Human Mesenchymal Stromal Cell Enhanced Morphological Polarization by Contact Interaction with Polyethylene Terephthalate Nanogratings

Understanding how the substrate topography acts on human bone marrow-derived mesenchymal stromal cells (MSCs) can help the rational design of scaffolds for improving bone regeneration protocols. MSCs are highly sensitive to the extracellular physical properties and can be successfully manipulated by simple contact interaction with supporting substrates. To this end, some polymeric materials were introduced, but polyethylene terephthalate (PET), a thermoplastic polymer approved by the US Food and Drug Administration for clinical use and very attractive in terms of biocompatibility and mechanical properties, has not been tested yet in terms of cell mechanotransduction. Here, we propose PET nanogratings (alternating lines of submicron ridges and grooves) as scaffolds for stimulating mechanotransduction mechanisms. Low-temperature hot embossing is exploited as fabrication method, and standard oxygen plasma activation as functionalization to improve cell adhesion and spreading. We show that the substrate directionality stimulus is optimally delivered to the MSCs, which in turn elongate and align to the nanograting lines. Finally, we verify that this polarization occurs also at level of cytoskeleton fibers and, though to a lesser extent, of nuclei.