Tailoring MXene Flake Morphology via Aerosol Jet Printing for Biological and Strain Sensor Applications

MXenes (Ti₃C₂T_x) are two-dimensional (2D) layered nanomaterials typically processed as aligned flakes. However, their morphology can also be engineered into crumpled architectures with distinct physicochemical properties that remain largely unexplored. Here, Aerosol Jet Printing (AJP) is established as a scalable manufacturing strategy to tailor MXene flake morphology through precise control of the printing conditions. By repurposing the printer's built-in alignment camera, a rapid monitoring method was developed to distinguish aligned and crumpled morphologies during fabrication. Systematic investigation of the printing parameters identified mass flow, nozzle size, and ink concentration as the key variables governing flake morphology, demonstrating its general applicability on other 2D materials, such as graphene and MoS₂. Aligned MXene films achieved electrical conductivities of up to 2672 ± 125 S cm^{- 1}, whereas crumpled films exhibited increased roughness and hydrophilicity. The engineered morphologies were further validated across multiple applications, including neural interfaces, antimicrobial coatings, and strain sensors. Both morphologies supported excellent biocompatibility with primary neurons and human induced pluripotent stem cell-derived neural cells, while crumpled MXenes enhanced antibacterial activity against Staphylococcus aureus and improved strain-sensing performance. These findings highlight the importance of controlling the morphology of 2D materials during 3D printing, providing a scalable route toward multifunctional biomedical devices.