Resonant mass biosensor for ultrasensitive detection of bacterial cells

Amit Gupta, Demir Akin, Rashid Bashir

Research output: Contribution to journalConference articlepeer-review


This paper describes a surface micromachined cantilever beam based oscillator detector for biological applications. This study used a novel microfabrication technique of merged epitaxial lateral overgrowth (MELO) and chemical mechanical polishing (CMP) to fabricate thin, low stress, single-crystal silicon cantilever beams. Vibration spectra of the cantilever beams, excited by thermal and ambient noise, was measured in air using a Digital Instrument Dimension 3100 Series scanning probe microscope (SPM). The cantilever beams were calibrated by obtaining the spring constant using the added-mass method. The sensors were used to detect the presence of Listeria innocua bacteria by applying increasing concentration of bacteria suspension on the same cantilever beam and measuring the resonant frequency changes in air. Cantilever beams were also used to detect the mass of the adsorbed antibodies and used to show selective capture of bacterial cells. The results indicate that the developed biosensor is capable of rapid and ultra-sensitive detection of bacteria and promises significant potential for enhancement of microbiological research and diagnostics.

Original languageEnglish (US)
Pages (from-to)21-27
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2003
Externally publishedYes
EventMicrofluidics, BioMEMS, and Medical Microsystems - San Jose, CA, United States
Duration: Jan 27 2003Jan 29 2003


  • Antibody-antigen interactions
  • Cantilever beam
  • Chemical mechanical polishing
  • Mass biosensor
  • Merged epitaxial lateral overgrowth
  • Resonant frequency
  • Silicon-on-insulator

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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