Intracellular Trafficking of Transferrin-Conjugated Liposome/DNA Complexes by Confocal Microscopy

  • Lee Sang Mi (College of Pharmacy, Sookmyung Women's University) ;
  • Kim Jin-Seok (College of Pharmacy, Sookmyung Women's University)
  • Published : 2005.01.01


Intracellular trafficking of transferrin-conjugated dimethyldioctadecyl-ammonium bromide liposome $(T_f-liposome)/DNA$ complexes in HeLa cells was studied using the double-labeled fluorescence technique and confocal microscopy. The size of the $T_f-liposome/DNA$ complex was about 367 nm in diameter and the zeta-potential of it at a 5:1 (w/w) ratio was almost neutral. The intracellular pathway of the $T_f-liposome/DNA$ complex, noted as green (FITC), red (rhodamine) or yellow (FITC + rhodamine) fluorescence, was elucidated from the plasma membrane to the endosome (or lysosome), and finally to the nucleus. The results of this study indicate that plasmid DNA enters into the nucleus not only as a free form but as an associated form complexed with $T_f-liposome$. More interestingly, the $T_f-liposome$ undergoes a nuclear location in the form of ordered structures. This could be a very useful piece of information in designing a safe and advanced gene delivery system.



  1. Carlsson, J., Devin, H., and Axon, R., Protein thiolation and reversible protein-protein conjugation. Biochem. J., 173, 723- 737 (1978)
  2. Cheng, P., Receptor ligand-facilitated gene transfer: enhancement of liposome-mediated gene transfer and expression by transferrin. Human Gene Ther., 7(3), 275-282 (1996)
  3. Gao, X. and Huang, L., Cationic liposome-mediated gene transfer. Gene Ther., 2, 710-722 (1995)
  4. Godbey, W., Wu, T., Kenneth, K., and Mikos, A., Tracking the intracellular path of poly(ethylenimine)/DNA complexes for gene delivery. Proc. Natl. Acad. Sci. U.S.A., 96, 5177-5181 (1999)
  5. Mahato, R. I., Rolland, A., and Tomlinson, E., Cationic lipid-based gene delivery systems: pharmaceutical perspectives. Pharm. Res., 14(7), 853-859 (1997)
  6. Martin, F. J. and Papahadjopoulos, D., Irreversible coupling of immunoglobulin fragments to preformed vesicles: An improved method for liposome targeting. J. Biol. Chem., 257(1), 286- 288 (1982)
  7. Martin, F. J., Health, T. D., and New, R. R. C., Covalent attachment of proteins to liposomes, Liposomes: A practical approach. IRL Press, Oxford, pp. 163-182 (1990)
  8. Ogris, M., Walker, G.., Blessing, T., Kircheis, R., Wolschek, M., and Wagner, E., Tumor-targeted gene therapy: strategies for the preparation of ligand-polyethylene glycol-polyethylenimine/ DNA complexes. J. Control. Rel., 28, 173-181 (2003)
  9. Simoes, S., Pires, P., da Cruz M. T., Duzgunes N., and de Lima, M. C., Gene delivery by cationic liposome-DNA complexes containing transferrin or serum albumin. Methods in Enzymology, 373, 369-383 (2003)
  10. Szoka, F. and Papahadjopoulos, D., Procedure for preparation of liposomes with large internal aqueous space and high capture by reverse-phase evaporation. Proc. Natl. Acad. Sci. U.S.A., 75, 4194-4198 (1978)
  11. Thorstensen, K. and Romslo, I., The transferrin receptor: its diagnostic value and its potential as therapeutic target. Scand. J. Clin. Lab Invest. Suppl., 215, 113-120 (1993)
  12. Wagner, E., Curiel, D., and Cotton, M., Delivery of drugs, proteins and genes into cells using transferrin as a ligand for receptor-mediated endocytosis. Adv. Drug Del. Rev., 14, 113- 135 (1994)