Aerosil ox50

The organic matrix of the experimental composites contained UDMA as base monomer, combined with TEGDMA or the newly synthesized 2EMATE-BDI (Figure 1) at 60 wt% or 40 wt%. The synthesis of the 2EMATE-BDI was performed by the reaction between 2-hydroxy-1-ethyl methacrylate with a difunctional isocyanate (1,3-bis (1- socyanato-1-methylethylbenzene) – BDI), according to the procedures described previously [15 ]. As an additional control group, 60 wt% of BisGMA was mixed with 40 wt% of TEGDMA. The photoinitiator system for each monomer mixture consisted of 0.2 wt% DMPA and 0.4 wt% DPI-PF6. Butylatedhydroxytoluene (BHT, in 0.1 wt%) was added as an inhibitor. The inorganic content (70 wt%) was composed of barium borosilicate glass 0.7 μm (Esstech, INC) and fumed silica (Aerosil OX50, Degussa) mixed at 95:5 wt%.
All photocuring procedures were carried out with a mercury arc lamp (Acticure, EXFO Acticure4000 UV Cure; Mississauga, Canada) filtered to 320–500 nm. The light source parameters and positioning was adjusted so that in all test configurations, the same irradiance (800 mW/cm²) was being delivered perpendicularly to the specimen.

For short-term and long-term exposures, plain polystyrene particles (PPP) of 20 and 200 nm (Thermo Scientific) were used. Particle uptake was investigated using red fluorescently labelled PPP of 25 nm, 200 nm, and 500 nm (FluoroMax red, Thermo Scientific). Silica particles Aerosil OX50 were obtained from Degussa.
PPP and Aerosil OX50 particles were applied to cells suspended in cell culture medium (DMEM + 10% FBS) after sonication in an Elmasonic S40 water bath (ultrasonic frequency: 37 kHz, 40 W, Elma) for 20 min.

Carboxyl PS (CPS) latex beads (20 and 200 nm; Invitrogen, Vienna, Austria), plain PS particles (PPS) (20 nm and 200 nm; ThermoScientific, Braunschweig, Germany), amine PS particles (AMI) 20 nm (Merck Chemicals and Life SCiences, Vienna, Austria) and 200 nm (Invitrogen), and amidine PS particles (APS) (20 nm and 200 nm, Invitrogen) were used. Aerosil^®200 (Aero200; 12 nm) and Aerosil^®OX50 (OX50; 40 nm) were obtained from Degussa, Frankfurt, Germany.
The human endothelial cell line EAhy926 (kind gift from Dr. C. J. Edgell) was cultured in Dulbecco minimal Eagle’s medium (DMEM), 10% fetal bovine serum (FBS), 2 mM L-glutamine and 1% penicillin/streptomycin. Human neuroblastoma cells SH-SY5Y (American Tissue and Cell Culture Collection, Manassas, VA, USA), used for the detection of intracellular [Ca²⁺] changes, were cultured in 90% DMEM/Ham’s F12, 10% FBS, 2 mM L-glutamine and 1% penicillin/streptomycin. All cells were cultured at 37 °C in a humid 95% air/5% CO₂ atmosphere.