Bioprinting approaches are of great promise for tissue engineering applications as they allow the fabrication of constructs able to mimic native tissues’ mechanical and topographical features. Additional control over cells fate can be enhanced using stimuli-responsive materials, requiring the development of novel bioinks for this purpose. In this study, bioinks comprising κ-carrageenan, collagen, and magnetic nanoparticles were designed for 3D bioprinting applications. The characterization of this material was performed, where mechanical compressive tests yielded Young’s moduli ranging from 8.25 to 18.4 kPa. Rheological assessments also revealed the shear-thinning behavior of the bioinks and a temperature-dependent gelation. The capability of these bioinks to produce 3D constructs by extrusion bioprinting was established through the printability evaluation and the development of complex structures, supporting the viability and proliferation of mesenchymal stromal cells (MSCs). Finally, as proof-of-concept, it was observed that the secretome of bioprinted MSCs stimulated with an external magnetic field of 80 mT was able to increase the number of tubes formed by human umbilical vein endothelial cells.

Cancer cells possess distinct bioelectrical properties, yet therapies leveraging these characteristics remain underexplored. Herein, we introduce an innovative nanobioelectronic system combining a piezoelectric barium titanate nanoparticle core with a conducting poly(3,4-ethylenedioxythiophene) shell (BTO@PEDOT NPs), designed to modulate cancer cell bioelectricity through noninvasive, wireless stimulation. Our hypothesis is that acting as nanoantennas, BTO@PEDOT NPs convert mechanical inputs provided by ultrasound (US) into electrical signals, capable of interfering with the bioelectronic circuitry of two human breast cancer cell lines, MCF-7 and MDA-MB-231. Upon US stimulation, the viability of MCF-7 and MDA-MB-231 cells treated with 200 μg mL<sup>-1</sup> BTO@PEDOT NPs and US reduced significantly to 31% and 24%, respectively, while healthy human mammary fibroblasts (HMF) were unaffected by the treatment. Subsequent assays shed light on how this approach could interact with cell’s bioelectrical mechanisms, namely, by increasing intracellular reactive oxygen species (ROS) and calcium concentrations. Furthermore, this system was able to polarize cancer cell membranes, halting their cell cycle and potentially harnessing their tumorigenic characteristics. These findings underscore the crucial role of bioelectricity in cancer progression and highlight the potential of nanobioelectronic systems as an emerging and promising strategy for cancer intervention.