Optical microcavities are high sensitivity transducers able to detect single nanoparticles and molecules. However, the specificity of detection is dependent on the availability of an appropriate targeting moiety with minimal cross-reactivity. In the present work, an alternative approach is shown. Namely, using biotin-functionalized toroidal microcavities, the dissociation constant of biotin to two different streptavidin complexes (free and polystyrene bead) is determined. Based on the difference in affinity and in mass transport, the two complexes are identified from a mixture. By leveraging information in the binding site, improved specificity can be achieved.
© 2012 Optical Society of America
Original Manuscript: January 17, 2012
Revised Manuscript: March 5, 2012
Manuscript Accepted: March 12, 2012
Published: May 9, 2012
Vol. 7, Iss. 7 Virtual Journal for Biomedical Optics
C. Shi, S. Mehrabani, and A. M. Armani, "Leveraging bimodal kinetics to improve detection specificity," Opt. Lett. 37, 1643-1645 (2012)