Flow cytometry as an analytical method of drug-induced apoptosis in 3D bioprinted melanoma cells.

Three-dimensional (3D) cell culture systems have gained increasing interest in drug discovery and tissue engineering due to its inherent advantages in providing more physiologically relevant information and more predictive data fortests. Along with the development of more physiologically relevant 3D cell culture models, researchers bear the responsibility to validate new cell assay techniques capable of measuring and evaluating constructs that are physically larger and more complex compared to two-dimensional cell cultures. It is important to note that assays based on monolayer cultures may be insufficient for the use in 3D cell cultures models. In this study we firstly fabricated a 3D bioprinted hydrogel melanoma scaffold. This was used to validate a flow cytometry-based analytical method as a tool for 3D bioprinted structures to assess drug-induced apoptosis. The results indicated high robustness, reproducibility and sensitivity of the flow cytometric method established on the 3D cell-laden A375 melanoma hydrogel scaffolds. Over and above this, it was possible to determine the effect of etoposide on A375 melanoma cells using Annexin V and propidium iodide apoptosis assay.