title: Organosilane-Based Coating of Quartz Species from the Traditional Ceramics Industry: Evidence of Hazard Reduction Using In Vitro and In Vivo Tests.
abstract: The exposure to respirable crystalline silica (RCS), e.g. quartz, in industrial settings can induce silicosis and may cause tumours in chronic periods. Consequently, RCS in the form of quartz and cristobalite has been classified as human lung carcinogen category 1 by the International Agency for Research on Cancer in 1997, acknowledging differences in hazardous potential depending on source as well as chemical, thermal, and mechanical history. The physico-chemical determinants of quartz toxicity are well understood and are linked to density and abundance of surface silanol groups/radicals. Hence, poly-2-vinylpyridine-N-oxide and aluminium lactate, which effectively block highly reactive silanol groups at the quartz surface, have formerly been introduced as therapeutic approaches in the occupational field. In the traditional ceramics industry, quartz-containing raw materials are indispensable for the manufacturing process, and workers are potentially at risk of developing quartz-related lung diseases. Therefore, in the present study, two organosilanes, i.e. Dynasylan® PTMO and Dynasylan® SIVO 160, were tested as preventive, covalent quartz-coating agents to render ceramics production safer without loss in product quality. Coating effectiveness and coating stability (up to 1 week) in artificial alveolar and lysosomal fluids were first analysed in vitro, using the industrially relevant quartz Q1 as RCS model, quartz DQ12 as a positive control, primary rat alveolar macrophages as cellular model system (75 µg cm-2; 4 h of incubation ± aluminium lactate to verify quartz-related effects), and lactate dehydrogenase release and DNA strand break induction (alkaline comet assay) as biological endpoints. In vitro results with coated quartz were confirmed in a 90-day intratracheal instillation study in rats with inflammatory parameters as most relevant readouts. The results of the present study indicate that in particular Dynasylan® SIVO 160 (0.2% w/w of quartz) was able to effectively and stably block toxicity of biologically active quartz species without interfering with technical process quality of certain ceramic products. In conclusion, covalent organosilane coatings of quartz might represent a promising strategy to increase workers' safety in the traditional ceramics industry.
authors.affiliation: Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Ziemann
authors.affiliation: Instituto de Tecnología Cerámica-AICE, Universitat Jaume I, Campus Universitario Riu Sec, Avenida Vicent Sos Baynat, 12006 Castellón, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Escrig
authors.affiliation: Centro Ceramico di Bologna (CCB), Via Martelli, 26, 40138 Bologna, Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Bonvicini
authors.affiliation: Instituto de Tecnología Cerámica-AICE, Universitat Jaume I, Campus Universitario Riu Sec, Avenida Vicent Sos Baynat, 12006 Castellón, Spain.
authors.forename: Maria Jesús
authors.initials: MJ
authors.lastname: Ibáñez
authors.affiliation: Instituto de Tecnología Cerámica-AICE, Universitat Jaume I, Campus Universitario Riu Sec, Avenida Vicent Sos Baynat, 12006 Castellón, Spain.
authors.forename: Eliseo
authors.initials: E
authors.lastname: Monfort
authors.affiliation: Centro Ceramico di Bologna (CCB), Via Martelli, 26, 40138 Bologna, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Salomoni
authors.affiliation: Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Creutzenberg
mesh_terms: D000395:Air Pollutants, Occupational / Q000633:toxicity*; D000818:Animals; D002460:Cell Line; D006801:Humans; D007221:Industry; D008168:Lung / Q000187:drug effects; D016676:Macrophages, Alveolar / Q000187:drug effects; D016273:Occupational Exposure; D010316:Particle Size; D011791:Quartz / Q000008:administration & dosage / Q000633:toxicity*; D051381:Rats; D012822:Silicon Dioxide / Q000633:toxicity; D012829:Silicosis / Q000473:pathology; D013499:Surface Properties
chemical_list: D000395:Air Pollutants, Occupational; D011791:Quartz; D012822:Silicon Dioxide
keywords: coating of quartz; organosilane; quartz toxicity; rat alveolar macrophages; respirable crystalline silica; silanol groups; silicosis; traditional ceramics industry