Systematic standardization of organ-on-a-chip under controlled flow conditions: use case with Caki-1 and A549 cell lines

New in vitro models are an urgent need for to improve both the research data and the preclinical development of new drugs. Current standardized cellular models are mainly based in 2D cell culture, which lacks flow conditions and with complex co-culture settings. In this way, advanced cell culture models, such as organ-on-a-chip (OoC), aim to solve these limitations. OoC systems are composed by a microfluidic chip functionalized with different combinations of extracellular matrixes, coatings and cell cultures to mimic the physiological conditions of human organs. Advantages of OoC include the possibility to add 3D structures, delimited regions for co-culture and dynamic flow conditions to cell cultures. However, to perform reproducible and controlled experiments with OoC, it is necessary to systematically standardize the cell culture conditions in the microfluidic channels. For this is necessary to test both the combination of flow and extracellular matrix (ECM) coating to reliably mimic the human organ physiology. In this work, we standardized both conditions, ECM coating and the flow conditions to functionalize OoC with cell lines from kidney (Caki-1) and from lung (A549) to develop OoC systems beyond the Vessel-on-a-chip setting. In this way, the protocol detailed in this work will allow to standardize cell culture on different optimized OoC types with different cell types from different origins.