PhD Student Institute of Cytology Russian Academy of Science, Russia
Abstract: Control of cell behavior is essential for regulating the process of tissue regeneration. We aim to direct cells to adhere, migrate and proliferate predictably ultimately leading to the formation of new tissue and topology appears to be a very impactful signal for this process. Yet it is still unclear how the microtopology of such a widely used polymer as poly-ɛ-caprolactone (PCL) affects the cell behavior. PCL is a semicrystalline polymer and upon its surface distinct crystals known as spherulites form, giving rise to a topology with an as-yet unidentified influence on cell activity. So, we have developed two different types of PCL scaffolds with elaborate topology. The first one exhibits a variable area and height of PCL spherulites varying in the surface roughness from 50 to 220 μm and the median area from 100 to 700 μm2, depending on the production conditions. The second one features pore-like structures with diameter less than 0.5 μm, which arise in blend scaffolds from the dissolution of added polyethylene glycols (PEG) with molecular mass ranging from 1 to 15 kDa. It has been shown that fetal mesenchymal stem cells (MSCs) tend to adhere more actively to higher spherulites while proliferating extensively on the flatter ones. Moreover, migration patterns are more pronounced and rapid on the latter as well. Due to the surface tension, MSCs are more spread out on the higher roughness scaffolds, but there is no significant difference in average circularity. On the pore-like surfaces, the presence of leftover hydroxyl groups from PEG favorably affects cell behavior due to an increase in the hydrophilicity of the surface, but the high surface roughness offsets it. PEG 6kDa shows the lowest contact angle so MSCs prefer it more for both adhesion and proliferation. However, pores contribute to these processes and boosts them as well. So, this study underscores the significance and the effect of PCL surface topology for MSCs behavior and in the tissue engineering constructions fabrication.
