title: Novel metal allergy patch test using metal nanoballs.
abstract: BACKGROUND
  Patch tests are often used in the clinical diagnosis of metal allergies. In currently available patch tests, high concentrations of metal salt solutions are used. However, diagnosis accuracy can be influenced not only by acute skin reactions to high concentrations of metal salt, but also by skin reactions to other components present in the patch or to pH changes. In this study, we developed Ni nanoparticles (termed "nanoballs") for use in patch-test solutions.
  
  
  RESULTS
  Highly soluble, spherical Ni nanoballs were prepared using plasma electrolysis. The Ni released from the nanoballs permeated through a dialysis membrane, and the nanoball-containing solution's pH was maintained constant. Ni ions were released slowly at low concentrations in a time-dependent manner, which contrasted the rapid release observed in the case of a commercial patch test. Consequently, in the new test system, reactions caused by high concentrations of metal salts were avoided.
  
  
  CONCLUSIONS
  By exploiting the high specific surface area of Ni nanoballs, we obtained an effective dissolution of Ni ions that triggered Ni allergy in the absence of direct contact between the nanoballs and mouse skin. This novel patch system can be applied to other metals and alloys for diagnosing various types of metal-induced contact dermatitis.
authors.affiliation: Department of Dentistry, Oral and Maxillofacial Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. tomoko_s@jichi.ac.jp.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sugiyama
authors.affiliation: Advanced Biomaterials Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan. uo.abm@tmd.ac.jp.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Uo
authors.affiliation: Advanced Biomaterials Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan. wada.abm@tmd.ac.jp.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Wada
authors.affiliation: Advanced Biomaterials Department, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan. hongo.abm@tmd.ac.jp.
authors.forename: Toshio
authors.initials: T
authors.lastname: Hongo
authors.affiliation: Department of Pathology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 131-8310, Japan. omagari.daisuke@nihon-u.ac.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Omagari
authors.affiliation: Department of Pathology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo, 131-8310, Japan. komiyama.kazuo@nihon-u.ac.jp.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Komiyama
authors.affiliation: Nakayamagumi Co. Ltd., North 19, East 1, Higashi-ku, Sapporo, Hokkaido, 065-8610, Japan. ht-sasaki@nakayamagumi.co.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Graduate School of Engineering, Hokkaido University, North 13, West 8, Sapporo, Hokkaido, 060-8628, Japan. takahash@ufml.caret.hokudai.ac.jp.
authors.forename: Heishichiro
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Dentistry, Oral and Maxillofacial Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. kusama34@iuhw.ac.jp.
authors.forename: Mikio
authors.initials: M
authors.lastname: Kusama
authors.affiliation: Department of Dentistry, Oral and Maxillofacial Surgery, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. mori-ora@jichi.ac.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Mori
mesh_terms: D000818:Animals; D064907:Diagnostic Uses of Chemicals; D006863:Hydrogen-Ion Concentration; D008810:Mice, Inbred C57BL; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods; D009532:Nickel / Q000737:chemistry* / Q000276:immunology* / Q000493:pharmacokinetics; D010328:Patch Tests / Q000295:instrumentation* / Q000379:methods*; D012867:Skin / Q000276:immunology; D013052:Spectrometry, X-Ray Emission / Q000379:methods
chemical_list: D064907:Diagnostic Uses of Chemicals; D009532:Nickel