Animal studies are widely used in pharma and in scientific research to investigate complex biological phenomena that can’t be studied with a simple two-dimensional (2D) cell culture. Individual animal models differ widely, especially when applied to human patients. To improve the validity of such experiments, innovative models are therefore needed to obtain more accurate findings.
In many cases, animal testing is not even necessary, and there are very convincing alternatives - especially three-dimensional (3D) cell culture. In this article, we explain why 3D cell culture is an excellent alternative to animal models.
There are many reasons to move from animal-based to 3D cell culture models, but regardless of the quality of the model, one of the biggest disadvantages of animal models are ethical concerns.
In 1959, Russel and Burch therefore defined the 3Rs principles for the use of animals in research: replacement, reduction, and refinement – to provide better treatment for experimental animals. Whenever possible, replacement should come first. If replacement is not yet feasible, the goal is reduction and refinement. The term "reduce" means to minimize the number of animals used, and "refine" refers to the use of techniques that cause less harm to animals. The importance of finding alternatives to animal testing is also reflected in the increasing pressure from legislators to reduce the use of animal models.
Animal testing is often lengthy and very expensive because maintaining and operating an animal facility requires many resources. Animal-free methods are much cheaper and less time-consuming. Therefore, when setting up a new laboratory, it makes sense to thoroughly investigate whether and how animal testing can be avoided.
3D models can use human cells and therefore better reflect human physiology. Many animal models are simply too far removed from human physiology to accurately represent what is going on, therefore transfer of in vitro results to humans can be questionable. [1]
Cell culture allows much better control of variables of interest. With animal experiments, on the other hand, the complexity of the organisms means that reproducibility is not always guaranteed. Therefore, cell culture can improve reproducibility and facilitate the study of cellular and molecular mechanisms. Validation of 3D cultures can be done, for example, with mass spectrometry-based proteomics.
Things are also getting easier when it comes to workflows: Technologies like magnetic 3D cell cultures (M3D) make it convenient for scientists to carry out the practical steps of growing and handling cells. They enable, for example, the ability to quickly change media without interfering with the physiology of cells. The valuable time saved in changing media means that contamination and cell death are reduced, as they are directly related to cultivation time.
Cells can be aggregated with magnetic forces, either by levitation or bioprinting, to form structurally and biologically representative 3D models in vitro. The advantages of M3D cell culture include:
With M3D cell culture solution addition and removal are made easy by using magnetic force to hold them in a stationary position during aspiration, thereby limiting spheroid loss. Spheroids can also be picked up and transferred between vessels using magnetic tools such as the Multi-MagPen.
NanoShuttle-PL particles consist of iron oxide, poly-L-lysine, and gold. NanoShuttle-PL magnetizes cells by electrostatically attaching to cell membranes during an overnight static incubation. Magnetized cells will appear peppered with dark nanoparticles after incubation. NanoShuttle-PL will stay attached to the cell membrane for up to 8 days, at which point it’s released into the 3D culture. NanoShuttle-PL is biocompatible, having no effect on metabolism, proliferation, and inflammatory stress, and even encouraging proliferation in 3D . Additionally, it does not interfere with experimental techniques, such as fluorescence, or Western blotting.
Since human-based models can be grown with human cells, they enable the development of personalized medicine. Autologous cells can be grown for drug testing and disease modeling and can even be useful for assessing diagnoses. Tissue engineering can provide autologous tissue for patients in need of grafts for surgical reconstruction. Because of the high risk of immunological rejection and public health concerns, animal tissue transplantation is very limited in humans. Cell culture overcomes many of the limitations in transplantation, such as the lack of healthy tissue from a donor site, by allowing the growth of autologous and physiologically relevant tissue for grafts. [1]
When you choose Greiner Bio-One , you benefit from decades of expertise and consistent excellence. Greiner Bio-One are leaders and innovators in 3D cell culture technology and are always here for you - with better products, dedicated support, and better materials such as protocols and application notes to help you succeed.
The 3D cell culture market is growing every year and is expected to reach 1846 million USD in 2024 [2]. Every year the techniques are improved; scientists can now produce skin, cornea, blood vessels and much more with 3D cell cultures. There are certainly improvements to be made to completely replace animal testing with 3D cell cultures, but we are well on our way.
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[1] Bédard P, Gauvin S, Ferland K, Caneparo C, Pellerin È, Chabaud S, Bolduc S. Innovative Human Three-Dimensional Tissue-Engineered Models as an Alternative to Animal Testing. Bioengineering (Basel). 2020 Sep 17;7(3):115. http://doi.org/10.3390/bioengineering7030115. PMID: 32957528; PMCID: PMC7552665.
[2] Huh D, Hamilton GA, Ingber DE. From 3D cell culture to organs-on-chips. Trends Cell Biol. 2011 Dec;21(12):745-54. http://doi.org/10.1016/j.tcb.2011.09.005. Epub 2011 Oct 25. PMID: 22033488; PMCID: PMC4386065.