Abstract
Tissue engineering by self-assembly offers the possibility to fabricate contiguous cell sheets that are stabilised by intact cell-cell contacts and endogenously produced extracellular matrix (ECM) However, these systems lack the possibility to introduce topographical cues, that are fundamental for the organisation of many types of tissues. Herein we venture to fabricate aligned electrospun thermoresponsive nanofibres to sustain growth and detachment of ECM-rich living substitutes in the presence of a MMC microenvironment. A copolymer of 85% poly-N-isopropylacrylamide and 15% N-tert-butylacrylamide (pNIPAAm/NTBA) were used. To create aligned nanofibers, the polymer was electrospun and collected on a mandrel rotating at 2000 rpm. Human adipose derived stem cells (hADSC) were treated with media containing macromolecular crowders to enhance matrix deposition. Cell viability and morphology were assessed, and immunocytochemistry was conducted to estimate matrix deposition and composition. Non-invasive cell detachment was enabled by decreasing the temperature of culture to 10 °C for 20 minutes. The electrospinning process resulted in the production of pNIPAm/NTBA fibres in the diameter range from 1 to 2 µm and an overall alignment of 80%. Cell viability revealed that hADSCs were able to grow on the scaffold. The cells aligned on the fibres after 3 days and they were able to detach as intact cell sheets in presence of MMC. Moreover, it was demonstrated that MMC, by a volume extrusion effect, enhances collagen type I deposition, one of the main components of the ECM. Collectively the pNIPAm/NTBA fibres were able to successfully sustain growth and detachment of ECM-rich cell sheets.
