Scratch wound assays are commonly performed to assess cellular migration and cell proliferation, often in response to therapeutic drug application. Wounding assays are also used to further understand the molecular phenomena related to wound healing, which includes cell signaling, immune and healing response to bacterial and fungal infections, and tissue remodeling. Most wounding assays are performed using a mechanical means to generate a break in a confluent monolayer of cells. Often this involves drawing a pipet tip or a pin over the monolayer. This physically damages the monolayer as desired, but also damages the cells, causing contents to leak and potentially complicating the interpretation of data. The other drawback of this method is that wound size and shape is highly variable contributing to difficultly in data analysis and inability to directly compare experimental conditions.
In this study we used the BioFlux 200 System (Figure 1) to wound cells enzymatically with trypsin, which eliminates cell damage at the wound edge. The microfluidic channels in the BioFlux plate are identical within <5%, conferring the ability to generate wounds by fluid flow that are highly regular in shape and similar in size. We studied both migration and proliferation following wounding by microscopy using a promoter of cell migration, epidermal growth factor, and a motility and cell cycle inhibitor, cytochlasin D.