Methods for advanced hepatocyte cell culture in microwells utilizing air bubbles

Flat, two-dimensional (2D) cell culture substrates are simple to use but offer little control over cell morphologies and behavior. In this article, we present a number of novel and unique methods for advanced cell culture in microwells utilizing air bubbles as a way to seed cells in order to provide substantial control over cellular microenvironments and organization to achieve specific cell-based applications. These cell culture methods enable controlled formation of stable air bubbles in the microwells that spontaneously formed when polar solvents such as cell culture media are loaded. The presence of air bubbles (air bubble masking) enables highly controllable cell patterning and organization of seeded cells as well as cell co-culture in microwells. In addition, these cell culture methods are simple to use and implement, yet versatile, and have the potential to provide a wide range of microenvironments to improve in vivo-like behavior for a number of cell types and applications. The air bubble masking technique can also be used to produce a micron thick layer of collagen film suspended on top of the microwells. These collagen film enclosed microwells could provide an easy way for high throughput drug screening and cytotoxicity assays as different drug compounds could be pre-loaded and dried in selected microwells and then released during cell culture.