Small Amphiphile‐Based Coacervation

Abstract

Coacervation plays an important role in the molecular assembly towards soft materials with a diversity of function (e. g., underwater adhesives of mussels and membraneless organelles). Coacervation is observed when one homogenous solution spontaneously separates into two immiscible liquid phases of low and high solute concentration, also known as liquid-liquid phase separation (LLPS), which enables spatiotemporally local concentration of specific molecules. LLPS is a common physical phenomenon in aqueous solutions of polyelectrolytes, surfactants and biomolecules, which has been extensively explored for applica-tions in the fields of environmental remediation, cosmetic formulation, protein purification, extractive fermentation and pharmaceutical microencapsulation. This review summarizes the development of LLPS with low molecular weight amphiphiles to construct simple and complex coacervates using conventional surfactants and novel amphiphiles such as azobenzene-derivatives and peptides. We also highlight the applications of these amphiphile coacervates in the extraction of biomolecules, construction of protocell models and drug delivery.

Theory of self-coacervation in semi-dilute and concentrated zwitterionic polymer solutions

“…The latter is a common physical phenomenon, occurring in aqueous solutions of polyelectrolytes, surfactants, and biomacromolecules – systems that nowadays are extensively explored, both theoretically and experimentally, and have a number of applications in food, pharmaceutical, cosmetic, and chemical industries. 1 On the other hand, in the 1930s, Alexander Oparin proposed the concept of coacervation in solutions of biomacromolecules underlying the origin of life. 2 And it was not until 2009 that biophysicists established the role of liquid–liquid phase separation in the formation of certain membraneless organelles.…”

Synthetic‐Cell‐Based Multi‐Compartmentalized Hierarchical Systems

“…Recently, coacervate microdroplets were engineered as a model of artificial life-like entities to investigate the origin of protocells as well as the membraneless organelles in living cells; their common formation mechanisms included multiple weak associative interactions of differently charged polyelectrolytes through liquid-liquid phase separation. [53,55] The construction of singlephase condensates has been successfully achieved, and the formation of complex coacervate microdroplets will be an important research topic in the future. The most important aspects of multiphase complex coacervate microdroplets is the selection and integration of multiple polyelectrolytes via electrostatic interactions.…”

“…Specifically, membrane-bound compartments are engineered by employing self-assembled amphiphiles at liquid/liquid interfaces with a semipermeable membrane, including liposomes, [19][20][21][22] polymersomes, [1,23,24] fatty acid vesicles, [25][26][27][28][29][30] hyperbranched polymer vesicles, [31,32] colloidosomes, [33][34][35][36][37][38][39] proteinosomes, [40][41][42][43] polysaccharideosome, [44,45] and waterin-oil emulsion droplets. [46] The formation mechanism of membraneless compartments mainly include liquid-liquid phase separation (LLPS), [47][48][49][50][51][52][53][54][55][56][57] which are mediated via the mutual repulsion among neutral macromolecules or the electrostatic interaction among polyelectrolyte molecules. Due to the usage of different building blocks as well as engineering methods, these biomimetic compartments exhibit unique properties and various essential characteristics of living cells, including growth, [37,58] genetic behavior, [39,…”