title: Real-time intracellular transport of gene nanocarriers studied by multiple particle tracking.
abstract: We used real-time multiple particle tracking to quantitatively characterize the type and rates of transport of gene nanocarriers within live cells. The heterogeneous cytoplasmic transport of polyethylenimine (PEI)/DNA gene carriers was quantified by tracking their mean-square displacements over time and classified into active and nonactive transport populations on the basis of their effective diffusivities versus time. Nonactive gene carriers frequently displayed hop-diffusion trajectories, suggesting a porous cytoplasmic network of flexible biopolymers or sequential attachment and detachment events. Microtubule-dependent active transport of gene carriers resulted in an effective diffusivity 30-fold greater than that of nonactive carriers (at a time scale of 3 s). Compared to nonactive carriers in control cells with intact microtubules, microtubule depolymerization enhanced short-range motion of gene carriers but resulted in similar long-range transport. Multiple particle tracking characterizes gene carrier transport in complex biological environments and, therefore, may be a useful tool in quantifying rate-limiting steps in gene delivery within cells and other biological media.
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University, 720 Rutland Ave., Baltimore, Maryland 21205, USA.
authors.forename: Junghae
authors.initials: J
authors.lastname: Suh
authors.forename: Denis
authors.initials: D
authors.lastname: Wirtz
authors.forename: Justin
authors.initials: J
authors.lastname: Hanes
mesh_terms: D000818:Animals; D001692:Biological Transport; D019556:COS Cells; D002522:Chlorocebus aethiops; D004247:DNA / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000648:ultrastructure*; D004058:Diffusion; D016503:Drug Delivery Systems / Q000379:methods*; D018014:Gene Transfer Techniques; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D042541:Intracellular Space / Q000378:metabolism / Q000648:ultrastructure*; D008856:Microscopy, Fluorescence / Q000379:methods; D009038:Motion; D043942:Nanotubes / Q000648:ultrastructure; D011094:Polyethyleneimine; D014162:Transfection / Q000379:methods*
chemical_list: D011094:Polyethyleneimine; D004247:DNA