Development of cell-selective films for layered co-culturing of vascular progenitor cells

Cell-sheet assemblies are currently being studied for tissue engineering. However, tissues engineered from completely biological cell sheets lack substrate cues and possess poor mechanical strength. Recent studies demonstrate the use of synthetic bioresorbable films as scaffolds that may address these issues. Here, we describe the application of a micro-thin, biaxially-stretched polycaprolactone (μXPCL) with surface modifications for layered tissue engineering, and present the results of biphasic cell-sheet constructs using surfaces optimised for specific cell types. Polyacrylic acid (PAAc) was grafted onto μXPCL film surfaces by low-pressure plasma immobilisation. This provided a surface suitable for perivascular cells, forming the medial compartment. Subsequently, endothelial progenitor cell (EPC)-selective CD34 antibody was conjugated onto the reverse surface (intimal compartment) to select and anchor EPCs for improved adhesion and proliferation. Using the blood vessel as a model, a biphasic culture system was then setup to represent a tunica intima (endothelial cells) and tunica media (smooth muscle cells). When suitable cell types were cultured in the corresponding compartments, confluent layers of the respective populations were achieved distinctively from each other. These results demonstrate the use of μXPCL films with cell-selective modifications for layered co-cultures towards the generation of stratified tissue.