title: Singlet oxygen-induced apoptosis of cancer cells using upconversion fluorescent nanoparticles as a carrier of photosensitizer.
abstract: The photodynamic effect of upconversion nanoparticles loaded with a photosensitizer was studied on murine bladder cancer cells (MB49). Mesoporous silica was coated onto sodium yttrium fluoride upconversion nanocrystals to form a core-shell structure and then loaded with the photosensitizer zinc (II)-phthalocyanine into the porous silica. The nanoparticles displayed a uniform spherical shape with an average diameter of about 50 nm and showed good dispersibility in water. Intracellular uptake study in MB49 cells revealed a time- and concentration-dependent accumulation of these nanoparticles. Upon irradiation with 980-nm near-infrared light, their efficiency in activating the loaded zinc (II)-phthalocyanine to generate singlet oxygen molecules was confirmed in live cells. The cytotoxic effect of the released singlet oxygen from the nanoplatform was proven by cell viability assay, confocal microscopy, DNA agarose gel electrophoresis, cytochrome c-releasing assay, and prostate-specific antigen-enzyme-linked immunosorbent assay, all of which showed a strong photodynamic effect of the nanoparticles on MB49 cells. This suggests the efficacy of sodium yttrium fluoride upconversion nanoparticles as a carrier for photosensitizers and their use in photodynamic therapy of cancer and some other diseases.
  
  
  BACKGROUND
  In this study, the photodynamic effect of upconversion nanoparticles loaded with a photosensitizer was investigated on murine bladder cancer cells, with strongly positive results, which may pave its way to future clinical use in malignant tumors and potentially other diseases.
authors.affiliation: Division of Bioengineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore.
authors.forename: Huichen
authors.initials: H
authors.lastname: Guo
authors.forename: Haisheng
authors.initials: H
authors.lastname: Qian
authors.forename: Niagara Muhammad
authors.initials: NM
authors.lastname: Idris
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D053144:Cell Nucleus Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004337:Drug Carriers / Q000737:chemistry*; D005459:Fluorides; D006801:Humans; D007211:Indoles / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D054833:Isoindoles; D008297:Male; D050997:Nanomedicine / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009369:Neoplasms / Q000473:pathology*; D009942:Organometallic Compounds / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D016062:Porosity / Q000187:drug effects; D017430:Prostate-Specific Antigen / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry; D026082:Singlet Oxygen / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence; D015019:Yttrium; D017967:Zinc Compounds
chemical_list: D004337:Drug Carriers; D007211:Indoles; D054833:Isoindoles; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D017967:Zinc Compounds; C525362:sodium yttriumtetrafluoride; C052159:Zn(II)-phthalocyanine; D026082:Singlet Oxygen; D015019:Yttrium; D012822:Silicon Dioxide; D045304:Cytochromes c; D017430:Prostate-Specific Antigen; D005459:Fluorides