Piezoelectric optical MEMS scanning fluorescence biosensor

J. Lo, E. S. Kim, M. A. Gundersen, Laura Marcu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Fluorescence spectroscopy plays a key role in a broad area of biological and medical applications. Development of fluorescence spectroscopy micro-devices will enable construction of fully integrated platforms for clinical diagnostics. We report the design, microfabrication and testing of a piezoelectric MEMS micro-grating as a part of the development of a combined spectral/time-resolved fluorescence biosensor for tissue characterization. For the design of the device, we simulated its theoretical performance using a piezoelectric multi-morph model with appropriate diffraction geometry. The microfabrication process was based on a SiN diaphragm (formed via KOH bulk-micromachining) on which the supporting layer of the micro-cantilevers was patterned. Piezoelectric ZnO was then magnetron sputtered and patterned on the cantilever as the physical source for linear actuation with low voltage (>32V). E-beam evaporation of aluminum formed the final reflective diffraction pattern as well as the electrode connections to the device units. The device actuation and displacement were characterized using LDDM (Laser Doppler Displacement Meter). Current cantilevers designed with 500 μm wide gratings (20 μm spacing) produced a maximum 38 μm bi-polar deflection at 3.5 kHz, with scanning from 350-650 nm at 26 nm resolution (10 nm with new 10 μm period prototype). The MEMS device was designed to be integrated with a fast response photomultiplier, and thus can be used with time-resolved fluorescence detection. Because in the case of time-resolved measurements, spectral resolution is not a crucial element, this configuration allows for the compensation of the geometric limitations (linear dispersion) of a micro-scale device that require wavelength differentiation and selection.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
EditorsT. Vo-Dinh, W.S. Grundfest, D.A. Benaron, G.E. Cohn
Pages103-110
Number of pages8
Volume5692
DOIs
StatePublished - 2005
Externally publishedYes
EventAdvanced Biomedical and Clinical Diagnostic Systems III - San Jose, CA, United States
Duration: Jan 23 2005Jan 26 2005

Other

OtherAdvanced Biomedical and Clinical Diagnostic Systems III
Country/TerritoryUnited States
CitySan Jose, CA
Period1/23/051/26/05

Keywords

  • Bulk microfabrication
  • Cantilever
  • Diffraction grating
  • Fluorescence detector
  • MEMS monochromator
  • Piezoelectric
  • VIS
  • ZnO

ASJC Scopus subject areas

  • Engineering(all)

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