Large Population Of Homogeneous Spheroids Models For Testing Toxicity And Diffusion Of Nanomaterials

The toxicity and the therapeutic effect of drugs need to be assessed on relevant cell models before they are tested on animal models or humans. Analogously, the safety of nanomaterials intended to be used in food should be tested for toxicity on relevant and reliable models. In recent years, the use of 3D cell models has been recognized as a step forward in complexity and relevance in biological cell assays. These models can mimic the complexity and the biological barriers of tissues better than conventional 2D systems. Nowadays, protocols are available to produce 3D cell models for many cell types. One of the common problems in 3D cell models is the variability in shape and size of the 3D structures, leading to a scarce reliability of the assays. We have developed and improved methods for the culturing of 3D spheroids in microwells arrays that could also mimic the mechanical properties of tissues. Large populations of up to several hundreds of homogeneous 3D tumor spheroids can be produced reliably and their growth and molecular properties can be characterized in situ during and after growth or treatment with drugs or nanostructures. It is possible to characterize the drug distribution in the spheroids in order to gain insight into their penetration properties and persistence. Recently, we obtained 3D heterotypic cell spheroids where 3D cell structures are made of different cell types so that more complex and reliable tissue models can be obtained. Additionally, it is possible to exploit the 3D bioprinting technology to obtain complex cell mixtures and achieve 3D heterotypic cell models with a range of compositions and treat them with drugs or nanostructures in the same environment. We trust that this technology will prove useful in reliably and quantitatively testing the toxicity and other biological effects of food-relevant nanomaterials as well as other nanostructures.