Fabrication of silicon oxide microneedles from macroporous silicon

Angel Rodríguez, David Molinero, Enrique Valera, Trifon Trifonov, Lluis F. Marsal, Josep Pallarès, Ramón Alcubilla

Research output: Contribution to journalArticlepeer-review


This paper presents a novel technique for silicon dioxide (SiO2) microneedle fabrication. Microneedles are hollow microcapillaries with tip diameters in the range of micrometers. They can be used in the fabrication of microsyringes. These structures can be of high interest in medical and biological applications, such as DNA injection, antibody manipulation and drug delivery, and cell manipulation. Fabrication process is based on electrochemical etching of n-type silicon in hydrofluoric acid (HF) solutions. Basic process flow and etching conditions that ensure a stable pore growth are described. These conditions also determine the geometry of the resulting microneedle structure. Microneedle arrays of different dimensions can be fabricated in a single run on the same wafer. In this work, microneedle arrays with pore diameters ranging from 2 to 5 μm, pore lengths from 30 to 140 μm and wall thicknesses in the range of 70-110 nm are reported.

Original languageEnglish (US)
Pages (from-to)135-140
Number of pages6
JournalSensors and Actuators, B: Chemical
Issue number1
StatePublished - Jul 24 2005
Externally publishedYes


  • Electrochemical etching
  • Macroporous silicon
  • Microneedles
  • Microsyringes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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