Self-Assembly of Janus Oligomers into Onion-like Vesicles with Layer-by-Layer Water Discharging Capability: A Minimalist Model

Abstract

A vesicle in a cell is an enclosed structure in which the interior fluid is encompassed by a lipid bilayer. Synthetic vesicles are known as the liposomes. Liposomes with a single phospholipid bilayer are called unilamellar liposomes; otherwise, they are called multilamellar liposomes or onion-like liposomes (vesicles). One prototype synthetic onion-like vesicle, namely, onion-like dendrimersomes, have been recently produced via the self-assembly of amphiphilic Janus dendrimers (Proc. Natl. Acad. Sci. U.S.A. 2016, 113, 1162). Herein, we show computer simulation evidence of another type of onion-like vesicle, namely, onion-like oligomersomes, via the self-assembly of amphiphilic Janus oligomers in water. Specifically, we investigate the minimum-sized oligomers (or minimalist model) that can give rise to the onion-like oligomersomes as well as the composition-dependent phase diagrams. Insights into the formation condition and formation process of the onion-like oligomersomes are obtained. We demonstrate that the discharge of the in-vesicle water is through the remarkable "peeling-one-onion-layer-at-a-time" fashion, a feature that can be utilized for a clinical dosing regimen. The ability to control the formation of onion-like oligomersomes by design can be exploited for applications in drug and gene delivery.

Multilayer onion‐like vesicles self‐assembled from amphiphilic hyperbranched multiarm copolymers via simulation

“…The other areas of the phase diagram are onion‐like micelles. The result is consistent with the simulation work reported by Arai and Zeng et al…”

“…Meanwhile, α AS = 150 can represent polymers that have similar highly hydrophobicity to the hyperbranched fluoropolymers core or dendritic aromatic hydrocarbon core . Likewise, considering it is benefit to form onion‐like vesicles with weak hydrophilicity ( α BS ≥ 30) between hydrophilic linear arms and solvents . Thus, the interaction parameter between hydrophilic linear arms and solvents ( α BS ) is chosen as 33–38, which means that the arm's affinity for solvent is changed from weak hydrophilic to hydrophobic.…”

“…Recently, computer simulations have been successfully applied to investigate the self‐assembly behaviors of polymers in solution. For example, Arai and Zeng et al constructed a simple coarse‐grained model of Janus polymer . The formation conditions of the onion‐like vesicles and the self‐assembly dynamics were studied by dissipative particle dynamics (DPD) method.…”

Amphiphilic self-assembly of semiconductor nanocrystals with heterogeneous compositions

“…Nanorods with a length of 4.72 nm and a width of 0.67 nm were placed in a simulation box with a volume of 19.4 × 19.4 × 19.4 nm 3 . Interaction parameters (in k B T ) between any two DPD beads are set as shown in table 1 based on our previous work [33,34]. These parameters were verified to successfully reproduce the self-assembling behavior of amphiphilic Janus spheres [34,35].…”

“…To elucidate that the self-assembling mechanism of CdSe nanorods indeed relies on the hydrophobic contacts between the end-surfaces, we performed a DPD simulation using an amphiphilic nanorod model [33]. The main body of the nanorod model is formed by solvophilic beads while the topmost layers of both ends are modified by solvophobic beads ( fig.…”