Programing Cell Assembly via Ink-Free, Label-Free Magneto-Archimedes Based Strategy

Tissue engineering raised a high requirement to controlcell distributionin defined materials and structures. In ink-basedbioprintings, such as 3D printing and photolithography, cells wereassociated with inks for spatial orientation; the conditions suitablefor one ink are hard to apply on other inks, which increases the obstaclein their universalization. The Magneto-Archimedes effect based (Mag-Arch)strategy can modulate cell locomotion directly without impelling inks.In a paramagnetic medium, cells were repelled from high magnetic strengthzones due to their innate diamagnetism, which is independent of substrateproperties. However, Mag-Arch has not been developed into a powerfulbioprinting strategy as its precision, complexity, and throughputare limited by magnetic field distribution. By controlling the paramagneticreagent concentration in the medium and the gaps between magnets,which decide the cell repelling scope of magnets, we created simultaneouslymore than a hundred micrometer scale identical assemblies into designedpatterns (such as alphabets) with single/multiple cell types. Cellpatterning models for cell migration and immune cell adhesion studieswere conveniently created by Mag-Arch. As a proof of concept, we patterneda tumor/endothelial coculture model within a covered microfluidicchannel to mimic epithelial-mesenchymal transition (EMT) under shearstress in a cancer pathological environment, which gave a potentialsolution to pattern multiple cell types in a confined space withoutany premodification. Overall, our Mag-Arch patterning presents analternative strategy for the biofabrication and biohybrid assemblyof cells with biomaterials featured in controlled distribution andorganization, which can be broadly employed in tissue engineering,regenerative medicine, and cell biology research.

Automated summary

Tissue engineering requires precise control of cell distribution in materials and structures. Current ink-based bioprinting methods face challenges in achieving universal applicability due to the specific conditions required for different inks. The Magneto-Archimedes effect based strategy offers a promising alternative by directly modulating cell locomotion without relying on inks. However, its widespread adoption has been limited by the complexity and precision of magnetic field distribution. By controlling the paramagnetic reagent concentration and magnet gaps, researchers have successfully patterned micrometer-scale cell assemblies with single or multiple cell types. This Mag-Arch patterning technique has potential applications in tissue engineering, regenerative medicine, and cell biology research.