title: In vivo photodynamic therapy using upconversion nanoparticles as remote-controlled nanotransducers.
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.
authors.affiliation: Department of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore.
authors.forename: Niagara Muhammad
authors.initials: NM
authors.lastname: Idris
authors.forename: Muthu Kumara
authors.initials: MK
authors.lastname: Gnanasammandhan
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Paul C
authors.initials: PC
authors.lastname: Ho
authors.forename: Ratha
authors.initials: R
authors.lastname: Mahendran
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000528:radiation effects; D007259:Infrared Rays / Q000627:therapeutic use*; D008027:Light; D008545:Melanoma / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000627:therapeutic use*; D036103:Nanotechnology; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D026082:Singlet Oxygen; D014159:Transducers
chemical_list: D017319:Photosensitizing Agents; D026082:Singlet Oxygen