Characterization of Copper‐ and Bronze‐Filled PLA: Mechanical, Structural, and Biological Insights for Biomedical 3D and 4D Printing

ABSTRACT Material extrusion (MEX), particularly Fused Filament Fabrication (FFF), is a widely used 3D printing technology, with growing interest in composite materials due to their broad range of applications. This study focuses on commercially available copper‐ and bronze‐filled polylactic‐acid (PLA) composites printed with FFF technology and on providing guidance for future practical applications, particularly in the biomedical field and 4D printing. In this research, static and dynamic mechanical tests, scanning electron microscopic imaging, and electric resistance measurements were conducted, and the thermal properties were determined by thermal conductivity measurements and differential scanning calorimetry, and thermogravimetric analysis (DSC‐TGA). Cytotoxicity was assessed using an A549 cell viability assay. The results show that the material's brittleness increases in proportion to the volume percentage of metal particles; among the copper composites FormFutura MetalFil – Classic copper (29.14 vol.%) had the lower tensile strength (15.4 MPa ± 0.17 MPa), while for bronze composites, the tensile strength was lower for ColorFabb BronzeFill (33.64 vol.%, 17.7 MPa ± 0.54 MPa). Furthermore, these composites have no cytotoxic effect in short‐term contact, and their enhanced thermal conductivity over traditional prosthetic materials makes them promising candidates for the development of prostheses intended to mitigate thermal discomfort.