Synthesis and applications of polymer cubosomes and hexosomes

Abstract

The synthesis and use of polymer cubosomes have received significant attention in recent years. Polymer cubosomes are highly stable colloidal particles with triply periodic minimal surface. Inherently, polymer cubosomes have several advantages over other nanostructures like micelles and vesicles as they are quite uniform and porous structures. Due to the large specific surface area of the interior and bicontinuous nature, they have the capacity to load significant amounts of hydrophobic and hydrophilic substances. Additionally, their properties make them suitable for use as nanotemplates, catalyst supports, and nanovehicles for the separation and regulated release of biomolecules. Regarding their synthesis, block copolymers that may form cubosomes are still few in number, in part because different block copolymers require various self‐assembly conditions. In order to create polymer cubosomes, five different self‐assembly techniques have been reported, including the co‐solvent method, flash nanoprecipitation, evaporation‐induced self‐assembly, solvent‐diffusion‐evaporation‐mediated self‐assembly, and polymerization‐induced self‐assembly. This review article describes various synthetic techniques for creating polymer cubosomes and goes into further depth on recent uses for polymer cubosomes. It is anticipated that this article may offer some helpful guidance to researchers interested in the different applications of polymer cubosomes.

Photocleavable Polymer Cubosomes: Synthesis, Self-Assembly, and Photorelease

“…The formation of inverse BCP morphologies has typically been reported to follow a morphological evolution driven by changes in the packing parameter ( p ) during the self-assembly process. , There, p of the amphiphilic BCP gradually increases from p < 1 to p > 1 accompanied by transformation of vesicles into LCV, and ultimately, PCs and PHs. The change in p can be achieved either by in situ extension of the solvophobic block or gradual change of solvent polarity. ,− However, such an evolution would require substantial structural reorganization, with multiple fusion and fission events occurring simultaneously.…”

“…Polymer cubosomes (PCs) and polymer hexosomes (PHs) represent a class of self-assembled block copolymer (BCP) microparticles that are porous and feature a lattice of solvent-filled channels with regular order, large surface area per volume, and high loading capacity. − Research on PCs was inspired by lipid cubosomes that are formed by a particular family of liquid-crystalline lipids, such as monoolein with a packing parameter p > 1. − While lipid versions have proven useful in bio- and nanomedicine, − the chemistry of applicable lipids is rather limited and lacks tunability. In contrast, BCPs can be tuned and tailored with respect to a plethora of properties ( e.g., molecular weight, polymer architecture, block composition, and monomer chemistry), − all of which can be conferred into the resulting PCs. For instance, PCs with gated nanopores and high specific protein adsorption capacity were produced from poly­(acrylic acid)- block -polystyrene .…”

Intrinsic and Dynamic Heterogeneity of Nonlamellar Lyotropic Liquid Crystalline Nanodispersions

“…It is clear that materials choice, characteristics, and purity have a major impact on formulation heterogeneity. As such, some studies have utilized branched-linear diblock copolymers such as those composed of a hydrophilic triarm PEG and a hydrophobic polystyrene to generate polymer cubosome colloidal particles. , Morphologically, polymer cubosomes appear more homogeneous than lipid cubosomes, at least when visualized under an electron microscope. They have also higher mechanical and chemical stabilities than lipid cubosomes .…”

“…Notably, their internal liquid crystalline architectures with greater lattice parameters (by at least 1 order of magnitude than their lipidic analogues) can be adjusted to tune in a controllable manner their nanochannels and pore sizes by altering the molecular weights of their main molecular building blocks . Thus, they can provide inherent structural networks for a high loading of macromolecules, which is currently difficult to achieve due to the narrower nanochannels (4–6 nm) of the lipidic analogues. , Nevertheless, little attention has been paid toward polymer cubosomes (or hexosomes) in the development of drug delivery systems. , There is neither information on their behavior and involved phase transitions on exposure to the biological milieu nor information on their safety and biodegradation. Furthermore, it is not clear whether micelles coexist in such dispersions.…”

Prismatic Block Copolymer Hexosomes

“…BCPs, on the other hand, can be tuned in block chemistry, block length, and length ratio, opening ample possibilities to tune the pore size, lattice symmetry, and functionality of BCP cubosomes. − Some of the early and thoroughly discussed examples are BCP cubosomes from dendritic (PEO 7 ) 6 - b -PS, which allowed fine tuning of p in aqueous solution into double primitive cubic ( Im 3 m ) and diamond lattices ( Pn 3 m ) as well as inverse hexagonal channels ( P 6 mm ) within spherical microparticles. − However, it was demonstrated soon after that BCP cubosomes can also be generated from linear PEO- b -PS with proper block asymmetry (i.e., f solvohobic > 90 wt %), still providing the same level of control over particle size and lattice . While BCP cubosomes have since then been equipped with advanced properties through monomer functionality, e.g.…”