Liposomes confocal laser scanning microscopy

Figure 3 Binding and internalization of different liposomal formulations by bone marrow-derived dendritic cells (BmDQ from mice. BmDC were incubated for one hour with liposomes at 37 C and liposome uptake was analyzed by confocal laser scanning microscopy.

M. E. M. J. van Kuyk-Meuwissen, H. E. Junginger, and J. A. Bouwstra, Interactions between liposomes and human skin in vitro, a confocal laser scanning microscopy study, Biochim. Biophys. Acta 7377 13-39 (1998). 

Verma, D.D., Verma, S., Blume, G. et al. Liposomes increase skin penetration of entrapped and non-entrapped hydrophilic substances into human skin a skin penetration and confocal laser scanning microscopy study. Eur. J. Pharm. Biopharm. 2003 55 271-7. 

Fig. 10.5 Protocol for measurement of the mucoadhesive behavior of polymer-coated liposomes with confocal laser scanning microscopy (CLSM)...

Fig. 10.6 Confocal laser scanning microscopy photographs of various parts of the intestinal tract of the rat at 2 h after intragastric administration of ssCS-Lips (taken from Takeuchi et al. 2005a). The measured mean diameter is 281.2 nm. The formulation of liposome is DSPC DCP cholesterol = 8 2 1...

TAT-peptide modified liposomes were prepared and cellular association and intracellular distribution of (double) fluorescently labelled particles were assessed by flow cytometry and confocal laser scanning microscopy. 

Fig. 2. Intracellular localization of TAT-liposomes. OVCAR-3 cells are incubated with 150 nmol of double fluorescently labelled TAT-liposomes for 1 h and subsequently incubated for 1 h (a) or 23 h (b) in liposomes-free medium. Thirty minutes before visualization the endocytic pathway is labelled with Lysotracker Red. Live cell imaging is performed with confocal laser scanning microscopy. Double labelled liposomes are used to study the integrity of the liposome during the uptake process co-localization of both liposomal labels would indicate that the liposomes are intact. 1 h both liposomal labels are localized at the plasma membrane, which represent intact cell-bound TAT-liposomes. The electronically merged image clearly shows lack of co-localization with the endocytic pathway marker, Lysotracker Red. This opposite to the 24 h incubation, both liposomal labels can be seen intracellularly in a punctuate pattern. In the electronically merged image, co-localization with Lysotracker Red is clearly visible. This indicates that the TAT-peptide modified liposomes bind to the plasma membrane and after internalization are present in endocytic vesicles. Therefore, we conclude that the liposomes are internalized by endocytosis. (Reproduced from (12) with permission from Elsevier Science)...

In a subsequent study, van Hal et al. [40] reported that a decrease in cholesterol content in liquid state bilayers, which increases bilayer fluidity, resulted in an increase in estradiol transport across SC. With confocal laser scanning microscopy, Meuwissen et al. examined the diffusion depth of gel- vs. liquid-state liposomes labeled with fluorescein-dipalmitoylphosphatidylethanolamine (fluorescein-DPPE) with human skin in vitro [41] (Figure 3) and rat skin in vivo [42] and found that the lipophilic label when applied in liquid-state bilayers onto the skin penetrated deeper into the skin than when applied in gel-state liposomes. Recently, Fresta and Puglisi [43] reported that corticosteroid dermal delivery with skin-lipid liposomes was more effective than delivery with phospholipid vesicles, both with respect to higher drug concentrations in deeper skin layers and therapeutic effectiveness. This is a very surprising result, because skin lipid liposomes are rigid and form stacks of lamellae on the surface of the skin [44]. From the previously mentioned studies it seems clear that the thermodynamic state of the bilayer plays a crucial role in the effect of vesicles on dmg transport rate across skin in vitro. 

In skin research, drug and chemical targeting to various layers of skin is of great interest. For this piupose, various approaehes have been tried. Confocal laser scanning microscopy has been employed to study the influence of permeant lipophilicity and vehicle composition on local chemical acciunulation (Grams et al., 2003). In these studies, fluorescently labeled liposomes were applied on skin in vivo, and the penetration pathway and penetration depth of the lipophflie fluorescent label into the skin was visualized by confocal laser scanning microscopy (Van Kuijk-Meuwis-sen et al., 1998). 

Uster, P. S., Working, P. K. and Vaage, J., Pegylated liposomal doxorubicin (DOXIL , CAELYX ) distribution in tumour models observed with confocal laser scanning microscopy, Int. J. Pharm., 162, 77-86 (1998). 

Mady, M. M., Ghannam, M. M., Khahl, W. A., MiiUer, R., and Fahr, A. 2009. Efficiency of cytoplasmic delivery by non-cationic liposomes to cells in vitro A confocal laser scanning microscopy study. Phys Med 25 88-93. 

Moller, T., Confocal Laser Scanning Microscopy and its Application in Liposomal Research, in Particle and Surface Characterization Methods, Eds. Muller, R. H., Mehnert, W., Medpharm Scientific Publishers, Stuttgart, 1997, Chpt.6, pp.85-98. 

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