Core-shell magnetite-silica composite nanoparticles enhancing DNA damage induced by a photoactive platinum-diimine complex in red light

Lack of solubility under physiological conditions poses an additional risk for toxicity and side effects for intravenous delivery of the photodynamic therapeutic agent in vivo. Employing magnetite-silica composite nanoparticles as carriers of the photodynamic therapeutic agents may be a promising way to solve the problem. In this study, core-shell magnetite-silica composite nanoparticles were prepared by a sol–gel method, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering, then they were used as carriers of a photoactive platinum diimine complex. The interactions of the photosensitizer-loaded magnetic composite nanoparticles with DNA in red light were monitored by agarose-gel electrophoresis. The results suggest that high doses of magnetite-silica composite nanoparticles might facilitate the transformation of covalently closed circular (ccc)-DNA band to open circular (oc)-DNA band though they are harmless to DNA at their low concentrations, therefore enhancing the extent of DNA damage caused by the metal complex in red light.

Graphical abstractCore-shell magnetite-silica composite nanoparticles were prepared and used as carriers of a photoactive platinum diimine complex. The interactions of the photosensitizer-loaded nanoparticles with DNA suggest that high doses of nanoparticles might damage DNA, therefore enhancing the extent of DNA damage caused by the metal complex in red light.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Composite nanoparticles were used as carriers of a photosensitizer. ► High doses of magnetite-silica composite nanoparticles might damage DNA. ► The composite nanoparticles enhance the DNA damage induced by the photosensitizer.