Ultrasensitive detection of a protein by optical trapping in a photonic-plasmonic microcavity.
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.
Materials Research Institute, 212 EES Bldg, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Miguel A
MA
Santiago-Cordoba
Murat
M
Cetinkaya
Svetlana V
SV
Boriskina
Frank
F
Vollmer
Melik C
MC
Demirel
D000818:Animals; D002417:Cattle; D006046:Gold / Q000737:chemistry; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D052898:Optical Tweezers; D017785:Photons; D012710:Serum Albumin, Bovine / Q000032:analysis* / Q000737:chemistry
D012710:Serum Albumin, Bovine; D006046:Gold