Nanoparticle-Induced Ellipse-to-Vesicle Morphology Transition of Rod–Coil–Rod Triblock Copolymer Aggregates

Abstract

Cooperative self-assembly behavior of rod-coil-rod poly(γ-benzyl-l-glutamate)-block-poly(ethylene glycol)-block-poly(γ-benzyl-l-glutamate) (PBLG-b-PEG-b-PBLG) amphiphilic triblock copolymers and hydrophobic gold nanoparticles (AuNPs) was investigated by both experiments and dissipative particle dynamics (DPD) simulations. It was discovered that pure PBLG-b-PEG-b-PBLG copolymers self-assemble into ellipse-like aggregates, and the morphology transforms into vesicles as AuNPs are introduced. When the hydrophobicity of AuNPs is close to that of the copolymers, AuNPs are homogeneously distributed in the vesicle wall. While for the AuNPs with higher hydrophobicity, they are embedded in the vesicle wall as clusters. In addition to the experimental observations, DPD simulations were performed on the self-assembly behavior of triblock copolymer/nanoparticle mixtures. Simulations well reproduced the morphology transition observed in the experiments and provided additional information such as chain packing mode in aggregates. It is deduced that the main reason for the ellipse-to-vesicle transition of the aggregates is attributed to the breakage of ordered and dense packing of PBLG rods in the aggregate core by encapsulating AuNPs. This study deepens our understanding of the self-assembly behavior of rod-coil copolymer/nanoparticle mixtures and provides strategy for designing hybrid polypeptide nanostructures.

Self‐Assembly of Rod‐Coil Block Copolymers on Carbon Nanotubes: A Route toward Diverse Surface Nanostructures

“…With increasing the DP of PBLG blocks (PBLG 119 ‐ b ‐PEG 112 , BCP1), the attraction between PBLG blocks is enhanced, which induces PBLG blocks pack orderly into helix nanostructures (Figure f). When the DP of the PBLG blocks is relatively large (PBLG 210 ‐ b ‐PEG 112 , BCP3), the attraction between PBLG blocks is strong, which restricts the morphology evolution in self‐assembly process, resultantly, discrete spheres on the surface of CNTs are formed (Figure c). Shown in Figure d is morphology of BCP1/CNT dispersion prepared using CNTs with a large diameter (OD = 140–160 nm).…”

Recent advances in the solution self‐assembly of amphiphilic “rod‐coil” copolymers

“…The resultant bioactive superstructures are of great interest for biological applications, including drug delivery, biomimetic materials, and tissue engineering, etc . This section concentrates on stimuli‐responsive self‐assembly systems of polypeptide‐containing rod‐coil BCPs …”

“…Zhu et al group did impressive studies on the self‐assembly of polypeptide‐based rod‐coil BCPs . With the assistance of computer simulation, they systematically investigated the self‐assembly behavior of PBLG‐ b ‐PEG/PBLG binary systems in solution .…”

“…This study demonstrated the possibility to create novel morphologies in a designed fashion through stimuli‐responsive self‐assembly under the assistance of computer simulation. In another interesting work, they studied the cooperative self‐assembly behavior of PBLG‐ b ‐PEG‐ b ‐PBLG triblock copolymers and gold nanoparticles (AuNPs) in THF/H 2 O mixed solvents by both experiments and dissipative particle dynamics (DPD) simulations . The pure triblocks with relatively longer PBLG blocks self‐organized into ellipse‐like structures, and the DPD simulation revealed that PBLG rods tended to take parallel and dense packing fashion in the core of the ellipse‐like aggregates.…”

Synthesis of an amphiphilic graft copolymer bearing a hydrophilic poly(acrylate acid) backbone for drug delivery of methotrexate

“…13,14 It is well known that the architecture of copolymers has great impact on their properties. 15 Amphiphilic block copolymers with linear architecture are known to form different morphologies in specic solvents, which brings lots of potential applications including drug delivery, [16][17][18][19] bioreactor, 20,21 and catalysis. 22,23 However, it has been showed that non-linear copolymers display fundamentally different properties compared to the linear copolymers.…”