The growing application of materials containing TiO2 particles has led to an increased risk of human exposure, while a gap in knowledge about the possible adverse effects of TiO2 still exists. In this work, TiO2 particles of rutile, anatase, and their commercial mixture were exposed to various environments, including simulated gastric fluids and human blood plasma (both representing in vivo conditions), and media used in in vitro experiments. Simulated body fluids of different compositions, ionic strengths, and pH were used, and the impact of the absence or presence of chosen enzymes was investigated. The physicochemical properties and agglomeration of TiO2 in these media were determined. The time dependent agglomeration of TiO2 related to the type of TiO2, and mainly to the type and composition of the environment that was observed. The presence of enzymes either prevented or promoted TiO2 agglomeration. TiO2 was also observed to exhibit concentration-dependent cytotoxicity. This knowledge about TiO2 behavior in all the abovementioned environments is critical when TiO2 safety is considered, especially with respect to the significant impact of the presence of proteins and size-related cytotoxicity.

• Klíčová slova
• TiO2 particles, agglomeration, plasma, proteins, simulated gastric fluids,
• MeSH
• buněčné linie MeSH
• dárci krve MeSH
• fibroblasty účinky léků   metabolismus   MeSH
• koncentrace vodíkových iontů MeSH
• kovové nanočástice škodlivé účinky   chemie   MeSH
• krevní plazma metabolismus   MeSH
• krystalizace MeSH
• kultivační média metabolismus   MeSH
• lidé MeSH
• myši MeSH
• osmolární koncentrace MeSH
• povrchové vlastnosti MeSH
• sliny metabolismus   MeSH
• titan škodlivé účinky   chemie   metabolismus   MeSH
• velikost částic MeSH
• viabilita buněk účinky léků   MeSH
• voda metabolismus   MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kultivační média MeSH
• titan MeSH
• titanium dioxide MeSH Prohlížeč
• voda MeSH

Human data concerning exposure to nanoparticles are very limited, and biomarkers for monitoring exposure are urgently needed. In a follow-up of a 2016 study in a nanocomposites plant, in which only exhaled breath condensate (EBC) was examined, eight markers of oxidative stress were analyzed in three bodily fluids, i.e., EBC, plasma and urine, in both pre-shift and post-shift samples in 2017 and 2018. Aerosol exposures were monitored. Mass concentration in 2017 was 0.351 mg/m3 during machining, and 0.179 and 0.217 mg/m3 during machining and welding, respectively, in 2018. In number concentrations, nanoparticles formed 96%, 90% and 59%, respectively. In both years, pre-shift elevations of 50.0% in EBC, 37.5% in plasma and 6.25% in urine biomarkers were observed. Post-shift elevation reached 62.5% in EBC, 68.8% in plasma and 18.8% in urine samples. The same trend was observed in all biological fluids. Individual factors were responsible for the elevation of control subjects' afternoon vs. morning markers in 2018; all were significantly lower compared to those of workers. Malondialdehyde levels were always acutely shifted, and 8-hydroxy-2-deoxyguanosine levels best showed chronic exposure effect. EBC and plasma analysis appear to be the ideal fluids for bio-monitoring of oxidative stress arising from engineered nanomaterials. Potential late effects need to be targeted and prevented, as there is a similarity of EBC findings in patients with silicosis and asbestosis.

• Klíčová slova
• biomarkers, controls, exhaled breath condensate, nanoparticles, oxidative stress, plasma, urine, workers,
• Publikační typ
• časopisecké články MeSH