Smart hydrogels for drug-delivery and bioprinting applications

Hydrogels are attracting enormous attention in nanotechnology because of their perceived intelligent behaviour and peculiar physical properties. For instance, they can be utilized as three-dimensional scaffolds where living cells are embedded in a biomimetic environment. In this framework, bioprinting technologies allow to design and realize novel scaffolds paradigms. During and after bioprinting, the hydrogel must undergo physicochemical processes for stabilizing the printed part from the mechanical point of view. For instance, chemical cross-linking can be used. In this case, a complex chemo-mechanical system is obtained, where inelastic deformations couple with internal chemical mechanisms, such as volume shrinking due to crosslinking chemical reactions and/or swelling due to fluid motion of the solvent in the polymer network.

Additionally, the novel physical properties of hydrogels can be also exploited in drug delivery applications. As a matter of fact, hydrogel porosity is capable of loading the drugs into the gel matrix. Their porous microstructure can be tuned by regulating the density of crosslinkers in the gel matrix and the affinity of the hydrogels for the aqueous environment in which they are swollen. Consequently, the drug will be released at a rate and with an amount depending on crosslinking action.

In this framework, the aim of this project is to:

• Develop a chemo-mechanical model of hydrogels accounting for the coupled action of shrinking (induced by crosslinkers) and swelling (related to fluid motion).
• Develop a computational framework based on a finite element discretization of the coupled chemo-mechanical system.
• Apply the developed framework for the analysis of pharmacokinetic in drug delivery systems.
• Apply the developed framework for predicting the final geometry, printing fidelity and internal stresses of bioprinted tissue engineering scaffolds as function of bioprinting protocols.
• Develop a multiscale submodelling approach for estimating cell micromechanical environment, and hence cell stimuli and survival rates, following bioprinting

This project is carried out within the framework of the Masterplan SMART BIOTECS, alliance between the Technical University of Braunschweig and the Leibniz University of Hannover. This initiative is financially supported by the Ministry of Science and Culture (MWK) of Lower Saxony, Germany.