Two-dimensional materials (2D materials) are a relatively new class of engineered nanomaterials (ENM) defined by their property of being one or two atoms thick, with atoms arranged in a two-dimensional plane. Since 2010, these materials have slowly but consistently progressed from lab bench discoveries to real-life products and have now reached the global market. While this transfer from academia to industry has been relatively fast, there remain some concerns as to their safety profiles, which have not been studied as extensively as their properties and applications [1]. Cell culture-based assays are currently the most accessible and sustainable methods to evaluate the potential of ENMs to cause harm to humans. They have been developed as alternatives to the costly and time-consuming animal-based assays that have been used for decades for safety testing of new chemicals and to allow testing all existing ENMs. While some of these assays have proven to be highly reliable to predict 2D material deleterious impacts (after confirmation of similar outcomes in animal models), some assays were revealed to be not applicable for hazard testing of these flat materials due to interference of the materials with reagents, causing misleading results.