MXene Bioinks for 3D Bioprinting: Design and Translation.

MXenes have emerged as electrically conductive, hydrophilic two-dimensional nanomaterials uniquely suited for electroactive bioink development. However, the field lacks an integrated design framework that links MXene surface chemistry and colloidal behavior to printability, electrical percolation, and tissue-specific biological outcomes. This review establishes a structure rheology biofunction paradigm for MXene-based bioinks, critically examining how synthesis routes, surface terminations, and oxidation dynamics influence shear-thinning behavior, network formation, and cytocompatibility. We analyze mechanistic pathways underlying cell-material interactions, including electrically mediated signaling and mechanotransduction in three-dimensional constructs. Emerging in vivo studies are evaluated with emphasis on biodistribution, immune modulation, and long-term biodegradation. Finally, we define key translational bottlenecks, oxidative instability, reproducibility, sterilization sensitivity, and regulatory classification, and propose actionable design criteria to advance MXene bioinks from laboratory constructs to clinically viable electroactive scaffolds.