Elastin-like Polypeptide Diblock Copolymers Self-Assemble into Weak Micelles

Abstract

The self-assembly of synthetic diblock copolymers has been extensively studied experimentally and theoretically. In contrast, self-assembly of polypeptide diblock copolymers has so far been mostly studied experimentally. We discovered that the theory developed for synthetic diblock copolymer does not fully explain the self-assembly of elastin-like polypeptide diblock copolymers, leading us to generalize the theory to make it applicable for these polypeptides. We demonstrated that elastin-like polypeptide diblocks self-assemble into weak micelles with dense cores and almost unstretched coronas, a state not previously observed for synthetic diblock copolymers. Weak micelles form if the surface tension at the core–corona interface is low compared to that expected of a micelle with a dense core. The predictions of the theory of weak micelles for the critical micelle temperature, hydrodynamic radius, and aggregation number of elastin-like polypeptide diblocks are in reasonable agreement with the experimentally measured values. The unique and unprecedented control of amphiphilicity in these recombinant peptide polymers reveals a new micellar state that has not been previously observed in synthetic diblock copolymer systems.

Programming molecular self-assembly of intrinsically disordered proteins containing sequences of low complexity

“…Here we converted the molar concentration of the solution of ELP to volume fraction ϕ by using a pentapeptide molar mass of M = 427 g mol −1 (the mass of one Val-Pro-Gly-Val-Gly pentapeptide) and an ELP mass density of ρ = 1 g cm −3 (ref. 24). The data in Fig.…”

“…It is important that ELPs undergo simple coacervation—driven by a preference for homotypic self-interactions over protein–solvent interactions—as opposed to charge-mediated complex coacervation, in which oppositely charged species form coacervates in solution 19 . The relationship between the molecular parameters of a diverse family of ELPs—their guest residue, chain length and block architecture—and their aqueous solubility is well characterized as a function of temperature, concentration and the presence of cosolutes 18,20–24 .…”

Recombinant Synthesis of Hybrid Lipid–Peptide Polymer Fusions that Self‐Assemble and Encapsulate Hydrophobic Drugs

“…However, consistent with previous reports of ELP micelles, the magnitude of A 2 for all constructs was very small and can safely be neglected in calculating N agg . [16] …”

Modular protein domains: an engineering approach toward functional biomaterials

“…In addition, spherical structures of ELPs have been triggered by the thermo-responsive behavior [11]. Structures formed by ELPs include hollow spheres or spheres with a dense core, and their size distributions can be controlled by salt concentration [12] or by the number of repeating units [13]. ELP spheres have been used as templates for nanoparticle synthesis [14] and have been applied to other applications, such as drug delivery vehicles [15].…”