Theranostic UV activatable TiO2 nanoparticles as catalyst for selective tumor cell apoptosis

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.

Publication History

Publication Date:
23 April 2019 (online)