Ultrashort-Pulse Laser Material Processing

During material processing with ultrashort-pulse lasers, fine dust is generated. Within the framework of the Fume research project (AiF), particle emissions from various materials and processing parameters were systematically investigated and assessed toxicologically.

The emitted particles mostly exhibited bimodal size distributions below 100 nm, i.e., in the ultrafine dust range. For the toxicological assessment, an in-vitro approach using human lung cells in Air-Liquid-Interface (ALI) culture was employed. The sample material collected on a filter was transferred into an artificial fluid that mimics the liquid layer in the lung and then applied in direct contact to the cell cultures to simulate the real conditions at the inner lung surface.

To evaluate cellular effects, measurements were taken of mitochondrial membrane potential (MMP), general cell stress markers, and after 72 hours, the release of interleukin-8 (IL-8), which plays a role in inflammatory processes. All measurements were conducted with the materials CuO, kaolin, stainless steel, aluminum, aluminum oxide, silicon, polypropylene (PP), polystyrene (PS), and polyethylene (PE) across a dose range of 3-100 µg/cm² of cell culture surface. Dose-response curves for cell viability were used to determine median effective doses (ED50) and no-effect-level (NOEL) values.

Within the investigated dose range, no indications of acute toxic effects of the particles on lung cells were observed.