Discoloration at anatase titanium dioxide surfaces by organic contamination

Clark, William C.; Broadhead, Peter

doi:10.1002/jctb.5020210403

Cited by 2 publications

(2 citation statements)

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“…While catechol molecules attach very strongly by bidentate polar covalent bonds, other hydroxyl groups attach to the TiO 2 surface by looser bidentate or monodentate bonds (15–20, 24). The doxorubicin molecule falls into the later category.…”

Section: Resultsmentioning

confidence: 99%

“…Below 20 nm the physical strain on the titanium-oxygen bonds on the nanoparticle surface causes high reactivity: these bonds can be broken easily to form stable polar covalent bonds with hydroxyl groups of catechol ligands such as dopamine and Alizarin Red S (10–14). At the same time, surface TiO 2 molecules form less stable bonds with other hydroxyl group -containing molecules (15–20). We found that the interaction between the TiO 2 surface and doxorubicin is relatively labile and is pH-dependent and show several lines of evidence for doxorubicin dissociation from nanocomposites inside cells.…”

Section: Introductionmentioning

confidence: 99%

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Nanocarriers Enhance Doxorubicin Uptake in Drug-Resistant Ovarian Cancer Cells

et al. 2012

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Resistance to anthracyclines and other chemotherapeutics due to P-glycoprotein (PGP)-mediated export is a frequent problem in cancer treatment. Here we report that iron oxide-titanium dioxide core-shell nanocomposites can serve as efficient carriers for doxorubicin to overcome this common mechanism of drug resistance in cancer cells. Doxorubicin nanocarriers (DNCs) increased effective drug uptake in drug-resistant ovarian cells. Mechanistically, doxorubicin bound to the TiO2 surface by a labile bond that was severed upon acidification within cell endosomes. Upon its release doxorubicin traversed the intracellular milieu and entered the cell nucleus by a route that evaded PGP-mediated drug export. Confocal and x-ray fluorescence microscopy with flow cytometry were used to demonstrate the ability of DNC to modulate transferrin uptake and distribution in cells. Increased transferrin uptake occurred through clathrin-mediated endocytosis, indicating that nanocomposites and DNCs may both interfere with removal of transferrin from cells. Together, our findings show that DNCs not only provide an alternative route of delivery of doxorubicin to PGP-over-expressing cancer cells, but may also boost the uptake of transferrin-tagged therapeutic agents.

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Section: Resultsmentioning

confidence: 99%