Cell Culture 3D: A Leap Towards In Vivo
3D cell culture has been a boon to the scientific community for cell culture experiments and is extensively used as an alternative to in vivo animal experiments. 3D cell culture presents itself as an assembly of cells that mimics tissue-specific / organ-specific architecture.
2D cell culture is the most common cell culture practice in vitro for biochemical or biophysiological experiments. In 2D cell culture practice, a monolayer cell growth is formed over an adherent surface with growth media and supplements to aid survival. But this model is not sufficient to correctly assess or predict crucial cell signaling pathways and other processes that occur in the body. In living tissues inside the body, the cells are present in a 3D microenvironment where complex cell-cell and cell-matrix interactions prevail. Therefore, researchers have readily taken up the practice of 3D cell culture which bio-mimics the tissue environment and can closely predict the complex cellular interactions that help in delivering clinically viable therapeutics.
It promotes tissue organization using micro-assembled structures and a complex in-vivo-like environment. This technology also grants the possibility to grow simultaneously two different cell types with accurate co-cultures imitating cellular functions observed within a tissue as interactions between different types of cells are the key elements in body functions. Moreover, 3D cell culture makes it easier to control and monitor the parameters of temperature, chemical gradients, oxygen rate, pH, etc. as close to an in vivo reality as possible. These advantages have helped 3D cell culture technique to be regarded as one of the most significant discoveries of biomedical research in the areas of wound healing, drug metabolism, toxicity testing, microfluidics and bioimprinting.
3D cell culture methods can be classified broadly into scaffold-based techniques and scaffold-free techniques. Scaffolds can be convenient supports for 3D cell culture due to their porosity, and waste transportation ease. Cells can proliferate and eventually adhere on the surface of the scaffold to gain the shape of the tissue or organ to be transplanted after processing. The cells on the scaffold interact with each other and form a mimicking micro-environment on the structure. In order to avoid issues with immunity and weak growth, the scaffold used must support proper cell growth and be bio-compatible. Scaffolds can be gel-based or polymer-based made of synthetic or natural derived materials. On the other hand, scaffold-free techniques are used to generate spheroids i.e., cell aggregates serving as good physiological models. Cell spheroids formed using scaffold-free technique are mainly done using the forced-floating method, the hanging drop method or the agitation-based method.
But one must bear in mind that although 3D cell culture is a bridge between in vitro and in vivo research, it is a relatively new technique and has not been fully understood to be exploited limitlessly. Unfortunately, 3D culture technique presents some noticeable challenges like soluble interference factors in the culture or adherence limitations. Besides these, one of the most important future challenge in this technique is developing automation and reproducible applications in the clinical domain.
