Complex coacervate‐based materials for biomedicine

Abstract

There has been increasing interest in complex coacervates for deriving and transporting biomaterials. Complex coacervates are a dense, polyelectrolyte-rich liquid that results from the electrostatic complexation of oppositely-charged macro-ions. Coacervates have long been used as a strategy for encapsulation, particularly in food and personal care products. More recent efforts have focused on the utility of this class of materials for the encapsulation of small molecules, proteins, RNA, DNA, and other biomaterials for applications ranging from sensing to biomedicine. Furthermore, coacervate-related materials have found utility as in other areas of biomedicine, including cartilage mimics, tissue culture scaffolds, and adhesives for wet, biological environments. Here, we discuss the self-assembly of complex coacervate-based materials, current challenges in the intelligent design of these materials, and their utility applications in the broad field of biomedicine.

Conformation-Directed Formation of Self-Healing Diblock Copolypeptide Hydrogels via Polyion Complexation

“…7,9,10 To test this hypothesis, a new copolypeptide component, (M O A) 155 ( rac -E) 60 , was prepared, where the rac -E segment was composed of racemic residues that should inhibit β -sheet formation in PICs. 5–7,22 When equivalent amounts of (M O A) 155 ( rac -E) 60 and (M O A) 155 K 60 were mixed (total 5.0 wt % in 1× PBS), the resulting sample did not form a hydrogel and gave only a low-viscosity liquid (see the Supporting Information, Figure S15). This result confirmed the importance of chirality in the formation of the (M O A) 155 E/K 60 hydrogel structure.…”

“…1–3 In particular, assemblies containing peptides and polypeptides often take advantage of hydrophobic and H-bonding interactions between ordered chain conformations in these molecules, e.g., α -helices and β -strands, to produce materials with advantageous properties, such as defined morphology or enhanced stability. 4 Polypep-tide-containing block copolymer assemblies, such as micelles, vesicles, and hydrogels, have also been prepared using polyion complexes (PIC), 5,6 where oppositely charged chain segments aggregate and phase separate upon mixing in aqueous media. In these systems, as well as those based on other synthetic polymers, formation of unstructured, liquid PIC coacervate domains is common and often desired.…”

Weak bond-based injectable and stimuli responsive hydrogels for biomedical applications

“…73, 74 Although the complex coacervate is also an important drug delivery system for biomedical applications, it will not be included in this review and readers can refer to several recent publications for their interesting applications. 75, 95–100 To use a synthetic polyelectrolyte to form a hydrogel, an ABA triblock copolymer architecture is used. 78, 101 Fig.…”

Sodium Salicylate Mediated Ionic Liquid Based Catanionic Coacervates as Membrane‐Free Microreactors for the Selective Sequestration of Dyes and Curcumin

“…The properties and so the applications of the coacervates could be tailored through judicious selection of various solution conditions such as ionic strength, pH, temperature, electrolyte concentration, and also the molecular architecture of the electrolytes . Various applications such as purification of proteins, waste water treatment, sequestration of drugs, dyes and molecules with varied polarity, various formulations also depend on the above mentioned parameters . Keating and her co‐workers have explored RNA aptamer and ribozyme activities within the polymeric complex coacervates .…”

“…Surfactant based liquid‐liquid phase separation, i. e. coacervation is among the new age techniques to sequester the charged dyes. Coacervate based systems are used in food industry, cosmetics, to encapsulate and deliver dyes, ‐drugs, ‐genes, ‐proteins, in protocell formation, as protocell assembly to name a few . Garenne et.al examined the sequestration of more than 30 cationic, anionic and zwitter‐ionic dyes within the coacervates according to its surface charge density .…”