Poly(lactic-co-glycolide) based biodegradable electrically and magnetically active microenvironments for tissue regeneration applications

Abstract

Polymer scaffolds are playing an increasing role in tissue engineering (TE), although there is still a need to improve their biomimicry of cellular microenvironments, by having smart scaffolds with an active response, which can improve tissue regeneration. This work reports on the novel combination of poly(lactic-co-glycolide) (PLGA) with the ionic liquid (IL) choline bis(trifluoromethylsulfonyl)imide ([Chol][TFSI]) or with iron oxide nanoparticles (Fe3O4, NP) in order to achieve biodegradable scaffolds with electroactive and magnetoactive response, respectively. The composites were processed into fiber and film morphologies. PLGA + IL fibers present diameters between 1.92 and 3.26 µm, decreased mechanical stiffness and elongation at yield with respect to the pristine polymer, and some fiber concentrations are not biocompatible. PLGA + IL films present a mean roughness 6.58 nm, increased mechanical stiffness with respect to the pristine polymer and decreased elongation at yield. The inclusion of IL increased the electrical conductivity of the polymer by 4 orders or magnitude.The diameter of PLGA + Fe3O4 fibers ranged from 0.62 to 1.36 µm, show an effective magnetic NP content yield between 52 and 78%, decreased stiffness and increased elongation at yield. PLGA + Fe3O4 films show a mean roughness of 5.07 nm, effective NP content yield between 77 and 97%, increased stiffness and elongation at yield. Cytotoxicity assays indicate that the PLGA + Fe3O4 materials are suitable for biomedical applications, independently of the filler content and morphology, whereas the IL containing samples are non-cytotoxic only in film morphology up to 5% wt. IL content. Finally, it is demonstrated that dynamic magneto mechanical stimulation of the PLGA + Fe3O4 samples allows the acceleration of the degradation rate of the samples.