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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

(a) Graph showing droplet diameter before and after centrifugation of nanoemulsion M2 in cell-exposed nanoemulsion dispersed medium. (b) Integrated values of C8-PFTE 19F resonance peak in the supernatant and sediment of cell-exposed nanoemulsion dispersed medium. Error bars are standard deviation from mean of duplicate experiments.
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biosensors-03-00341-f008: (a) Graph showing droplet diameter before and after centrifugation of nanoemulsion M2 in cell-exposed nanoemulsion dispersed medium. (b) Integrated values of C8-PFTE 19F resonance peak in the supernatant and sediment of cell-exposed nanoemulsion dispersed medium. Error bars are standard deviation from mean of duplicate experiments.

Mentions: To assess physical stability during cell labeling, DLS analysis was performed on labeling medium containing nanoemulsion M2, which was exposed to macrophages for 24 h. Size and 19F NMR was recorded on supernatant and sediment after centrifugation. Overnight incubation of nanoemulsion M2 with macrophages has not shown any changes in droplet size and PDI (Appendix, Table S1). As shown in Figure 8(a), centrifugation of macrophage-exposed labeling medium has also not revealed any significant changes in droplet size at all the dilutions. Quantification of C8-PFTE signal in 19F NMR for supernatant and sediment has not shown any significant changes in integrated peak value for all the dilutions (Figure 8(b)) except at 4 mg/mL (p < 0.05). At this dilution, sediment showed around 10% higher C8-PFTE compared to supernatant. However, such a difference was not observed for other dilutions. Centrifugation was performed at 2,000 rpm for 10 min in consistence with the conditions experienced by labeled macrophages. These results evidently point to the high physical stability of nanoemulsion in cell culture and post-label processing conditions.


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

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

(a) Graph showing droplet diameter before and after centrifugation of nanoemulsion M2 in cell-exposed nanoemulsion dispersed medium. (b) Integrated values of C8-PFTE 19F resonance peak in the supernatant and sediment of cell-exposed nanoemulsion dispersed medium. Error bars are standard deviation from mean of duplicate experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00341-f008: (a) Graph showing droplet diameter before and after centrifugation of nanoemulsion M2 in cell-exposed nanoemulsion dispersed medium. (b) Integrated values of C8-PFTE 19F resonance peak in the supernatant and sediment of cell-exposed nanoemulsion dispersed medium. Error bars are standard deviation from mean of duplicate experiments.
Mentions: To assess physical stability during cell labeling, DLS analysis was performed on labeling medium containing nanoemulsion M2, which was exposed to macrophages for 24 h. Size and 19F NMR was recorded on supernatant and sediment after centrifugation. Overnight incubation of nanoemulsion M2 with macrophages has not shown any changes in droplet size and PDI (Appendix, Table S1). As shown in Figure 8(a), centrifugation of macrophage-exposed labeling medium has also not revealed any significant changes in droplet size at all the dilutions. Quantification of C8-PFTE signal in 19F NMR for supernatant and sediment has not shown any significant changes in integrated peak value for all the dilutions (Figure 8(b)) except at 4 mg/mL (p < 0.05). At this dilution, sediment showed around 10% higher C8-PFTE compared to supernatant. However, such a difference was not observed for other dilutions. Centrifugation was performed at 2,000 rpm for 10 min in consistence with the conditions experienced by labeled macrophages. These results evidently point to the high physical stability of nanoemulsion in cell culture and post-label processing conditions.

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