Current developments in cell culture technology.

The ideal features of a cell culture system for in vitro investigation depend on what questions the system is to address. However, in general, highly valuable systems will replicate the characteristics and more specifically, the responses, of normal human tissues. Systems that can faithfully replicate different tissue types provide tremendous potential value for in vitro research and have been the subject of much research effort in this area over many years. Furthermore, a range of such systems that could mimic key genetic variations or diseases would have special value for toxicology and drug discovery. In the pursuit of such model systems, there are a number of significant practical issues to consider for their application, which includes ability to deliver with ease, the required quantities of cells at the time needed. In addition any cell culture assay will need to be robust and reliable and provide readily interpreted and quantified endpoints. Other general criteria for cell culture systems include scalability to provide the very large cell numbers that may be required for high throughput systems, with a high degree of reliability and reproducibility. The amenability of the cell culture for down-scaling may also be important, to permit the use of very small test samples (e.g., in 96-well arrays), even down to the level of single cell analysis. This chapter explores the range of new cell culture systems for scaling up cell cultures that will be needed for high throughput toxicology and drug discovery assays. It also reviews the increasing range of novel systems that enable high content analysis from small cell numbers or even single cells. The hopes and challenges for the use of human stem cell lines are also investigated in comparison with the range of eukaryotic cells types currently in use in toxicology.