The RGB LED panel was made ad hoc, and configured for solar simulation white light (including the absorption spectra of the nanoparticles: 390–410). No heat was detected at the working distance. The retina of the albino male Wistar rats were not affected under these conditions, because the intensity and time of the applied irradiation was lower than the regular fluorescent lamp bulb in the room (216.65 W/m2) [34].

TiO₂ NPs appeared to be more toxic to nematode Caenorhabditis elegans than submicron-sized TiO_2.  At a concentration of 1 mg/l, 7 nm particles affected its fertility and survival rate and were more toxic than 20 nm anatase particles. Similarly, Hu et al. showed that rutile particles (10–20 nm), at concentrations above 1 g/kg soil, can be bio-accumulated in earthworms, where they induce oxidative stress, inhibit the activity of cellulase and induce DNA and mitochondrial damage.

Assessment of biocompatibility in prokaryotic cells