High-ThroughputProgrammable Tumor Spheroid GenerationUsing the Magneto-Archimedes Effect

Three-dimensional (3D) tumor spheroids in vitro have great potential in drug discovery and tissue engineering due to their similarity to real tissues. Herein, we develop a simple strategy, with time and cost-effective, noninvasive characters to produce high-throughput 3D tissue spheroids using the magneto-Archimedes effect. This method is versatile in producing various morphologies of tumor spheroids by using different templates, as well as spatially coded tumor spheroids by adding different cells in the defined orders. The prepared tumor spheroids are similar to the mouse homograft tumors, as confirmed by immunofluorescence experimental results. We demonstrate that the prepared tumor spheroids can be used for anticancer drug screening, tumor inoculations, and the study of chemical signal transduction between artificial cell aggregates and tumor tissues. Temozolomide (TMZ) is found to be more effective than 5-FU toward gliomas. Further, C6 tumor spheroids are successfully inoculated into mice to grow tumors with a rapid growth rate than free cells. In the hybrid structure containing artificial cell aggregates and tumor spheroids, reactive oxygen species (H₂O₂) are generated in the artificial cell aggregates, which diffuse into tumor spheroids to cause the redistribution of intracellular Ca²⁺ in tumor cells, consequently inducing cell apoptosis. This method is easy to scale up by using large magnets. It provides great potential in complicated tissue structure construction, antitumor drug screening, and tissue engineering.