block Copolymers of Ethylene and Vinyl Acetate via Reversible Addition-Fragmentation Chain Transfer Polymerization

A dithiocarbamate chain transfer agent (CTA) based on Z-group substituted with a diphenyl amine (-NPh₂ ) moiety is selected for the synthesis of statistical and diblock copolymers of ethylene and vinyl acetate via reversible addition-fragmentation chain transfer polymerization. Benefiting from the good chain growth control of polyethylene (PE), poly(vinyl acetate) (PVAc), and poly(ethylene-co-vinyl acetate) (EVA) achieved with this CTA, linear diblock copolymers of the type EVA-b-PE, EVA-b-EVA, and PVAc-b-EVA are successfully synthesized. A three-arm EVA star is additionally obtained starting from a trifunctional dithiocarbamate CTA.

Synthesis and properties of a stimulus-responsive block polymer

In this study, the synthesis of small molecules and use of an improved “one-pot” method to synthesize the reversible addition–fragmentation chain transfer polymerization (RAFT) reagents have been reported. By comparing with the RAFT reagents synthesized by the traditional “step-by-step” method, it was observed that the reagents synthesized by the two methods had the same structure, however, the improved “one-pot” preparation method results in a significantly higher yield. Subsequently, two different macromolecular CTA segments (PVP-CTA-PVP and PDMAEMA-CTA-PDMAEMA) were prepared by RAFT polymerization, followed by the synthesis of the block polymer PDMAEMA-b-PVP-CTA-PVP-b-PDMAEMA. Through FITR, NMR, GPC and DLS analysis of the block polymer, it was observed that the isotacticity gradually became dominant as the degree of polymerization increased. Further, using NMR spectroscopy to study the effect of pH on the block polymer, the ionization degree of the synthesized polymer in the tumor tissue environment was observed to range between 86.32% to 99.50%, which proved that the synthesized polymers exhibit significant prospects in the medical application.

In this study, two different macromolecular CTA segments (PVP-CTA-PVP and PDMAEMA-CTA-PDMAEMA) were prepared by RAFT polymerization, followed by the synthesis of the block polymer PDMAEMA-b-PVP-CTA-PVP-b-PDMAEMA.

A study on the preparation of alkyne functional nanoparticlesviaRAFT emulsion polymerisation

We evaluate the parameters surrounding the preparation of colloidally stable alkyne functional latex nanoparticlesviaRAFT emulsion polymerisation.

Synthesis of Amphiphilic Block Copolymers Containing Chiral Polythiophene Chains and Their Micelle Formation and Chiroptical Properties

Amphiphilic block copolymers consisting of hydrophobic regioregular head-to-tail (HT) chiral ((S)-poly-1a-b-poly-3) or achiral (poly-1b-b-poly-3) polythiophene chains and a hydrophilic poly(acrylic acid) chain were synthesized. (S)-Poly-1a-b-poly-3 with a chiral polythiophene block formed a micelle in water that exhibited a characteristic induced circular dichroism (ICD) in the π–π* transition region due to the formation of supramolecular π-stacked chiral aggregates of the chiral polythiophene blocks in the core. These aggregates were stable, showing no precipitation for more than 5 days. Micelles consisting of chiral (S)-poly-1a-b-poly-3 and achiral poly-1b-b-poly-3 showed negative nonlinear effects on supramolecular chiral aggregate formation in the core. Chiral polythiophene aggregates formed in (S)-poly-1a-b-poly-3 micelle cores were stabilized by the crosslinking of poly(acrylic acid) blocks with diamines in the shell. The ICD intensity of the (S)-poly-1a-b-poly-3 micelle after shell crosslinking showed almost no change with temperature, while that before shell crosslinking decreased with increasing temperature.

Thermo and pH dual-responsive drug-linked pseudo-polypeptide micelles with a comb-shaped polymer as a micellar exterior

The thermo and pH dual-responsive drug-linked pseudo-polypeptide micelles were prepared by a self-assembly strategy.

Synthesis of well-defined alkyne terminated poly(N-vinyl caprolactam) with stringent control over the LCST by RAFT

The reversible addition-fragmentation chain transfer (RAFT) of N-vinyl caprolactam (NVCL) using two new xanthates with alkyne functionalities is reported. The kinetic data obtained for polymerization of this non-activated monomer using a protected alkyne-terminated RAFT agent (PAT-X1) revealed a linear increase of the polymer molecular weight with the monomer conversion as well as low dispersity (Đ) during the entire course of the polymerization. The system reported here allowed us to enhance the final conversion, diminish Đ and reduce the polymerization temperature compared to the typical values reported in the scarce literature available for the RAFT polymerization of NVCL. The resulting PNVCL was fully characterized using 1H nuclear magnetic resonance (1H NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), Fourier-transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) techniques. The temperature-responsive features of PNVCL in aqueous solutions were fully investigated under different conditions using turbidimetry. The presented strategy allows the synthesis of well-defined PNVCL with sharp and reversible phase transition temperatures around 37 °C. By manipulating the polymer molecular weight, or the solution properties, it is possible to tune the PNVCL phase transition. As a proof-of concept, the alkyne functionalized PNVCL was used to afford new linear block copolymers, by reacting with an azide-terminated poly(ethylene glycol) (N3-PEG) through the copper catalyzed azide-alkyne [3+2] dipolar cycloaddition (CuAAC) reaction. The results presented establish a robust system to afford the synthesis of PNCVL with fine tuned characteristics that will enable more efficient exploration of the remarkable potential of this polymer in biomedical applications.