Volatile Organic Compound Emissions from Resin-Bed 3D Printers and Toxicological Effects in Cultured Human Lung Cells

Three-dimensional (3D) printing is a fast-growing technique becoming increasingly popular amongst professionals, businesses and hobbyists. However, exposure from volatile organic compounds (VOCs) emitted from them has not been well documented, nor potential health implications following exposure. This thesis aims to identify VOCs emitted from desktop resin-based 3D printers through a variety of scenarios and investigate the toxicological impact of their emission on human lung epithelial cells.

The methodology used were mixed methods studies. VOC analysis was carried out using thermal desorption coupled gas chromatography mass spectrometry within an exposure chamber and an experimental room to quantify the emission of VOCs as a function of time. Human lung epithelial cells (A549 cell lines) in a submerged monolayer culture were then exposed to the compounds identified, and analysed for changes in their morphology, survivability and protein expression using flow cytometry and liquid chromatography mass spectrometry. Finally, the habits of 3D printer operators were assessed using a questionnaire to understand their potential exposure, and whether they employ any safety measures.

The VOCs identified were mainly acrylic compounds, constituting the resin monomers that polymerise into the printed structure, with the highest quantified compounds in the exposure room being 2- and 3-hydroxypropyl methacrylate (44 and 33 μg/m3). Two mitigation methods were tested to assess the reduction in VOC concentration, distance from the 3D printer, and a HEPA filter extraction hood. Both methods significantly reduced VOC concentrations experienced by an operator in many of the VOCs identified. Human lung cells had no difference in morphology or survival after exposure, though exhibited altered protein expression surrounding multiple protein synthesis pathways. Dysregulation in these pathways has been previously linked to cancer and neurological disorders.

This thesis concludes that VOC exposure from resin 3D printers may have health risks which are non-negligible and should be explored further.