Piezoionic response in PEGDMA and GelMA hydrogels : From bulk characterisation to microchip integration

Details

Supervisors

Demoustier-Champagne, Sophie ; Van Ruymbeke, Evelyne

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical, à finalité spécialisée

Abstract

enSkeletal muscle tissue engineering (TE) requires biomaterials that can replicate the mechanical and electrical stimuli present in native muscle. One key challenge lies in recreating the tissue’s intrinsic mechanoelectrical environment, which plays a crucial role in muscle function and coordination. Piezoionic hydrogels– a class of materials capable of converting mechanical deformation into ion flux– offer a self-powered approach to mimicking this dynamic signalling. In this thesis, primarily PEGDMA-based formulations were developed and characterised. Three distinct strategies were used to induce piezoionicity: (i) copolymerisation with an ionic monomer– either the anionic 3-sulfopropyl methacrylate potassium (SMP), the cationic [2-(methacryloyloxy)ethyl]trimethylammonium chloride (METAC) or the zwitterionic [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (MASA); (ii) immersion in salt solutions of KCl, NaCl, or LiCl; and (iii) a combination of both approaches. Gel fraction, swelling ratio and rheological measurements were first performed to characterise the physical properties of the hydrogels and provide context for interpreting differences in their piezoionic responses. The piezoionic behaviour was then evaluated by quantifying the generated ionic potential under controlled mechanical stimulation. Piezoionic coefficients were derived to compare the effectiveness of each strategy. Results showed that incorporating ionic monomers into the formulation led to the strongest response, with coefficient reaching 22.8 nV Pa−1 for PEGDMA 10 w/v% combined with 25 mol% of METAC. Additionally, GelMA based systems were explored due to their greater biological relevance, enabling a preliminary assessment of piezoionic behaviour in more biomimetic conditions. These GelMA-based samples exhibited even higher piezoionic activity, with coefficients reaching 105.5 nV Pa−1. Finally, a limited number of formulations were tested within a microfluidic chip to investigate piezoionic responses in a confined environment. Remarkably, a piezoionic coefficient of 10.65 nV Pa−1 was successfully observed. To our knowledge, this represents one of the first successful demonstrations of piezoionic signals within a microfluidic chip, highlighting the potential of this approach for dynamic bioelectronic applications.