Fig. 3

a A vascularized organ-on-a-chip model was utilized to analyze BC cell invasion and metastasis through a microvascular network. b A multi-organ-on-a-chip system was composed of a “primary site” and three “main sites of metastatic”. This microfluidic system was used to model lung cancer metastasis to distant organs, which provided an experimental platform to analyze cell-microenvironment interactions in organ-specific metastasis. c Schematic diagram of the 3D bioprinting technology for organ-on-a-chip models. d An extrusion-based bioprinting platform that interrogates the paracrine loop between BC cells and macrophages in different geometric arrangement. An extrusion-based 3D bioprinting technique for constructing breast cancer metastasis model. e Fabrication of the 3D HeLa/hydrogel spheroids by 3D printing