Ultrasensitive Label-Free Nanosensing and High-Speed Tracking of Single Proteins
Rights accessOpen Access
European Commission's projectLightNet - LightNet - Tracking the Coherent Light Path in Photosynthetic Networks (EC-H2020-670949)
: Label-free detection, analysis, and rapid tracking of nanoparticles is crucial for future ultrasensitive sensing applications, ranging from understanding of biological interactions to the study of size-dependent classical-quantum transitions. Yet optical techniques to distinguish nanoparticles directly among their background remain challenging. Here we present amplified interferometric scattering microscopy (aiSCAT) as a new all-optical method capable of detecting individual nanoparticles as small as 15 kDa proteins that is equivalent to half a GFP. By balancing scattering and reflection amplitudes the interference contrast of the nanoparticle signal is amplified 1 to 2 orders of magnitude. Beyond high sensitivity, a-iSCAT allows high-speed image acquisition exceeding several hundreds of frames-per-second. We showcase the performance of our approach by detecting single Streptavidin binding events and by tracking single Ferritin proteins at 400 frames-per-second with 12 nm localization precision over seconds. Moreover, due to its extremely simple experimental realization, this advancement finally enables a cheap and routine implementation of label-free all-optical single nanoparticle detection platforms with sensitivity operating at the single protein level.
CitationLiebel, M.; Hugall, J. T.; Hulst, N. F. V. Ultrasensitive Label-Free Nanosensing and High-Speed Tracking of Single Proteins. "Nano Letters", 17 Gener 2016, vol. 17, núm. 2, p. 1277-1281.