title: Single unlabeled protein detection on individual plasmonic nanoparticles.
abstract: The ultimate detection limit in analytic chemistry and biology is the single molecule. Commonly, fluorescent dye labels or enzymatic amplification are employed. This requires additional labeling of the analyte, which modifies the species under investigation and therefore influences biological processes. Here, we utilize single gold nanoparticles to detect single unlabeled proteins with extremely high temporal resolution. This allows for monitoring the dynamic evolution of a single protein binding event on a millisecond time scale. The technique even resolves equilibrium coverage fluctuations, opening a window into Brownian dynamics of unlabeled macromolecules. Therefore, our method enables the study of protein folding dynamics, protein adsorption processes, and kinetics as well as nonequilibrium soft matter dynamics on the single molecule level.
authors.affiliation: Institute for Physical Chemistry, University of Mainz, D-55128 Mainz, Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Ament
authors.forename: Janak
authors.initials: J
authors.lastname: Prasad
authors.forename: Andreas
authors.initials: A
authors.lastname: Henkel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schmachtel
authors.forename: Carsten
authors.initials: C
authors.lastname: Sönnichsen
mesh_terms: D000327:Adsorption; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D017510:Protein Folding; D011506:Proteins / Q000032:analysis*; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D011506:Proteins; D006046:Gold