Three Dimensional (3D) Cell Culture versus Two Dimensional (2D) Cell Culture
Its well known for over thirty years that cells grown using a 3D cell culture technique more closely mimic natural tissues and organs than cells grown in 2D. In 2D cell culture, cells are grown on flat dishes made of polystyrene plastic that is very stiff and unnatural. The cells adhere and spread on this plastic surface and form unnatural cell attachments to proteins that are deposited and denatured on this synthetic surface.
In 3D cell culture, cells attach to one another and form natural cell-to-cell attachments. The cells and the extracellular matrix that they synthesize and secrete in three dimensions is the natural material to which cells are attached. It is flexible and pliable like natural tissues. It is made of complex proteins in their native configuration and so provides important biological instructions to the cells. In this 3D cell culture environment, cells can exert forces on one another and can move and migrate as they do in vivo. These cell-to-cell interactions in three dimensional cell culture also include gap junctions which directly couple one cell to another.
These gap junctions are much more prevalent in 3D cell culture than 2D and these junctions enable cells to communicate with each other via exchange of ions, small molecules and even electrical currents. The close proximity of cells in 3D also enable surface adhesion molecules and surface receptors on one cell to bind to surface adhesion molecules and surface receptors on an adjacent cell. This coupling in 3D also maximizes cell-to-cell communication and signaling that is critical for cell function. Not too surprising, the phenotype or function of cells grown in 3D is more complex and closer to the functions of native tissues than cells grown in 2D. Liver cells will perform more liver cell functions in 3D versus 2D. Muscle cells will perform more muscle cell functions in three dimensional cell culture versus two dimensional cell culture. Cartilage cells will form more differentiated cartilage tissue in 3D versus 2D. And the list continues with nearly all the cells of solid organs and tissues.
The benefits of 3D cell culture over 2D cell culture also manifest when mimicking pathological conditions such as cancer. For example, breast cancer cells grown in 2D can easily be killed by low doses of chemotherapeutic drugs or low doses of radiation. If those same cells are grown in 3D, they are resistant to the same doses of chemotherapeutic drugs or radiation, just like cancer as its found in the body. In this way, cells grown in 3D are more valid targets for testing and discovering new drugs to treat cancer. Another benefit of testing drugs in three dimensional cell culture versus two dimensional cell culture is that cells in 3D form multi-layers of cells whereas cells grown in 2D form a monolayer of cells that is spread very thin on a plastic surface. When testing a drug in 2D, it needs only to diffuse a short distance across the cell membrane to reach its intended target. In 3D, the situation is more realistic and a drug needs to diffuse across multi-layers of cells to reach the cells on the inside of a microtissue.
The diffusion across multi-layers of cells more closely mimics the challenges found in the human body or in cancer where a drug needs to diffuse through multiple layers of cells before it reaches its intended target. Moreover, cells grown in 3D will form natural barriers to drugs such as tight junctions that bind cells tightly together and block or slow the diffusion of drugs, again making for a more realistic test.
3D Cell Culture is still a relatively new field so we understand you may have questions about 3d cell culture versus 2D cell culture, please don't hesitate to send us an email.
Contact a member of microtissues today for current 3D Cell Culture trends or advice at info at microtissues.com