Animals in research Animal replacement Cell Culture Cell culture is the term given to the method by which cells are grown outside of their natural environment in a laboratory setting. Cell culture is not a new technique. The first paper which described the modern usage and techniques of cell culture was published in 1907. Cells can be isolated from tissues for ex vivo culture in several ways. Two of the most common include releasing cells from soft tissues by enzymatic digestion, and directly placing sections of tissue in growth media, the resulting cell proliferation can then be used to seed further culture. Cells that are cultured directly from a subject are known as primary cell cultures. With a few exceptions, most primary cell cultures have a limited lifespan. The cells stop dividing and lose viability which is why researchers are always looking to obtain fresh tissue/cells for their research. Cells grown in this way usually form a flat sheet of cells (monolayer) on the plastic support on which the cells are placed. This type of cell culture, where the cells grow to form a flat sheet, is known as 2D (2-dimensional) cell culture. Modern techniques now allow cells to adopt a more ‘natural’ 3D shape and these new cultures are known as 3D cell culture. 3D cell culture techniques allow cells to survive in a more natural environment similar to the physiological conditions that there would be in a human tissue. Another advancement on traditional culture is the co-culture system. This is mainly done in 3D systems and is where more than one cell type are grown together. Most human tissue contains more than one cell type and so these modern 3D co-culture systems are much closer to the human body than ever before. Managing cells Cells require a lot of help and support to keep them alive and functioning as close as they would in an in vivo situation. Cells are kept and worked with under sterile conditions to avoid microbial contamination or contamination with other cell lines. Use of cell culture Cell culture systems have many applications. Primarily, cell culture is used to understand the fundamental changes that occur to cells and tissues in disease states. Additionally, these same systems can be used to determine whether the cells or tissues under investigation respond to drugs or other treatments. Cell culture is also useful in producing drugs, vaccines or other biological materials useful in human medicine and scientific research. Cell culture as an alternative to animal experiments Cell culture is a popular alternative to animal experiments as the cells under study can be closely observed and the environment monitored in order to be able to get the most useful and human-relevant data possible although they do have their own set of limitations. For many years scientists have been developing both 2D and 3D cellular models of various diseases. Animal Free Research UK in particular has been at the forefront of this research, with some of our first cell culture projects being funded in the early 1980s. Animal Free Research UK funded its first 3D cell culture project in 2004 which looked at developing the first ever 3D model of breast cancer. Cell culture has come a long way from its humble beginning and is now seen as one of the primary ways in which to develop an alternative to animal experiments and alleviate the suffering experienced by hundreds of thousands of animals every year.