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Simulated gastric leachate of 3D printer metal-fill filaments induces cytotoxic effects in rat and human intestinal models
Citation:
Hughes, M., H. Clapper, G. Tedla, T. Sowers, AND K. Rogers. Simulated gastric leachate of 3D printer metal-fill filaments induces cytotoxic effects in rat and human intestinal models. TOXICOLOGY IN VITRO. Elsevier Science Ltd, New York, NY, 97:105805, (2024). https://doi.org/10.1016/j.tiv.2024.105805
Impact/Purpose:
Three-dimensional (3D) printing is becoming more commonplace today, particularly in schools and personal residences. The printer filament used in the printing process, can consist of plastic and various additives, including metals. The metal additives enhance the stability, thermal and mechanical properties and tensile strength of the 3D printed object. Jewelry and small toys have been noted to contain leachable metals that are potentially bioavailable. The objective of this study was to assess whether metals in 3D filaments are bioaccessible in simulated gastric fluid. In this case, extruded filaments containing either copper, bronze or steel as additives were incubated in cell culture media at pH 2 for 2 hr. The media was then adjusted to pH 7 and then incubated with rat and human intestinal cells. Media containing copper- and bronze-fill filament leachate were cytotoxic to the cells, whereas leachate from the steel-fill filament had no effect. We found that a copper chelator incubated with two cytotoxic leachates decreased the cytotoxicity. This suggested that copper ions were released from the copper- and bronze-fill filaments which resulted in cytotoxicity. Scanning electron microscope and X-ray absorption spectroscopy of the treated copper-fill filaments showed physical changes in the filaments. Given the increasing use of 3D printing processes, program or regional partners, and public local communities will likely find this study of interest.
Description:
Metals are used in 3-dimensional (3D) printer filaments in the manufacture of 3D printed objects. Exposure to the filaments, printed objects and emissions from printing may pose health risks from release of toxic metals. This study investigated the cytotoxicity of extruded 3D printer filament leachates in rat and human intestinal cells. Copper-, bronze-, and steel-fill extruded filaments were incubated in acidic media for 2 h. Leachates were adjusted to pH 7 and cells exposed for 4 or 24 h. Concentration- and time-dependent decreases in rat and human cell viability were observed using a colorimetric assay and confirmed by microscopy. Copper- and bronze-fill leachates were more cytotoxic than steel. Copper-fill leachates had the highest copper concentrations by ICP-MS. Exposure to CuSO4 resulted in concentration-dependent cytotoxicity in rat cells. The copper chelator bathocuproine disulphonate alleviated cytotoxicity of CuSO4 and copper-fill leachate, suggesting that copper ions have a role in the cytotoxicity. Hydrogen peroxide increased and glutathione decreased in rat cells exposed to copper-fill leachate, suggesting the formation of reactive oxygen species. Overall, our data indicate that metals released from the acidic exposure of print objects using metal-fill filaments, especially copper, are toxic to rat and human intestinal cells and additional studies are needed.
URLs/Downloads:
DOI: Simulated gastric leachate of 3D printer metal-fill filaments induces cytotoxic effects in rat and human intestinal models
https://pubmed.ncbi.nlm.nih.gov/38458500/