Micropatterned Styrene-Butadiene-Styrene Thin Films Doped with Barium Titanate Nanoparticles: Effects on Myoblast Differentiation.

Biohybrid actuators exploit the contraction of biological components (muscle cells) to produce a force. In particular, bottom-up approaches use tissue engineering techniques, by coupling cells with a proper scaffold to obtain constructs undergoing contraction and guaranteeing actuation in biohybrid devices. However, the fabrication of actuators able to recapitulate the organization and maturity of native muscle is not trivial. In this field, quasi-two-dimensional (2D) substrates are raising interest due to their high surface/thickness ratio and the possibility of functionalizing their surface. In this work, we fabricated micropatterned thin films made of poly(styrene-butadiene-styrene) (SBS) doped with barium titanate nanoparticles (BTNPs) for fostering myogenic differentiation. We investigated material concentrations and fabrication process parameters to obtain thin microgrooved films with an average thickness below 1 μm, thus featured by a relatively low flexural rigidity and with an anisotropic topography to guide cell alignment and myotube formation. The embodiment of BTNPs did not significantly affect the film's mechanical properties. Interestingly, the presence of BTNPs enhanced the expression of myogenic differentiation markers (i.e., MYH1, MYH4, MYH8, and ACTA1). The results show the promising potential of SBS thin films doped with BTNPs, opening avenues in the fields of biohybrid actuation and skeletal muscle tissue engineering.