Evaluating Particle Emissions and Toxicity of 3D Pen Printed Filaments with Metal Nanoparticles As Additives: In Vitro and in Silico Discriminant Function Analysis

The emergence of low-cost 3D printing (particularly with 3D pens) in the home and school environment is a matter of concern since there is a lack of data confirming its safe application. The filament washed with water and the particle emission during printing (captured in water) were analyzed. In this report, we provide important insights about toxicity, intracellular mitochondrial stress, and cellular metabolic alterations as a mechanistic response after exposure of emissions released during 3D pen printing with polylactic acid (PLA) and PLA filaments with additives (carbon nanotubes (CNTs), copper, or steel). We adopted the design and exposure of a realistic inhalation procedure of aerosols via introducing mist-containing particles released during 3D pen printing processes of filaments with/without additive (CNTs, steel, copper) to A549 cells in a cloud chamber. The filaments with or without additives appear benign except for copper, which causes higher changes in stress, cell death, and metabolic perturbations. Albeit live/dead cell assay fluorescence-activated cell sorting analysis revealed little or no toxicity, time-of-flight secondary ion mass spectrometry bimolecular imaging and chemical mapping show insightful changes in cell membrane lipid compositions. Biochemical profiles obtained based on ion m/z signature peaks exhibit membrane and lipoprotein metabolism alterations which are similar to those adopted by A549 cells while developing drug resistance and their activation of the expression of their efflux pump. The results sought in this report suggest the cautious use of 3D pen printers for filaments embedded with redox active metals as additives in a home environment.