Remotely adjustable check-valves with an electrochemical release mechanism for implantable biomedical microsystems

Tingrui Pan, Antonio Baldi, Babak Ziaie

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

In this paper, we present two remotely adjustable check-valves with an electrochemical release mechanism for implantable biomedical microsystems. These valves allow one to vary the opening pressure set-point and flow resistance over a period of time. The first design consists of a micromachined check-valve array using a SU-8 polymer structural layer deposited on the top of a gold sacrificial layer. The second design is based on a variable length cantilever beam structure with a gold sacrificial layer. The adjustable cantilever-beam structure is fabricated by gold thermo-compression bond of a thin silicon wafer over a glass substrate. In both designs, the evaporated gold can be electrochemically dissolved using a constant DC current via a telemetry link. In the first design the dissolution simply opens up individual outlets, while in the second design, gold anchors are sequentially dissolved hence increasing the effective length of the cantilever beam (reducing the opening pressure). A current density of 35 mA/cm2 is used to dissolve the gold sacrificial layers. Both gravity and syringe-pump driven flow are used to characterize the valve performance. A multi-stage fluidic performance (e.g. flow resistance and opening pressure) is clearly demonstrated.

Original languageEnglish (US)
Pages (from-to)385-394
Number of pages10
JournalBiomedical Microdevices
Volume9
Issue number3
DOIs
StatePublished - Jun 1 2007

Keywords

  • Glaucoma
  • Gold dissolution
  • Microfluidic
  • Microvalve
  • Wireless implantable microsystem

ASJC Scopus subject areas

  • Biomedical Engineering
  • Molecular Biology

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