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Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design.

Patel SK, Williams J, Janjic JM - Biosensors (Basel) (2013)

Bottom Line: This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro.Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity.Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA. patels1@duq.edu.

ABSTRACT
This report describes novel perfluorocarbon (PFC) nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI). 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5-2.0 g/mL). This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm) and low polydispersity (<0.15), show a single peak in the 19F nuclear magnetic resonance spectrum at -71.4 ppm and possess high fluorine content. The droplet size and polydispersity remained unchanged after 160 days of follow up at three temperatures (4, 25 and 37 °C). Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

No MeSH data available.


Related in: MedlinePlus

Schematic of nanoemulsion exposure to cells, followed by removal of excess nanoemulsion by centrifugation. Low density of C8-PFTE makes the nanodroplet removal easier when centrifuged with cells.
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biosensors-03-00341-f007: Schematic of nanoemulsion exposure to cells, followed by removal of excess nanoemulsion by centrifugation. Low density of C8-PFTE makes the nanodroplet removal easier when centrifuged with cells.

Mentions: Macrophages were labeled with nanoemulsion M2 at different concentrations of C8-PFTE for 24 h. Unexposed macrophages were counted using Neubauer hemocytometer and serial dilutions were prepared. Luminescence was recorded after addition of CellTiter-Glo® analyte. Obtained luminescence values for serial dilutions were used to get a regression equation (Figure 6(b)). Using this equation, cell numbers were predicted for cells exposed to nanoemulsion M2. Labeled macrophages were subjected to 19F NMR analysis to quantify the loading efficiency. As shown in Figure 6(c), peak shape was unaltered in cells showing that C8-PFTE is metabolically stable. A dose dependent uptake of nanoemulsion M2 in macrophages was observed (Figure 6(d)). A high cell loading was observed (101119F atoms per cell) at a very low concentration of 2 mg/mL C8-PFTE. The obtained cell loading was comparable to our previous nanoemulsion with linear perfluoropolyether which contain a larger number of 19F atoms (40) per molecule [9]. Figure 7 shows a schematic of cell labeling with nanoemulsion and washing procedure employed. The proposed structure of the nanodroplet is also illustrated in Figure 7.


Cell Labeling for 19F MRI: New and Improved Approach to Perfluorocarbon Nanoemulsion Design.

Patel SK, Williams J, Janjic JM - Biosensors (Basel) (2013)

Schematic of nanoemulsion exposure to cells, followed by removal of excess nanoemulsion by centrifugation. Low density of C8-PFTE makes the nanodroplet removal easier when centrifuged with cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263580&req=5

biosensors-03-00341-f007: Schematic of nanoemulsion exposure to cells, followed by removal of excess nanoemulsion by centrifugation. Low density of C8-PFTE makes the nanodroplet removal easier when centrifuged with cells.
Mentions: Macrophages were labeled with nanoemulsion M2 at different concentrations of C8-PFTE for 24 h. Unexposed macrophages were counted using Neubauer hemocytometer and serial dilutions were prepared. Luminescence was recorded after addition of CellTiter-Glo® analyte. Obtained luminescence values for serial dilutions were used to get a regression equation (Figure 6(b)). Using this equation, cell numbers were predicted for cells exposed to nanoemulsion M2. Labeled macrophages were subjected to 19F NMR analysis to quantify the loading efficiency. As shown in Figure 6(c), peak shape was unaltered in cells showing that C8-PFTE is metabolically stable. A dose dependent uptake of nanoemulsion M2 in macrophages was observed (Figure 6(d)). A high cell loading was observed (101119F atoms per cell) at a very low concentration of 2 mg/mL C8-PFTE. The obtained cell loading was comparable to our previous nanoemulsion with linear perfluoropolyether which contain a larger number of 19F atoms (40) per molecule [9]. Figure 7 shows a schematic of cell labeling with nanoemulsion and washing procedure employed. The proposed structure of the nanodroplet is also illustrated in Figure 7.

Bottom Line: This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro.Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity.Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282, USA. patels1@duq.edu.

ABSTRACT
This report describes novel perfluorocarbon (PFC) nanoemulsions designed to improve ex vivo cell labeling for 19F magnetic resonance imaging (MRI). 19F MRI is a powerful non-invasive technique for monitoring cells of the immune system in vivo, where cells are labeled ex vivo with PFC nanoemulsions in cell culture. The quality of 19F MRI is directly affected by the quality of ex vivo PFC cell labeling. When co-cultured with cells for longer periods of time, nanoemulsions tend to settle due to high specific weight of PFC oils (1.5-2.0 g/mL). This in turn can decrease efficacy of excess nanoemulsion removal and reliability of the cell labeling in vitro. To solve this problem, novel PFC nanoemulsions are reported which demonstrate lack of sedimentation and high stability under cell labeling conditions. They are monodisperse, have small droplet size (~130 nm) and low polydispersity (<0.15), show a single peak in the 19F nuclear magnetic resonance spectrum at -71.4 ppm and possess high fluorine content. The droplet size and polydispersity remained unchanged after 160 days of follow up at three temperatures (4, 25 and 37 °C). Further, stressors such as elevated temperature in the presence of cells, and centrifugation, did not affect the nanoemulsion droplet size and polydispersity. Detailed synthetic methodology and in vitro testing for these new PFC nanoemulsions is presented.

No MeSH data available.


Related in: MedlinePlus