Magnifying the Structural Components of Biomembranes: A Prototype for the Study of the Self‐Assembly of Giant Lipids

Abstract

How biomembranes are self‐organized to perform their functions remains a pivotal issue in biological and chemical science. Understanding the self‐assembly principles of lipid‐like molecules hence becomes crucial. Herein, we report the mesostructural evolution of amphiphilic sphere‐rod conjugates (giant lipids), and study the roles of geometric parameters (head–tail ratio and cross‐sectional area) during this course. As a prototype system, giant lipids resemble natural lipidic molecules by capturing their essential features. The self‐assembly behavior of two categories of giant lipids (I‐shape and T‐shape, a total of 8 molecules) is demonstrated. A rich variety of mesostructures is constructed in solution state and their molecular packing models are rationally understood. Giant lipids recast the phase behavior of natural lipids to a certain degree and the abundant self‐assembled morphologies reveal distinct physiochemical behaviors when geometric parameters deviate from natural analogues.

Screw dislocation-induced pyramidal crystallization of dendron-like macromolecules featuring asymmetric geometry

“…[14][15][16][17][18][19][20][21][22][23][24][25] Due to the anisotropy as well as the rigid domains, they have enriched the phase diagrams by self-assembling into diverse nanostructures in the bulk, at the interface, or in solutions. 38,39,[45][46][47][48][49][50][51][52][53][54][55] The topological design featured by breaking the geometrical symmetry of MJPs has elucidated its influence on phase behaviors. 56,57 When increasing the degree of asymmetry, continuous changes in crystalline and quasicrystalline phases were achieved in bulk, indicating the influence of domain volume fractions on the interface curvatures.…”

Thermosensitive Vesicles from Chemically Encoded Lipid‐Grafted Elastin‐like Polypeptides

“…[7,8] Later developed polymersomes,b uilt from amphiphilic synthetic polymers/polypeptides,p rovided more mechanically stable vesicle structures owing to macromolecules of higher molar mass and thicker membranes (5-50 nm). [8][9][10][11] Recent advances in cell-mimicking systems have drawn the attention to genetically encoded protein/peptide-based membrane forming bioamphiphiles for potential design of artificial living systems with self-replication, growth and division properties. [6,[12][13][14] Among proteins of interest, elastin-like polypeptides (ELPs) have been proposed as arelevant class of intrinsically disordered proteins (IDPs).…”

“…Considering the average 60 % [6] lipid composition of natural membranes (such as cholesterol, phospholipids, glycerophospholipids, sphingolipids ) , the first basic synthetic analogues of biological cells reported are liposomes prepared from naturally occurring phospholipids and composed of a 3–5 nm thick bilayer membrane [7, 8] . Later developed polymersomes, built from amphiphilic synthetic polymers/polypeptides, provided more mechanically stable vesicle structures owing to macromolecules of higher molar mass and thicker membranes (5–50 nm) [8–11] …”

Self-Assembly Behaviors of Giant Amphiphiles Containing Cubic Cage-like “Monomers”

“…Besides the chemical amphiphile in these molecules, there are also size and shape amphiphiles. 66,67 Cheng and co-workers have ingeniously designed and synthesized various amphiphilic molecules composed of polyhedral oligomeric silsesquioxane (POSS) 9,[11][12][13][14][15][16][17]19,20,41,46 or fullerene (C 60 ) 8,10,18,21,46,51,68 tethered by one or a few polymeric chains and called them "giant surfactants". 9 These giant surfactants exhibit a lot of interesting self-assembly behaviors.…”

“…Each part can be composed of several molecular groups, clusters, liquid crystals, polymers, and even nanoparticles. Accordingly, there are many different amphiphiles, such as traditional small-molecule surfactants, − giant surfactants, − amphiphilic liquid crystals, − block copolymers, − polymer-tethered nanoparticles (tadpole), − and patchy nanoparticles (e.g., Janus). − In addition to the two common factors, the volume fraction of one part, and the immiscibility between two dissimilar parts, the self-assembly of amphiphiles is significantly affected by the intrinsic properties of their constituent parts, i.e., size and shape (geometry or topology). ,,,,− For instance, the AB-type block copolymers are one typical kind of self-assembly amphiphiles, and their self-assembly behaviors can be largely tuned by tailoring their chain architectures. − The simplest AB diblock copolymer can self-assemble into a body-centered cubic (BCC) lattice of spheres, a hexagonal array of cylinders, double gyroid, and lamellae as the volume fraction of A block ( f ) increases from 0 to 0.5 . If a single B block of AB diblock is replaced by multiple branched B blocks to form AB n miktoarm star copolymer, significantly different self-assembly behavior can be obtained. − ,− Since the divided short B blocks are stretched more severely than the A block, the spontaneous curvature of the A/B interface bending toward the A domain is increas...…”