Frustoconical porous microneedle for electroosmotic transdermal drug delivery

Daigo Terutsuki, Reiji Segawa, Shinya Kusama, Hiroya Abe, Matsuhiko Nishizawa

Research output: Contribution to journalArticlepeer-review


A truncated cone-shaped porous microneedle (PMN) made of poly-glycidyl methacrylate was studied as a minimally invasive tool for transdermal drug delivery. The transdermal electrical resistance of a pig skin was evaluated during the indentation of the PMNs, revealing that the frustoconical PMN (300 μm height) significantly reduced the resistance of the skin by expanding the stratum corneum without penetrating into the skin. A thin film of poly (2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) was grafted onto the inner wall of the microchannels of the frustoconical PMN to generate electroosmotic flow (EOF) upon current application in the direction of injection of the drug into the skin. Owing to the synergy of the expansion of the stratum corneum and the EOF-promotion, the PAMPS-modified frustoconical PMN effectively enhances the penetration of larger (over 500 Da) molecules, such as dextran (∼10 kDa).

Original languageEnglish
Pages (from-to)694-700
Number of pages7
JournalJournal of Controlled Release
Publication statusPublished - 2023 Feb


  • Electroosmosis
  • Frustoconical protrusion
  • Porous microneedle
  • Transdermal delivery

ASJC Scopus subject areas

  • Pharmaceutical Science


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