Microdroplets for integrated high sensitivity biosensors

Melikhan Tanyeri, Ian M. Kennedy

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

9 Scopus citations


The detection of single bacterial cells and novel absorbing labels has been demonstrated through optical resonances in microdroplets. The setup enables high throughput detection of single Escherichia coli (E. Coli) cells without any direct labeling although Rhodamine 6G (R6G) was used as the signal transduction mechanism. A micro droplet acts as an optical cavity that supports Morphology Dependent Resonances (MDRs) at wavelengths where the droplet circumference is an integer multiple of the emission wavelength. The cells inside the droplet have a direct effect on the fluorescence lasing spectrum of R6G fluorescence by means of scattering and local refractive index change. The change in the lasing spectrum can be observed at the concentrations where each droplet has as little as one cell. C 60 fluorescence quenching has also been demonstrated in microdroplets. R6G in ethanol (1μM) was used for the fluorescence spectrum measurements. Quenching of the optical resonances was observed when C 60 dissolved in ethanol was mixed with the R6G-Ethanol solution. Quenching can be observed at C 60 concentrations of 1 μM in the final solution. The background signal was also checked by repeating the experiment with only R6G and only C 60 in the solvent, assuring that the signal reduction was due to the addition of C 60 in to the solution. This quenching mechanism may have many applications in multiplexing in bioassays.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsD.V. Nicolau, U.R. Muller, J.M. Dell
Number of pages8
StatePublished - 2004
EventBioMEMS and Nanotechnology - Perth, WA, Australia
Duration: Dec 10 2003Dec 12 2003


OtherBioMEMS and Nanotechnology
CityPerth, WA


  • Bacteria
  • Carbon 60
  • Fluorescence
  • MDRs
  • Microdroplet
  • Quenching

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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