Chitosan/vanillin/polydimethylsiloxane scaffolds with tunable stiffness for muscle cell proliferation.

The mechanical properties of scaffolds can significantly influence cell behavior. We propose a methodology for producing chitosan and vanillin-crosslinked chitosan films with tunable mechanical properties to be applied as scaffolds for C2C12 myoblasts. In this approach, aqueous polydimethylsiloxane (PDMS) elastomeric dispersions were prepared using polysorbate 20 as emulsifier. These dispersions were then cured and incorporated into chitosan or vanillin-crosslinked chitosan polymeric dispersions at two different volume fractions (1 % and 10 %), followed by casting into films. Atomic force microscopy in force spectroscopy mode was used to characterize the mechanical properties of the swollen systems in PBS buffer. The mechanical properties of the chitosan and vanillin-crosslinked chitosan scaffolds were modulated by the incorporation of the elastomer. The elastic modulus (E) of chitosan-based scaffolds varied from 60 to 200 kPa, while for vanillin-based scaffolds, it ranged from 200 to 600 kPa with the addition of PDMS elastomers. A general trend observed was that the softest scaffolds exhibited the highest swelling degree and the lowest gel content. After 24 h, good cell viability was observed for chitosan and chitosan-PDMS scaffolds, whereas vanillin-based scaffolds showed borderline cytotoxicity (∼70 %). C2C12 cells demonstrated good adhesion on scaffolds with E values ranging from 114 to 568 kPa.