Preparation of giant vesicles containing quaternary ammonium salt of 2-(dimethylamino)ethyl methacrylate through photo nitroxide-mediated controlled/living radical polymerization-induced self-assembly

Modern Trends in Polymerization-Induced Self-Assembly

Polymerization-induced self-assembly (PISA) is a powerful and versatile technique for producing colloidal dispersions of block copolymer particles with desired morphologies. Currently, PISA can be carried out in various media, over a wide range of temperatures, and using different mechanisms. This method enables the production of biodegradable objects and particles with various functionalities and stimuli sensitivity. Consequently, PISA offers a broad spectrum of potential commercial applications. The aim of this review is to provide an overview of the current state of rational synthesis of block copolymer particles with diverse morphologies using various PISA techniques and mechanisms. The discussion begins with an examination of the main thermodynamic, kinetic, and structural aspects of block copolymer micellization, followed by an exploration of the key principles of PISA in the formation of gradient and block copolymers. The review also delves into the main mechanisms of PISA implementation and the principles governing particle morphology. Finally, the potential future developments in PISA are considered.

Polymerization-Induced Self-Assembly for Efficient Fabrication of Biomedical Nanoplatforms

Amphiphilic copolymers can self-assemble into nano-objects in aqueous solution. However, the self-assembly process is usually performed in a diluted solution (<1 wt%), which greatly limits scale-up production and further biomedical applications. With recent development of controlled polymerization techniques, polymerization-induced self-assembly (PISA) has emerged as an efficient approach for facile fabrication of nano-sized structures with a high concentration as high as 50 wt%. In this review, after the introduction, various polymerization method-mediated PISAs that include nitroxide-mediated polymerization-mediated PISA (NMP-PISA), reversible addition-fragmentation chain transfer polymerization-mediated PISA (RAFT-PISA), atom transfer radical polymerization-mediated PISA (ATRP-PISA), and ring-opening polymerization-mediated PISA (ROP-PISA) are discussed carefully. Afterward, recent biomedical applications of PISA are illustrated from the following aspects, i.e., bioimaging, disease treatment, biocatalysis, and antimicrobial. In the end, current achievements and future perspectives of PISA are given. It is envisioned that PISA strategy can bring great chance for future design and construction of functional nano-vehicles.

Preparation of core–shell nanoparticles via emulsion polymerization induced self-assembly using a maleamic acid-α-methyl styrene copolymer as a macro-initisurf

An amphiphilic maleamic acid-α-methyl styrene copolymer (macro-initisurf) acting as a macroinitiator and emulsifier for the emulsion polymerization induced self-assembly of acrylate monomers to prepare core–shell nanoparticles.

Hybrid giant lipid vesicles incorporating a PMMA-based copolymer

BACKGROUND

In recent years, there has been a growing interest in the formation of copolymer-lipid hybrid self-assemblies, which allow combining and improving the main features of pure lipid-based and copolymer-based systems known for their potential applications in the biomedical field. As the most common method used to obtain giant vesicles is electroformation, most systems so far used low T_g polymers for their flexibility at room temperature.

METHODS

Copolymers used in the hybrid vesicles have been synthesized by a modified version of the ATRP, namely the Activators ReGenerated by Electron Transfer ATRP and characterized by NMR and DSC. Giant hybrid vesicles have been obtained using electroformation and droplet transfer method. Confocal fluorescence microscopy was used to image the vesicles.

RESULTS

Electroformation enabled to obtain hybrid vesicles in a narrow range of compositions (15 mol% was the maximum copolymer content). This range could be extended by the use of a droplet transfer method, which enabled obtaining hybrid vesicles incorporating a methacrylate-based polymer in a wide range of compositions. Proof of the hybrid composition was obtained by fluorescence microscopy using labeled lipids and copolymers.

CONCLUSIONS

This work describes for the first time, to the best of our knowledge, the formation of giant hybrid polymer/lipid vesicles formed with such a content of a polymethylmethacrylate copolymer, the glass temperature of which is above room temperature.

GENERAL SIGNIFICANCE

This work shows that polymer structures, more complex than the ones mostly employed, can be possibly included in giant hybrid vesicles by using the droplet transfer method. This will give easier access to functionalized and stimuli-responsive giant vesicles and to systems exhibiting a tunable permeability, these systems being relevant for biological and technological applications.

Perforated vesicles composed of amphiphilic diblock copolymer: new artificial biomembrane model of nuclear envelope

With the aim of creating a new artificial model of a biomembrane for the nuclear envelope, perforated vesicles were prepared employing an amphiphilic diblock copolymer of poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid-random-2,2,6,6-tetramethyl-4-piperidyl methacrylate), PMAA-b-P(MMA-r-MAA-r-TPMA), by polymerization-induced self-assembly through photo nitroxide-mediated controlled/living radical polymerization (photo NMP). The photo NMP in an aqueous methanol solution produced spherical vesicles perforated with various holes and pores in the surface. The perforation of the vesicles was prevented by trifluoroacetic acid based on the disturbance of the MAA-TPMA interaction in the hydrophobic block chain. The investigation of the morphology changes by the polymerization progress revealed that the perforated spherical vesicles were produced within the membrane of contorted huge vesicles that were formed during the early stage of the polymerization due to the extension of the hydrophobic block chain. The perforated vesicles were found to show a reversible thermo-responsive behavior in the range of 25-50 °C based on dynamic light scattering and transmittance measurements. The vesicles were fused and divided into much smaller vesicles at high temperature, but were restored by cooling. However, the restored vesicles only had a few holes and no pores in the surface. The rearrangement of the MAA-TPMA interaction at high temperature produced more morphologically stable non-perforated vesicles.