Proliferation and Fiber Formation of Human Dermal Fibroblasts on Patterned Differentially Adherent Substrates

Fibroblast cells are crucial in the human body for maintenance of the extracellular matrix, including synthesizing macromolecules like collagen, and they play a critical role in wound healing of soft tissues such as skin [1]. Directing fibroblast growth is an important step in tissue engineering where the focus has gone from a top-down approach of homogeneously introducing cells into a pre-formed scaffold to a bottom-up approach in which the tissue construct is built on a cell-by-cell basis with ability to manipulate specific cell environments through location, proximity, and geometry. The ability to direct cell proliferation to encourage organized tissue formation can provide tissue engineers a means of controlling the architectural and mechanical properties of soft tissue scaffolds. This approach to functional tissue engineering represents a novel direction for the development of replacement tissues. Previous attempts of directed growth have proven successful with C2C12 mouse myoblast cells. Using laser micromachined channels in agarose hydrogel lined with a basement membrane matrix, myoblast cells were guided to align and produce myotubes [2]. The objective of the current study was to apply similar principals to direct fibroblast cell growth and proliferation, ultimately leading to their growth into three-dimensional fibers, on differentially adherent substrates. Channels (widths ranging from 60 μm to 200 μm) were laser micromachined in agarose gel to explore an optimal geometry for cellular proliferation and fiber formation. The fibroblast cells used range in size from roughly 20–30 μm. Thus, the width of each channel was chosen to explore which multiple of cell width would allow for directional alignment parallel to the channel and subsequent fiber growth. The ability to direct fibroblast cells to align and produce fibers through manipulation of their environment is critical to our laboratory’s ongoing efforts to develop three-dimensional customized tissue replacement constructs to be used in many soft tissue applications such as ligament and skin grafts.