Designing Rules for protein encapsulation into complex coacervate core micelles (C3M)

Abstract

Inside cells, proteins and other biomolecules functions depend not only on their intrinsic characteristics, but also on the properties of the environment, like viscosity, water content and other related phenomena. However, it is curious that biomolecules remain stable and active inside the cell, but that outside this environment, they usually need special conditions to ensure their functionality (generally performed in dilute solutions, minimizing those non-specific interactions, to retain enzymatic activity). In this sense, one of our main challenges is to understand the effects related to the stabilization of enzymes and manage to obtain a system that mimics such intracellular conditions. The coacervate phase is formed by a large water content (typically, 65-85%), some simple ions, as well as polyelectrolytes, so they mimic very well the intracellular environment. Coacervates can be confined into a nanometric domain if one of the coacervate components is constituted by a charged-neutral diblock copolymer. The strategy of using C3Ms for protein encapsulation has great relevance both in terms of stability and activity of the protein in solution. So, the main objective of this project is to investigate the effect of polyelectrolyte and neutral block lengths, pH, ionic strength, and charge patchiness on the encapsulation efficiency of proteins inside C3Ms. The systems will be characterized using mainly light scattering (LS) and small angle x-ray scattering (SAXS) techniques. In this sense, elucidating these details, will allow the determination of the general rules for biomolecule encapsulation into nanometric aggregates. Thus, although this project seeks answers to fundamental questions, our results will offer predictive tools to effectively design encapsulation strategies for novel targets. The expertise of Professor Sarah Perry's group at the University of Massachusetts Amherst will guide to encapsulate proteins and to define these rules. (AU)