On October 23 was published in the prestigious international journal Proceedings of the National Academy of Sciences (PNAS) the article entitled “Nearly free surface silanols are the critical molecular moieties that initiate the toxicity of silica particles” (https://doi.org/10.1073/pnas.2008006117). The study, the result of a research project involving the University of Turin and the Université catholique de Louvain and funded by the European industrial association Eurosil, has identified the chemical structures responsible for the molecular mechanisms that make crystalline silica toxic.
The authors of the Department of Chemistry of UniTO – Cristina Pavan, Francesco Turci, Bice Fubini, Maura Tomatis and Riccardo Leinardi, of the Interdepartmental Center “G. Scansetti”, in collaboration with Gianmario Martra, Rosangela Santalucia, Marco Fabbiani and Piero Ugliengo of the Interdepartmental Center NIS – have discovered that the toxicity of crystalline silica is due to the presence of some special chemical structures, called “nearly free silanols”. The researchers have shown that these structures are formed on the surface of crystals during fracturing processes, explaining why only quartz reduced to fine powder is dangerous.
Silica, silicon dioxide, or quartz in its most common crystalline form, is a ubiquitous constituent of the Earth’s crust. Quartz is used in many industrial processes and several million workers are exposed to its dust every day. Breathing quartz dust into the workplace can cause serious illnesses such as silicosis, lung cancer and autoimmune diseases. Despite preventive measures, new materials and recent technologies (cutting and polishing of artificial marble, sandblasting of jeans, jewelry processing) have produced new and serious outbreaks of silicosis worldwide. Even today, occupational exposure to quartz dust remains the main cause of occupational respiratory diseases in the world.
Despite decades of studies, the molecular mechanisms that make crystalline silica toxic had not been clarified. The discovery of UniTO researchers revolutionizes the current knowledge on the mechanisms of toxicity of silica and will allow the development of processes to minimize the hazardousness of this material in the workplace.
Prof. Gianmario Martra, who made a fundamental contribution to this research, died while the work was being published. This last research is dedicated to him.