Liquid crystal elastomer foams with elastic properties specifically engineered as biodegradable brain tissue scaffolds

Abstract

Tissue regeneration requires 3-dimensional (3D) smart materials as scaffolds to promote transport of nutrients. To mimic mechanical properties of extracellular matrices, biocompatible polymers have been widely studied and a diverse range of 3D scaffolds have been produced. We propose the use of responsive polymeric materials to create dynamic substrates for cell culture, which goes beyond designing only a physical static 3D scaffold. Here, we demonstrated that lactone- and lactide-based star block-copolymers (SBCs), where a liquid crystal (LC) moiety has been attached as a side-group, can be crosslinked to obtain Liquid Crystal Elastomers (LCEs) with a porous architecture using a salt-leaching method to promote cell infiltration. The obtained SmA LCE-based fully interconnected-porous foams exhibit a Young modulus of 0.23 ± 0.07 MPa and a biodegradability rate of around 20% after 15 weeks both of which are optimized to mimic native environments. We present cell culture results showing growth and proliferation of neurons on the scaffold after four weeks. This research provides a new platform to analyse LCE scaffold-cell interactions where the presence of liquid crystal moieties promotes cell alignment paving the way for a stimulated brain-like tissue.

Advances in Cell Scaffolds for Tissue Engineering: The Value of Liquid Crystalline Elastomers

“…After solvent removal and crosslinking completion, template removal results in 3D scaffolds showing a complementary morphology with respect to the templates. Notably, to the best of our knowledge, these last 3D samples present polydomain structures because no alignment procedures are applied during the crosslinking, and the shape‐changing behaviour of these samples has not been yet investigated …”

“…d) Schematization of the salt‐template etching process to prepare LCE foams to be used as scaffolds from brain cell, and confocal image ( x , y ‐ and x , z ‐plane) obtained in LCE foams (green) after 30 days (right) showing cell proliferation; Adapted from ref. with permission of The Royal Society of Chemistry, Copyright (2018). e) Orientation maps obtained by imageJ of C2C12 and hDF seeded on a LCE or on a Petri dish (20× lens magnification).…”

“…Removal of the salt (by leaving the foam in water for 3 days) followed by drying, leads to the 3D foam scaffolds. The as‐prepared scaffolds were demonstrated to support in vitro neuronal growth by seeding SH‐SY5Y …”

“…Notably,t ot he best of our knowledge,t hese last 3D samples present polydomain structures because no alignment procedures are applied during the crosslinking, and the shapechanging behaviour of these samples has not been yet investigated. [57,58]…”

3D Porous Liquid Crystal Elastomer Foams Supporting Long‐term Neuronal Cultures

“…The process, allows for control of pore size, density, and morphology 17,20. Highly interconnected pores (>85%21) provide suitable mass transport where cells have constant access to nutrients, gases, and waste management, reducing cell death and increasing viability,35 avoiding mass transfer restrictions,36 where diffusion of nutrients, and oxygen are promoted by the scaffold structure. The presence of LC moieties promote cell attachment and proliferation, as well as orientation and anisotropic cell growth,19 allowing the creation of neural networks in organized patterns to serve specific functions and that mimicking endogenous systems.…”