Expansion of fibroblast cell sheets using a modified MEEK micrografting technique for wound healing applications

Cell sheet engineering, a scaffold-free approach to fabricate functional tissue constructs from several

cell monolayers, has shown promise in tissue regeneration and wound healing. Unfortunately, these

cell sheets are often too small to provide sufficient wound area coverage. In this study, we describe

a process to enlarge cell sheets using MEEK micrografting, a technique extensively used to expand

skin autografts for large burn treatments. Human dermal fibroblast cell sheets were placed on MEEK’s

prefolded gauze without any use of adhesive, cut along the premarked lines and stretched out at

various expansion ratios (1:3, 1:6 and 1:9), resulting in regular distribution of many square islands of

fibroblasts at a much larger surface area. The cellular processes essential for wound healing, including

reattachment, proliferation, and migration, of the fibroblasts on expanded MEEK gauze were superior

to those on nylon dressing which served as a control. The optimal expansion ratio with the highest

migration rate was 1:6, possibly due to the activation of chemical signals caused by mechanical

stretching and an effective intercellular communication distance. Therefore, the combination of cell

sheet engineering with the MEEK micrografting technique could provide high quality cells with a large

coverage area, which would be particularly beneficial in wound care applications.