title: Label-free, all-optical detection, imaging, and tracking of a single protein.
abstract: Optical detection of individual proteins requires fluorescent labeling. Cavity and plasmonic methodologies enhance single molecule signatures in the absence of any labels but have struggled to demonstrate routine and quantitative single protein detection. Here, we used interferometric scattering microscopy not only to detect but also to image and nanometrically track the motion of single myosin 5a heavy meromyosin molecules without the use of labels or any nanoscopic amplification. Together with the simple experimental arrangement, an intrinsic independence from strong electronic transition dipoles and a detection limit of <60 kDa, our approach paves the way toward nonresonant, label-free sensing and imaging of nanoscopic objects down to the single protein level.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Ortega Arroyo
authors.forename: J
authors.initials: J
authors.lastname: Andrecka
authors.forename: K M
authors.initials: KM
authors.lastname: Spillane
authors.forename: N
authors.initials: N
authors.lastname: Billington
authors.forename: Y
authors.initials: Y
authors.lastname: Takagi
authors.forename: J R
authors.initials: JR
authors.lastname: Sellers
authors.forename: P
authors.initials: P
authors.lastname: Kukura
mesh_terms: D000818:Animals; D004867:Equipment Design; D051379:Mice; D008857:Microscopy, Interference / Q000295:instrumentation*; D009038:Motion; D015879:Myosin Subfragments / Q000032:analysis* / Q000648:ultrastructure; D061848:Optical Imaging / Q000295:instrumentation*
chemical_list: D015879:Myosin Subfragments