title: Photodynamic therapy with hyperbranched poly(ether-ester) chlorin(e6) nanoparticles on human tongue carcinoma CAL-27 cells.
abstract: BACKGROUND
  Hyperbranched polymers represent a new class of drug-delivery vehicle that can be used to prepare nanoparticles with uniform size distribution.
  
  
  METHODS
  In this study we prepared covalent conjugates between the photosensitizer chlorin(e6) and hyperbranched poly(ether-ester), HPEE. HPEE-ce6 nanoparticles were synthesized by carbodiimide-mediated reaction between HPEE and ce6, and characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), and transmission electron microscopy (TEM). The uptake and phototoxicity of HPEE-ce6 nanoparticles towards human oral tongue cancer CAL-27 cells was detected by confocal laser scanning microscopy (CLSM) and MTT assay, respectively.
  
  
  RESULTS
  The absorption peak of HPEE-ce6 nanoparticles was red-shifted 12-nm compared with ce6, and TEM showed uniform nanoparticles with a diameter of 50-nm. HPEE-ce6 nanoparticles were taken up by CAL-27 cells after 4h incubation and localized in the cytoplasm. The MTT assay showed a significantly (P<0.05) higher phototoxicity compared to free ce6 after 12 J/cm² of 660-nm laser illumination.
  
  
  CONCLUSIONS
  This is the first time to our knowledge that hyperbranched polymers have been used in PDT drug delivery.
authors.affiliation: Ninth People's Hospital affiliated to Shanghai Jiaotong University Medical College, School of Stomatology, Department of Oral Maxillofacial Surgery, Shanghai Institute of Stomatology, Shanghai Key Point Laboratory of Stomatology, Shanghai 200011, China.
authors.forename: Pingping
authors.initials: P
authors.lastname: Li
authors.forename: Guoyu
authors.initials: G
authors.lastname: Zhou
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Zhu
authors.forename: Guolin
authors.initials: G
authors.lastname: Li
authors.forename: Peng
authors.initials: P
authors.lastname: Yan
authors.forename: Linyue
authors.initials: L
authors.lastname: Shen
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D045744:Cell Line, Tumor; D002470:Cell Survival; D002735:Chlorophyllides; D006801:Humans; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000627:therapeutic use*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology* / Q000627:therapeutic use; D011166:Porphyrins / Q000494:pharmacology* / Q000627:therapeutic use; D014062:Tongue Neoplasms / Q000188:drug therapy*
chemical_list: D002735:Chlorophyllides; D017319:Photosensitizing Agents; D011166:Porphyrins; C062985:phytochlorin