Autologous keratinocyte grafts provide clinical benefit by rapidly covering wounded areas, but they are fragile. We therefore developed biocompatible hexagonal-packed porous films with uniform, circular pore sizes to support human keratinocytes and fibroblasts. Cells were cultured on these porous poly (epsilon-calprolactone) films with pore sizes ranging from novel ultra-small 3 microm to 20 microm. These were compared with flat (pore-less) films. Cell growth rates, adhesion, migration, and ultrastructural morphology were examined. Human keratinocytes and fibroblasts attached to all films. Furthermore, small-pore (3-5 microm) films showed the highest levels of cell adhesion and survival and prevented migration into the pores and opposing film surface. Keratinocyte migration over small-pore film surface was inhibited. Keratinocytes optimally attached to 3-microm-pore films due to a combination of greater pore numbers (porosity), a greater circumference of the pore edge per unit surface area, and greater frequency of flat surface areas for attachment, allowing better cell-substrate and cell-cell attachment and growth. The 3-microm pore size allowed cell-cell communication, together with diffusion of soluble nutrients and factors from the culture medium or wound substrate. These characteristics are considered important in developing grafts for use in the treatment of human skin wounds.