Effect of hydrogel coating of smooth muscle cells orientated on a biomaterial surface: A protective outer layer for a cellularized vascular prosthesis with surface guidance

摘要

Introduction: There is currently the need for an effective small diameter vascular prosthesis for bypass grafting. It is widely believed that such a device would benefit from fabrication with biodegradable polymers and cellularization with vasoresponsive vascular cells. Moreover, the vascular smooth muscle cells (SMCs) may benefit from topographical guidance by aligned features such as grooves or channels, these aid the preservation of the SMC contractile phenotype. We are able to print features that generate circumferential channels onto a potential polycaprolactone (PCL) vascular prosthesis that align SMCs towards the desired orientation. However to protect externally seeded cells and to cushion the implanted device against host tissues, it was proposed that the construct should be coated in a protective hydrogel. Yet little has been reported on the effects of hydrogel coating of pre-seeded cells, especially in relation to their orientation and viability following the hydrogel crosslinking reactions. The fate of cells that became detached and suspended in the hydrogel was also examined. Method: PCL films were printed with aligned PCL features using an automated robotic dispensing system thus generating SMC aligning features. SMC were seeded onto the surface. The seeded SMCs were either coated with polyethylene glycol) diacrylate (UV crosslinked) or a gelatin (transglutaminase) hydrogel. The cell surface coverage and alignment were observed and viability post coating was measured. The surface retention and degradation rates of the hydrogel were also examined. Results and Discussion: Crosslinking to the PCL surface greatly improved the surface retention of both hydrogel. However, the gelatin hydrogel coating technique allowed greater cell attachment and alignment Moreover, the gelatin hydrogel proved to be more stable than PEGDA gel in the presence of serum. This study demonstrated gelatin hydrogels have several advantages over PEGDA ones. One main factor may be due to the gelatin hydrogel retaining the ideal "cell friendly* properties of collagen, from which gelatin is derived from.