Bioink design using polyelectrolyte complexes

Details

Supervisors

Dupont-Gillain, Christine C. ; des Rieux, Anne

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

Three dimensional bioprinting is an emerging approach aiming to construct artificial tissues that mimic the structure of native tissue by additive manufacturing using bioinks. The rheological properties of bioinks must be compromised between printability, mechanical stability, and cell viability. The set of constraints that bioinks must comply to is extensive and application-dependent, therefore many developments remain to be achieved to find suitable bioinks for each application. Polyelectrolyte complexes (PECs) are materials created by mixing two oppositely charged polyelectrolytes in solution. These PECs can form a wide array of systems, from tough glassy solids to gels, viscous solutions, and colloidal suspensions. Some have mechanical properties that are between a solid and a liquid, while a major part of their volume is water. The focus of this master’s thesis was to test combinations of polyelectrolyte complexes to obtain a material suitable for use as a bioink using a result-driven, experimental approach. Having found a suitable polyelectrolyte pair, the process of characterizing the resulting PECs then started. The objective was to refine the protocol and get quantitative data on the mechanical and structural properties of the material to assess its potential as a bioink. The obtained results have shown that this PEC is halfway between a viscous liquid and an elastic solid. It can be printed through an opening of 500µm diameter with ease and retains its shape after printing. It is stable for over a week when immersed in a phosphate buffered saline solution. Scanning electron microscopy imaging shows that the material is very porous, with pores ranging in size from 10-200µm. The mechanical properties are influenced by the molar masses of the constituents, temperature has a minor effect. The material can be ground into a powder and rehydrated to reform a hydrogel, opening up new possibilities to integrate cells within the material. This exploratory work thus opens new perspectives in the quest to print cell-based constructs, with potential benefits for regenerative medicine.