This is a guest post from the BiotechBlog Intern, Fintan Burke. Fintan is a student at the School of Biotechnology at Dublin City University. Do you have a response to Fintan’s post? Respond in the comments section below.
As researchers continue to investigate the complex nature of cell tissues and their behaviour, it is becoming increasingly apparent that conventional tissue culture methods such as Petri dishes and well plates are only capable of giving a fraction of the picture.
Over the last few years, there has been increased interest in novel approaches that allow cell cultures to grow in a 3D media. Indeed, 3D culture boasts many benefits over conventional 2D media. In a 2007 Nature article, Pampaloni et al argue that 3D culture has the potential to represent a true in vivo cellular environment without the need of ethically questionable animal testing. This type of culture can also give better insight into cell architecture, signalling and mechanics, which has already been recognised in cancer research; a 2008 study by Fischbach et al showed that tumor cells grown in 3D culture “recreated tumor microenvironmental cues” as well as increased tumor vascularisation compared to that of 2D cell cultures.
Demand for 3D culture is expected to grow as researchers search for new approaches to cellular research while lessening the need for animal testing. From this demand, several approaches have been taken to develop 3D culture methods:
One method involves offsetting the natural sedimentation of cells in an aqueous media by gently rotating the bioreactor in an apparatus called a rotating wall vessel bioreactor. Cells will typically be attached to microcarrier bead “scaffolds” to allow for 3D chemical responses in the bioreactor. Originally developed by NASA to examine microbial growth in zero gravity, the culture method boasts the advantage of replicating the natural low shear effect found in the body which has been found to be influential in a pathogen’s infection potential.
Another system employs magnetism to develop 3D tissue cultures. This method, termed magnetic cell levitation, uses loaded bacteriophages to “infect” the cells for culture with faint amounts of iron oxide and gold. These cells are then left in a Petri dish to grow while a ring placed on top of the dish subjects them to magnetic forces, causing them to hover in suspension. In a 2010 issue of Nature Nanotechnology, Souza et al argue that this method has the potential to “be more feasible for long-term multicellular studies” as well as its ease of control and cost-effectiveness in research.
Recently attention has been paid to developing 3D culture media without an external influence. Microtissues Inc. has developed a form of tissue culture that rids the need of scaffolds in the culture. The result, claims CEO Jeffrey Morgan, is that uniform cells are prepared more efficiently and with more constant results than when scaffolds are used. Another company, Microtissues.com, also claim their 3D Petri dish maximises cell-cell interactions and allows controllable cell size.
These examples represent only a fraction of the new methods being constantly developed for 3D culturing of cells. As recently as last month, TAP Biosystems unveiled their newest collagen-based 3D cell culturing method for 96-well plates. This recent boom in development is undoubtedly due to the realisation that research using the (since now) conventional 2D culture is nearing its end. Though 3D culture has the potential to become the fundamental choice for research into cancer and drug therapy, some issues remain. Modern microscopic imaging may struggle with the denser tissue samples. A common standard also needs to emerge in order to establish a unified protocol in research. Should these concerns be addressed, there can be little doubt that 3D cell culture will emerge as the cheap, informative and dominant research method for years to come.