title: Single-image diffusion coefficient measurements of proteins in free solution.
abstract: Diffusion coefficient measurements are important for many biological and material investigations, such as studies of particle dynamics and kinetics, and size determinations. Among current measurement methods, single particle tracking (SPT) offers the unique ability to simultaneously obtain location and diffusion information about a molecule while using only femtomoles of sample. However, the temporal resolution of SPT is limited to seconds for single-color-labeled samples. By directly imaging three-dimensional diffusing fluorescent proteins and studying the widths of their intensity profiles, we were able to determine the proteins' diffusion coefficients using single protein images of submillisecond exposure times. This simple method improves the temporal resolution of diffusion coefficient measurements to submilliseconds, and can be readily applied to a range of particle sizes in SPT investigations and applications in which diffusion coefficient measurements are needed, such as reaction kinetics and particle size determinations.
authors.affiliation: Department of Physics, Washington University in St. Louis, Saint Louis, Missouri, USA.
authors.forename: Shannon Kian
authors.initials: SK
authors.lastname: Zareh
authors.forename: Michael C
authors.initials: MC
authors.lastname: DeSantis
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Kessler
authors.forename: Je-Luen
authors.initials: JL
authors.lastname: Li
authors.forename: Y M
authors.initials: YM
authors.lastname: Wang
mesh_terms: D004058:Diffusion; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000378:metabolism*; D057054:Molecular Imaging / Q000379:methods*; D010316:Particle Size; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013997:Time Factors
chemical_list: D012996:Solutions; D012997:Solvents; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins