title: A core-shell-shell nanoplatform upconverting near-infrared light at 808 nm for luminescence imaging and photodynamic therapy of cancer.
abstract: Upconversion nanoparticles (UCNPs) have been extensively explored for photodynamic therapy (PDT) and imaging due to their representative large anti-Stokes shifts, deep penetration into biological tissues, narrow emission bands, and high spatial-temporal resolution. Conventional UCNP-based PDT system, however, utilizes exitation at 980 nm, at which water has significant absorption, leading to a huge concern that the cell killing effect is from the irradiation due to overheating effect. Here we report an efficient nanoplatform using 808-nm excited NaYbF4:Nd@NaGdF4:Yb/Er@NaGdF4 core-shell-shell nanoparticles loaded with Chlorin e6 and folic acid for simultaneous imaging and PDT. At this wavelength, the absorption of water is minimized. High energy transfer efficiency is achieved to generate cytotoxic singlet oxygen. Our nanoplatform effectively kills cancer cells in concentration-, time-, and receptor-dependent manners. More importantly, our nanoplatform is still able to efficiently generate singlet oxygen beneath 15-mm thickness of muscle tissue but 980 nm excitation cannot, showing that a higher penetration depth is achieved by our system. These results imply that our nanoplatform has the ability to effectively kill intrinsic tumor or the center of large tumors through PDT, which significantly improves the anticancer efficacy using UCNP-based PDT system and broadens the types of tumors that could be cured.
authors.affiliation: 1] Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR [2] City University of Hong Kong Shenzhen Research Institute, Shenzhen, P. R. China.
authors.forename: Fujin
authors.initials: F
authors.lastname: Ai
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong SAR.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ju
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR.
authors.forename: Xiaoman
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong SAR.
authors.forename: Xian
authors.initials: X
authors.lastname: Chen
authors.affiliation: 1] Department of Physics and Materials Science, City University of Hong Kong, Kowloon Tong, Hong Kong SAR [2] City University of Hong Kong Shenzhen Research Institute, Shenzhen, P. R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: 1] Department of Biology and Chemistry, City University of Hong Kong, Kowloon Tong, Hong Kong SAR [2] City University of Hong Kong Shenzhen Research Institute, Shenzhen, P. R. China.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Zhu
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D006801:Humans; D007259:Infrared Rays; D049449:Luminescence; D057054:Molecular Imaging; D053758:Nanoparticles; D009369:Neoplasms / Q000175:diagnosis / Q000628:therapy; D010778:Photochemotherapy