Bioinspired Processing ofComplex Coacervates forAdvanced Materials

Complex coacervation is an associative liquid-liquid phase separation phenomenon driven by electrostaticattraction between oppositely charged macro-ions (e.g. polysaccharides, proteins etc.) and counter-ionrelease, resulting in a polymer rich aqueous phase in equilibrium with a polymer poor phase [1]. For a givenpolyelectrolyte couple, depending on the salt concentration of the medium, a complex coacervate eitherbehaves as a free-flowing viscoelastic fluid or a rigid polyelectrolyte complex or anything in between [2].This outstanding versatility has made complex coacervates good candidates for a wide range of applications[3]. In the Kamperman group at the Zernike Institute for Advanced Materials at the University of Groningen,we are dedicated to improve and engineer complex coacervates to introduce novel advanced functionalmaterials such as underwater adhesives [4], double network hydrogels, 3D printing biomaterial inks andresponsive Pickering emulsifiers micelles.
In this presentation, I will particularly focus on the use of hyaluronic acid – chitosan complex coacervate as abiomaterial ink for 3D printing. By carefully optimizing, the physico-chemical parameters of the system,meaning pH, salinity and molecular weight of the polymers, we were able to produce a set of biomaterialinks that can be used in different environmental conditions. The developed inks can not only be dried andre-hydrated without loss of shape fidelity, but also be printed into a liquid medium (fresh-printing) withoutthe need of any chemical modification or post-printing curing process. These promising results show thepotential of coacervate-based biomaterial inks to be used as 2D and 3D scaffolds in cell culture studies.