Quantitating Intracellular Transport of Polyplexes by Spatio-Temporal Image Correlation Spectroscopy
Quantitatively understanding how nonviral gene delivery vectors (polyplexes) are transported inside cells is essential before they can be optimized for gene therapy and medical applications. In this study, we used spatio-temporal image correlation spectroscopy (ICS) to follow polymer-nucleic acid pa...
Saved in:
Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 102; no. 21; pp. 7523 - 7528 |
---|---|
Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
24.05.2005
National Acad Sciences |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Quantitatively understanding how nonviral gene delivery vectors (polyplexes) are transported inside cells is essential before they can be optimized for gene therapy and medical applications. In this study, we used spatio-temporal image correlation spectroscopy (ICS) to follow polymer-nucleic acid particles (polyplexes) of various sizes and analyze their diffusive-like and flow behaviors intracellularly to elucidate the mechanisms responsible for their transport. ICS is a quantitative imaging technique that allows the assessment of particle motion in complex systems, although it has not been widely used to date. We find that the internalized polyplexes are able to use microtubule motors for intracellular trafficking and exhibit different transport behaviors for short (< 10 s) versus long (≈60 s) correlation times. This motion can be explained by a memory effect of the microtubule motors. These results reveal that, although microtubule motor biases may be present for short periods of time, resulting in a net directional velocity, the overall long-term motion of the polyplexes is best described as a random walk-like process. These studies suggest that spatio-temporal ICS is a powerful technique for assessing the nature of intracellular motion and provides a quantitative tool to compare the transport of different objects within a living cell. |
---|---|
Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 To whom correspondence may be addressed. E-mail: mdavis@cheme.caltech.edu or sefraser@caltech.edu. Communicated by Robert Langer, Massachusetts Institute of Technology, Cambridge, MA, March 9, 2005 Author contributions: R.P.K., M.E.D., and S.E.F. designed research; R.P.K. performed research; R.P.K. and D.D.W. contributed new reagents/analytic tools; R.P.K., S.E.F., and M.E.D. analyzed data; and R.P.K., M.E.D., and S.E.F. wrote the paper. Abbreviations: ICS, image correlation spectroscopy; CD, cyclodextrin; PEI, polyethyleneimine. |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.0501950102 |