3D Cell Printing and Manipulation with Magnetic Bioinks

Three-dimensional (3D) cell culture models more faithfully reproduce native tissue organization and function than conventional two-dimensional systems, yet many existing bioprinting methods depend on scaffolds, complex instrumentation, or limited control over cell positioning. This review examines magnetic bioinks as a versatile platform for contactless 3D cell manipulation and biofabrication. It first outlines the fundamentals of magnetophoresis and defines magnetic bioinks as combinations of magnetic agents, including magnetic nanoparticles or paramagnetic salts, with biological components such as cells, proteins, or fluids. The review then compares label-based strategies, in which cells are magnetized and guided by positive magnetophoresis, with label-free approaches that exploit magnetic susceptibility differences to position diamagnetic cells through negative magnetophoresis. Across these methods, magnetic bioinks have enabled single-cell sorting, spatial patterning, spheroid and co-culture assembly, multilayer tissue formation, and hydrogel-integrated printing. These capabilities support applications in disease modeling, drug screening, biosensing, regenerative medicine, and emerging biofabrication under microgravity conditions. The paper also highlights key limitations, including nanoparticle biocompatibility, paramagnetic salt toxicity, osmotic stress, and the need for better assay standardization and translational validation. Overall, magnetic bioinks represent a promising scaffold-free approach for rapidly producing physiologically relevant 3D biological constructs for research and clinical innovation.