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Nat Med. 2012 Oct;18(10):1580-5. doi: 10.1038/nm.2933. Epub 2012 Sep 16.

In vivo photodynamic therapy using upconversion nanoparticles as remote-controlled nanotransducers.

Author information

1
Department of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore.

Abstract

Conventional photodynamic therapy (PDT) is limited by the penetration depth of visible light needed for its activation. Here we used mesoporous-silica-coated upconversion fluorescent nanoparticles (UCNs) as a nanotransducer to convert deeply penetrating near-infrared light to visible wavelengths and a carrier of photosensitizers. We also used the multicolor-emission capability of the UCNs at a single excitation wavelength for simultaneous activation of two photosensitizers for enhanced PDT. We showed a greater PDT efficacy with the dual-photosensitizer approach compared to approaches using a single photosensitizer, as determined by enhanced generation of singlet oxygen and reduced cell viability. In vivo studies also showed tumor growth inhibition in PDT-treated mice by direct injection of UCNs into melanoma tumors or intravenous injection of UCNs conjugated with a tumor-targeting agent into tumor-bearing mice. As the first demonstration, to the best of our knowledge, of the photosensitizer-loaded UCN as an in vivo-targeted PDT agent, this finding may serve as a platform for future noninvasive deep-cancer therapy.

PMID:
22983397
DOI:
10.1038/nm.2933
[Indexed for MEDLINE]

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