Low-Temperature Synthesis of Thermoresponsive Diblock Copolymer Nano-Objects via Aqueous Photoinitiated Polymerization-Induced Self-Assembly (Photo-PISA) using Thermoresponsive Macro-RAFT Agents

Efficient Way to Generate Protein-Based Nanoparticles by in-Situ Photoinitiated Polymerization-Induced Self-Assembly

Protein-based nanoparticles with tailored properties by using different functional proteins as building blocks have many actual and potential applications in biomedicine, biotechnology, and nanotechnology. In this study, we demonstrated a facile and efficient way to synthesize protein-based nanoparticles by taking advantage of photoinitiated reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly by using multi-RAFT modified bovine serum albumin (BSA) as a macro-RAFT agent. The growth of the PHPMA chains results in the increase of the hydrophobicity of the star BSA-PHPMA conjugates, and when reaching the critical aggregation concentration in aqueous solution, they will aggregate into nanoparticles via the hydrophobic interaction of PHPMA. The generated nanoparticles also showed excellent encapsulation ability toward both hydrophobic and hydrophilic components, and as a proof of concept, after loading cancer drug DOX or biomacromolecule DNA, the protease-mediated release of the encapsulants was demonstrated. It is anticipated that the described method may open up new opportunities for designing a variety of protein-polymer self-assembled nanostructures tailored to specific applications.

Photoinitiated Polymerization-Induced Self-Assembly (Photo-PISA): New Insights and Opportunities

The polymerization-induced self-assembly (PISA) process is a useful synthetic tool for the efficient synthesis of polymeric nanoparticles of different morphologies. Recently, studies on visible light initiated PISA processes have offered a number of key research opportunities that are not readily accessible using traditional thermally initiated systems. For example, visible light mediated PISA (Photo-PISA) enables a high degree of control over the dispersion polymerization process by manipulation of the wavelength and intensity of incident light. In some cases, the final nanoparticle morphology of a single formulation can be modulated by simple manipulation of these externally controlled parameters. In addition, temporal (and in principle spatial) control over the Photo-PISA process can be achieved in most cases. Exploitation of the mild room temperature polymerizations conditions can enable the encapsulation of thermally sensitive therapeutics to occur without compromising the polymerization rate and their activities. Finally, the Photo-PISA process can enable further mechanistic insights into the morphological evolution of nanoparticle formation such as the effects of temperature on the self-assembly process. The purpose of this mini-review is therefore to examine some of these recent advances that have been made in Photo-PISA processes, particularly in light of the specific advantages that may exist in comparison with conventional thermally initiated systems.

Polymerization-Induced Self-Assembly of Homopolymer and Diblock Copolymer: A Facile Approach for Preparing Polymer Nano-Objects with Higher-Order Morphologies

Polymerization-induced self-assembly of homopolymer and diblock copolymer using a binary mixture of small chain transfer agent (CTA) and macromolecular chain transfer agent (macro-CTA) is reported. With this system, homopolymer and diblock copolymer were formed and chain extended at the same time to form polymer nano-objects. The molar ratio of homopolymer and diblock copolymer had a significant effect on the morphology of the polymer nano-objects. Porous vesicles, porous nanospheres, and micron-sized particles with highly porous inner structure were prepared by this method. We expect that this method will greatly expand the promise of polymerization-induced self-assembly for the synthesis of a range of polymer nano-objects with unique morphologies.

Thermoresponsive gels directly obtained via visible light-mediated polymerization-induced self-assembly with oxygen tolerance

A thermoresponsive reversible hydrogel is developed by PET-RAFT mediated PISA in aqueous solution at room temperature without deoxygenation.

Rapid synthesis of well-defined all-acrylic diblock copolymer nano-objects via alcoholic photoinitiated polymerization-induced self-assembly (photo-PISA)

A series of well-defined all-acrylic poly(hydroxyethyl acrylate)-poly(isobornyl acrylate) (PHEA-PIBOA) diblock copolymer nano-objects were prepared by photoinitiated polymerization-induced self-assembly (photo-PISA).

Adding a solvophilic comonomer to the polymerization-induced self-assembly of block copolymer and homopolymer: a cooperative strategy for preparing large compound vesicles

We report a RAFT dispersion polymerization of styrene and 4-vinylpyridine in methanol/water at 70 °C. The polymerization was mediated by a binary mixture of DDMAT and mPEG₄₅-DDMAT.

Facile preparation of hybrid vesicles loaded with silica nanoparticles via aqueous photoinitiated polymerization-induced self-assembly

We report a photoinitiated dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) in the presence of silica nanoparticles using a poly(ethylene glycol) methyl ether (mPEG) macromolecular chain transfer agent (macro-CTA).

Application of oxygen tolerant PET-RAFT to polymerization-induced self-assembly

The inhibitory effects of molecular oxygen in PET-RAFT polymerization can be overcome by the addition of singlet oxygen quenchers. This oxygen tolerant approach is compatible with a range of organic solvents and can be used to synthesize nanoparticles according to a PISA process.

An insight into aqueous photoinitiated polymerization-induced self-assembly (photo-PISA) for the preparation of diblock copolymer nano-objects

Photoinitiated polymerization-induced self-assembly (photo-PISA) is utilized to investigate the sole effect of reaction temperature on PISA.