Characterization of microcircular wounds pressurized by a hybrid chip-on-dish method for live cell adhesion and mobility testing

Most wound generation tools have a limitation of generating circular wounds on live cells cultured in a Petri dish, since those wounds have been mostly formed by placing a circle-shaped sticker on the target area before cell culture. It does not mean an actual circular wound with cell debris, but a cell empty space from the initial stage of cell culture. Here, we report a new method of generating microscale circular wounds in a controlled manner at the benchtop affordable level. We also analyzed how those wounds were radially closed according to two stress components, such as 'stretched' and 'compressed' sides. To demonstrate our proof-of-concept validation, we designed and fabricated a hybrid poly(dimethylsiloxane) (PDMS)-dish device with a connected array of circular microstructures. We performed pressure analysis by using two different types of cells, such as the HeLa cell line and primary total finger cartilage (TFC) chondrocytes, as models. We measured and analyzed the wound closure status, such as the cell recovery direction and time, at the cellular level by differential interference contrast (DIC) and fluorescence microscopy. The results showed that TFC cells required larger mechanical pressure than HeLa cells for wound generation. This may imply that the shape and size of the wounds would depend on the amount of the extracellular matrix and the presence or absence of the cell adhesion protein. It was confirmed that the direction of cell migration was changed depending on the degree of confluence and the starting point of cells on the rim of the circular wounds. This approach can be useful as a new assay for studying fundamentals of radial cell migration dynamics for circular wound closure of different types of cells.