Investigation of influence factors of embedded droplet printing for generation of cancer cell spheroids with controllable size*

The cancer cell spheroids, as one of the mostly utilized 3D in vitro model in laboratory, can provide a highly predictive value for the pre-clinical drug research of anticancer therapies. Whereas it is difficult to achieve the precise control over cancer cell spheroids size and composition by conventional methods. Here, we utilized a droplet printing mode of extrusion-based bioprinting to generate cancer cell spheroids in collagen bath. Through altering the settings of droplet printing mode of extrusion-based bioprinting (extrusion time and needle size) and cancer cell concentrations, cancer cell spheroids with different growth profiles and final sizes were generated. Robust bioprinter settings investigation holds the potential to empower researchers with reproducible and reliable platforms for predicting cancer cell spheroids growth profile and final size, and further being applied to evaluate drug efficacy, elucidating molecular mechanisms, and stratifying patient-specific treatment regimens in biomedical fields.