The development of three-dimensional (3D) culture cell assay systems has improved the field of cell-based research. The complexity and the relevance of tissue in-vivo cannot be accurately represented by traditional monolayer cultures. Whereas, 3D and organotypic culture systems seek to mimic the three-dimensional architecture and cellular interactions found in organs and tissues. These systems are based on culturing cells in matrices or scaffolds that offer structural support and enable interactions among cells and matrix. Certain cell-types cannot maintain their differentiation state unless they are cultured in 3D-organotypic conditions. The spatial organization allows 3D and organotypic cultures to enable better replication of native tissue structures and functions.
3D cell culture system applications offer a better understanding on cell behavior, cell signaling, compound effects, and disease modeling. Additionally, they have also enhanced the knowledge regarding tissue development, regeneration, and the effects of various compounds on complex biological systems. The development of 3D and organotypic culture cell assay system is widely used in protocols on preclinical research, drug discovery, and personalized medicine approaches. Examples as such is the development of three-dimensional matrices of polymerized collagen, including fibronectin or collagen type-I, enhances our understanding regarding the evaluation of proliferative response as well as the signaling pathways involved by using specific kinase inhibitors. Additionally, 3D organotypic cultures improved the evaluation of Intervertebral disc (IVD) cell responses to mitogenic growth factors, where Annulus fibrosus (AF) cells are cultured in collagen type-I gels, while nucleus pulposus (NP) cells are cultured in chondroitin sulfate A (CSA) supplemented collagen gels, and the effects of Platelet-Derived Growth Factor (PDGF), basic Fibroblast Growth Factor (bFGF), and Insulin-Like Growth Factor-I (IGF-I) were examined. These advanced culture models have great potential to significantly improve therapeutic interventions and treatments.