Formation of polymer microneedle arrays using soft lithography

Yoshimichi Ami, Hiroto Tachikawa, Naoki Takano, Norihisa Miki

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


We demonstrate the fabrication of polymer microneedle arrays using soft lithography. A photomask was designed to use Fresnel diffraction of UV light to create sharp, tapered hollows in SU-8, a negative photoresist, after development. Polymer microneedles were formed using these SU-8 structures as a mold. These polymer needles may be applicable as flexible electrodes in brain-machine interfaces because they are more likely to survive movement of the skin than conventional brittle silicon needles. Similar needles, made from medicinal substances, could be used for transdermal drug administration. For these applications, the needles must be long, sharp, and stiff enough to penetrate the stratum corneum (∼20 m in thickness) and reach the viable epidermis (200-300 m in thickness), but must not reach the dermis, which contains sensitive nerve endings. We successfully manufactured 2020 microneedle arrays of polydimethylsiloxane with a needle length of 200 m. We experimentally verified that these manufactured electrodes successfully penetrated the stratum corneum of a cultured skin.

Original languageEnglish
Article number011503
JournalJournal of Micro/Nanolithography, MEMS, and MOEMS
Issue number1
Publication statusPublished - 2011 Jan 1


  • brain-machine interfaces
  • drug delivery
  • microfabrication
  • microneedles
  • polymers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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