Effect of L-Ascorbic Acid and All-trans Retinoic Acid on Smooth Muscle Cells Cultured on PCL Scaffolds

The aim of vascular tissue engineering (VTE) is to fabricate tissues that are both mechanically and biologically competent similar to the native vessel they are intended to replace. To this end, the incorporation of sufficient extracellular matrix elastin and collagen is important. The objective of this thesis work was to evaluate the effect of two biochemical factors, L-ascorbic acid (AA) and all-trans retinoic acid (atRA), on elastin synthesis when coronary artery smooth muscle cells were cultured on 3D polycaprolactone (PCL) scaffolds. First, porous PCL scaffolds were fabricated using a solvent casting and particulate leaching approach. The effect of different solvents (ethyl acetate, chloroform and tetrahydrofuran) and PCL concentration on the morphology and porosity of the resulting scaffolds were studied. The best scaffolds (based on SEM and micro-CT analyses) were fabricated from 30% w/w PCL in ethyl acetate. Second, smooth muscle cells were cultured on these scaffolds to evaluate elastin synthesis. It was found that concurrent addition of AA and atRA in both 2-D and 3-D cultures suppressed elastin protein expression compared with atRA alone. To overcome this effect, sequential biochemical factors addition was tested. The results demonstrated that sequential but not concurrent addition of biochemical agents promoted tropoelastin synthesis. This study suggested the importance of biochemical factor addition strategy to engineer a viable vascular tissue.