Real-time quantitation of intracellular polycation/DNA nanocomplex transport: Evidence for directed motion

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Multiple particle tracking (MPT) was used to study the mechanism of gene delivery with a non-viral DNA delivery system. Movements of hundreds of individual fluorescent PEI/DNA nanocomplexes were tracked through COS-7 cells and their transport properties were quantified by calculating their mean-square displacements (MSD). Average MSDs of complexes did not change significantly over the first 5 h post-transfection. At a time scale of 10 s, MSD values ranged from 0.21 to 0.57 μm2, compared to < 0.32 μm2 for 6kb-sized naked DNA[1]. Velocities calculated for individual particles showed some moved as fast as 0.26 μm/s, while others were almost immobile. Interestingly, 35% of the complexes were transported in a directed fashion 0.5 h after transfection (rather than random diffusion), a phenomenon that could not be detected by other methods such as Fluorescence Recovery After Photobleaching (FRAP). The percentage of cells undergoing directed transport increased to 62% after 5 h. Studies such as these should allow the systematic optimization of the physicochemical properties of non-viral gene carriers for enhanced gene transfection efficacy.

Original languageEnglish (US)
Pages (from-to)548-549
Number of pages2
JournalAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
StatePublished - Dec 1 2002
EventProceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS) - Houston, TX, United States
Duration: Oct 23 2002Oct 26 2002


  • COS-7
  • Intracellular
  • Particle tracking
  • PEI

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics


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