Metal oxide nanoparticles (NP) like titanium dioxide (TiO2) are taken up by cells via endocytosis within a few minutes after exposition. Endocytosis
of NP is known to be higher in malignant cells compared to benign cells. Preliminary
work showed that functionality of TiO2-NP mainly depends on their physical properties. Our aim was to examine the potential
of theranostic TiO2-NP in human cells.
Fluorescence-labelled TiO2-NP were dispersed in the organic acid FIW1 and pre-activated by UVC light. Polycarboxylate
ether served as an inert stabilizer for the NP dispersion. FaDu, HLaC78 and non-malignant
cells (fibroblasts and MSC) were then exposed to the dispersion for 24h. Besides physicochemical
characterization, the MTT assay was performed for toxicological analysis. Cells incubated
with non-photoactivated TiO2-NP served as control.
Fluorescent TiO2-NP were preferably taken up by FaDu and HLaC78 cells compared to fibroblasts and
MSC. Only after UV pre-activation the NP dispersion showed a high toxicity in tumor
cells which was not achieved in fibroblasts and MSC even at high doses. Without UV
activation, the dispersion was non-toxic. NP-free medium supernatant showed certain
antitumoral effects as well.
Inactive fluorescence-labelled TiO2-NP are non-toxic and selectively taken up by tumor cells via endocytosis. TiO2-NP act as photocatalysts for the synthesis of a tumor-toxic substance derived from
FIW1 acid. NP themselves represent herein the catalyst without intrinsic toxicity.
The combination of fluorescence-labelling and catalytic potential make TiO2-NP a promising theranostic agent.
