Minimally-invasive transepidermal potentiometry with microneedle salt bridge.
A commercial painless microneedle was filled with physiological saline agar, and this needle-based salt bridge was inserted into the skin (a piece of porcine skin and a flank skin of a live mouse) to make an electrical contact with its subepidermal region. The transepidermal potential (TEP), the potential difference between the skin surface and the subepidermal region, was measured using this inner electrode and a conventional agar electrode on the surface of the skin. Control of penetration depth of the inner electrode with a spacer and hydrophilic pretreatment with ozone plasma were found to be necessary for stable measurement. The TEP was reduced upon damages on the skin surface by tape stripping and acetone defatting, which indicated the fabricated needle electrode is useful for the minimally-invasive measurement of TEP and evaluation of skin barrier functions. Furthermore, we showed that the device integrating two electrodes into a single compact probe was useful to evaluate the local barrier functions and their mapping on a skin. This device could be a personal diagnostic tool in the fields of medicine and cosmetics in future.
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
Yuina
Y
Abe
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
Kuniaki
K
Nagamine
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
Mayu
M
Nakabayashi
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
Hiroyuki
H
Kai
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan.
Hirokazu
H
Kaji
Department of Dermatology, Graduate School of Medicine, Tohoku University, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Takeshi
T
Yamauchi
Department of Dermatology, Graduate School of Medicine, Tohoku University, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
Kenshi
K
Yamasaki
Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki, Aoba-ku, Sendai, 980-8579, Japan. nishizawa@biomems.mech.tohoku.ac.jp.
Matsuhiko
M
Nishizawa
D000279:Administration, Cutaneous; D000362:Agar; D000818:Animals; D004566:Electrodes; D004867:Equipment Design; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D009339:Needles; D011199:Potentiometry / Q000379:methods*; D012492:Salts / Q000737:chemistry; D012867:Skin / Q000187:drug effects*; D013552:Swine
D012492:Salts; D000362:Agar
Barrier function; In-vivo; Painless needle; Transepidermal potential