Temporally Programmed Disassembly and Reassembly of C3Ms

Abstract

Responsive materials, which can adapt and operate autonomously under dynamic conditions, are a stepping stone towards functional, life-like systems inspired by fueled self-assembly processes in nature. Complex coacervate core micelles (C3Ms) comprising oppositely charged macromolecules constitute a novel class of polymeric micelles ideally suited for use as responsive nanoscopic delivery vehicles of hydrophilic and hydrophobic cargo. To fully exploit their potential, it is important that the C3Ms form and fall apart in an autonomous fashion as orchestrated by dynamic cues in their environment. Herein a means to temporally program the self-regulated C3M coassembly pathway, using a modulated base-catalyzed feedback system, is presented. Incorporated in the C3Ms is a pH responsive polyfluorene-based conjugated polyelectrolyte (CPF) as a building block and trace amounts of a molecular sensor (doxorubicin HCl) as cargo, both of which report on micellar coassembly and disassembly via binding-induced fluorescence quenching. CPF additionally reports on the pH of its microenvironment as its pH-dependent conformational states are mirrored in the transitions of its vibronic bands. This experimental design enables one to monitor solution pH, C3M disassembly and reassembly, as well as cargo release and recapture noninvasively in a closed system with real time florescence experiments.

On Complex Coacervate Core Micelles: Structure-Function Perspectives

“…To demonstrate the proof-of-principle, C3Ms have been exposed to controlled environments, which were induced to undergo an autonomous variation in the solution pH through the production of either base or acid, to disassemble and assemble the C3Ms within a predesignated timeframe reversibly. Specifically, C3Ms consisting of poly( N -methyl-2-vinylpyridinium iodide copolymer (PM2VP- b -PEO) and poly [9,9′-bis(3′-sodium propanoate)fluoren-2,7-yl] (cPF) were prepared at high pH in the presence of the enzyme urease, loaded with Dox, and programmed for transient disassembly by means of the urease-catalyzed hydrolysis of urea [ 153 ]. The water-soluble, conjugated polyelectrolyte cPF was negatively charged in the initial basic solution and, thus, complexed with the positively charged block copolymer.…”

Active coacervate droplets as a model for membraneless organelles and protocells

“…Numerous synthetic complex coacervate-based droplets exist, [11][12][13][14][15][16][17][18] which are used to investigate the characteristics of membraneless organelles. 19,20 Examples of reversible complex coacervate droplets have been reported that form or dissolve upon a change in pH, 21 temperature, 19 salt or polymer concentration, 19,22 or in response to UV light 23 or an enzymatic reaction [24][25][26] . These models provide valuable information on the formation or dissolution of droplets.…”

KNCV Gold Medal: I. K. Voets / SBIC Early Career Award: A. Dey / Malcolm McIntosh Prize: E. J. New / ICS Excellent Young Scientist Prize:C. E. Diesendruck

“…Voets seeks to understand how complex functionalities emerge from hierarchical self‐organization processes in (biological) soft matter, aiming ultimately to design, manufacture, and apply innovative lifelike materials. She was among the authors of a Communication in Angewandte Chemie on strain stiffening hydrogels and a Communication with inside back cover in Small on the programmed disassembly and reassembly of complex coacervate core micelles …”