Fig. 3

Examples of breast cancer-on-chips. a Bifurcated chip to study a possible solution for the acidification of the primary tumor environment. (i) Design of the microfluidic device: the upper chambers are loaded with CaCO₃ nanoparticles able to neutralize the acidification of the TME. (ii) Chip setup. Pipette tips are used to feed the upper and lower chambers, while the middle channel (which ensures the separation between the control and experimental compartments) is connected to a syringe pump. Adapted from [144] with permissions from Scientific Reports. b Organ-on-chip model to analyze the tissue-specific breast cancer extravasation. (i) Schematic illustration of the extravasation chip with the Side 2 view highlighted. (ii) Z-stack projection images of Side 2 view showing HUVEC-C endothelial monolayers (green), extravasated (arrowhead), and associated (arrow) human breast cancer cells (MDA-MB-231, red) into the lung, liver, or breast microenvironments. Adapted from [145] with permissions from Biotechnology & Bioengineering. c Miniaturized bone-on-a-chip to study breast cancer bone metastasis. (i) Schematic of the simultaneous-growth-and-dialysis mechanism. Low-molecular-weight nutrients and metabolic waste move continuously through the dialysis membrane. While large bone matrix-building proteins accumulate in the bottom chamber contributing to the spontaneous formation of the osteoblastic tissue. (ii) Exploded view of the bone-on-a-chip. (iii) Injected inks highlight the central circular area of the assembled chip. Dialysis occurs in this space. Adapted from [146] with permissions from Small