title: Preparation of soluble stable C₆₀/human serum albumin nanoparticles via cyclodextrin complexation and their reactive oxygen production characteristics.
abstract: OBJECTIVE
  The stability of solutions of fullerene C₆₀ with human serum albumin (C₆₀/HSA) has not been studied in detail. In this study, we report on the preparation of stable C₆₀/HSA solutions that are formed via the formation of C₆₀/HP-β-CyD nanoparticles, i.e. by transferring C₆₀ molecules from HP-β-CyD to HSA molecules, and an investigation of the reactive oxygen species on the behavior of the resulting C₆₀/HSA.
  
  
  METHODS
  Structural and functional properties were examined by spectroscopic techniques, including circular dichroism (CD), fluorescent spectra (FI), and electron spin resonance spin-trapping method, and by cell viability test using A549 cells.
  
  
  RESULTS
  Aqueous C₆₀/HSA solutions with a small distribution size, excellent dispersion stability and a high dispersion concentration were obtained without the use of organic solvents. CD and FI spectra indicated that the HSA had undergone structural changes as the result of C₆₀/HSA formation. Binding experiments indicated that C₆₀/HSA had increased Site I and Site II-ligand binding capabilities. The HSA, in the form of C₆₀/HSA was, therefore, conformationally altered, and its binding capabilities were enhanced. Radical scavenging studies using the 1,1'-diphenyl-2-picrylhydrazyl radical showed that C₆₀/HSA had an increased antioxidant activity, compared to HSA alone. Further, C₆₀/HSA efficiently generated not only superoxide anion radicals O₂·- but also singlet oxygen ¹O₂ through photoirradiation. C₆₀/HSA showed cell toxicity characteristics after light irradiation, but no toxicity was observed in the absence of irradiation.
  
  
  CONCLUSIONS
  C₆₀/HSA not only has an excellent stability and antioxidant activity, but also has substantial phototoxicity properties. It thus appears that HSA can be used as a carrier of C₆₀in drug delivery systems for photodynamic therapy.
authors.affiliation: Faculty of Pharmacy, King Abdulaziz University, 80260 Jeddah 21589, Saudi Arabia; Faculty of Medicine, King Abdulaziz University, 80260 Jeddah 21589, Saudi Arabia.
authors.forename: Altaf
authors.initials: A
authors.lastname: Abdulmalik
authors.forename: Aldawsari
authors.initials: A
authors.lastname: Hibah
authors.forename: Banjar M
authors.initials: BM
authors.lastname: Zainy
authors.forename: Anraku
authors.initials: A
authors.lastname: Makoto
authors.forename: Iohara
authors.initials: I
authors.lastname: Daisuke
authors.forename: Otagiri
authors.initials: O
authors.lastname: Masaki
authors.forename: Uekama
authors.initials: U
authors.lastname: Kaneto
authors.forename: Hirayama
authors.initials: H
authors.lastname: Fumitoshi
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry; D000975:Antioxidants / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D003505:Cyclodextrins / Q000737:chemistry*; D045304:Cytochromes c / Q000378:metabolism; D017484:Dermatitis, Phototoxic; D004355:Drug Stability; D016166:Free Radical Scavengers / Q000494:pharmacology; D037741:Fullerenes / Q000737:chemistry*; D006801:Humans; D007660:Ketoprofen / Q000737:chemistry; D008024:Ligands; D053758:Nanoparticles; D010851:Picrates / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D012995:Solubility; D014859:Warfarin / Q000737:chemistry
chemical_list: D024322:Amino Acids, Aromatic; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D001713:Biphenyl Compounds; D003505:Cyclodextrins; D016166:Free Radical Scavengers; D037741:Fullerenes; D008024:Ligands; D010851:Picrates; D017382:Reactive Oxygen Species; D012709:Serum Albumin; D014859:Warfarin; D045304:Cytochromes c; D007660:Ketoprofen; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: 2-Hydroxypropyl-β-cyclodextrin; Fullerene; Human serum albumin; Photodynamic therapy