Using whispering gallery mode micro lasers for biosensing within undiluted serum

Tess Reynolds, Alexandre François, Nicolas Riesen, Michelle E. Turvey, Stephen J. Nicholls, Peter Hoffmann, Tanya M. Monro

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

2 Citations (Scopus)


Although whispering gallery mode (WGM) biosensors have shown tremendous potential, they are still yet to find practical use as biomedical diagnostic tools. This is primarily due to the nature of the interrogation mechanism itself which relies on indirect measurement of the binding of a specific biomolecule onto the sensor through the associated refractive index change. Since nonspecific binding cannot be differentiated from the specific interaction of interest, this can result in a high rate of false positive readings when the detection is performed in complex biological samples. Here we show that this inherent limitation can be solved using a relatively simple approach. This approach involves the development of a self-referenced biosensor consisting of two almost identically sized dye-doped polystyrene microspheres placed on adjacent holes at the tip of a suspended core optical fiber. Here self-referenced biosensing is demonstrated with the detection of Neutravidin in undiluted human serum samples. The fiber allows remote excitation and collection of the WGMs of the microspheres in a dip sensing setting. By taking advantage of surface functionalization techniques, one microsphere acts as a dynamic reference, compensating for nonspecific binding events, while the other microsphere is functionalized to detect the specific interaction. The almost identical size allows the two spheres to have virtually identical refractive index sensitivity and surface area. This ensures their responses to nonspecific binding and environmental changes are almost identical, whereby any specific changes such as binding events, can be monitored via the relative movement between the two sets of WGM peaks.

Original languageEnglish
Title of host publicationSPIE BioPhotonics Australasia
EditorsEwa M. Goldys, Mark R. Hutchinson
Number of pages8
ISBN (Electronic)9781510604346
Publication statusPublished - 1 Jan 2016
Externally publishedYes
EventSPIE BioPhotonics Australasia 2016 - Adelaide Convention Centre, North Terrace, Adelaide, Australia
Duration: 17 Oct 201619 Oct 2016

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE BioPhotonics Australasia 2016
CityNorth Terrace, Adelaide


  • Lasers
  • Microcavities
  • Sensing
  • Whispering Gallery Modes

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