Ultrasensitive detection of a protein by optical trapping in a photonic-plasmonic microcavity

Miguel A. Santiago-Cordoba, Murat Cetinkaya, Svetlana V. Boriskina, Frank Vollmer, Melik C. Demirel

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


Microcavity and whispering gallery mode (WGM) biosensors derive their sensitivity from monitoring frequency shifts induced by protein binding at sites of highly confined field intensities, where field strengths can be further amplified by excitation of plasmon resonances in nanoparticle layers. Here, we propose a mechanism based on optical trapping of a protein at the site of plasmonic field enhancements for achieving ultra sensitive detection in only microliter-scale sample volumes, and in real-time. We demonstrate femto-Molar sensitivity corresponding to a few 1000 s of macromolecules. Simulations based on Mie theory agree well with the optical trapping concept at plasmonic 'hotspots' locations.

Original languageEnglish (US)
Pages (from-to)629-638
Number of pages10
JournalJournal of Biophotonics
Issue number8-9
StatePublished - Aug 2012

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Materials Science
  • General Biochemistry, Genetics and Molecular Biology
  • General Engineering
  • General Physics and Astronomy


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