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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

1H NMR of C8-PFTE at 300 MHz. d6-Acetone-d6 set at 2.05 ppm is the reference.
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biosensors-03-00341-f009: 1H NMR of C8-PFTE at 300 MHz. d6-Acetone-d6 set at 2.05 ppm is the reference.

Mentions: To a solution of 1-octanol (2, 5.25 g, 40.35 mmol) in anhydrous ether (50.00 mL), triphenylphosphine (11.11 g, 42.37 mmol) was added, and the mixture stirred at room temperature for 15 min until the powder completely dissolved. The reaction mixture was then placed on an ice bath (0 °C) and diisopropylazodicarboxylate (DIAD) (8.71 mL, 44.38 mmol) was added dropwise. The addition was performed under argon atmosphere. During the addition, the solution changed color to pale yellow and a yellow precipitate formed. After the addition was complete, the reaction mixture was stirred for an additional 30 min on the ice bath and then perfluoro-tert-butanol (1, 10.00 g, 42.37 mmol) was added in one portion, and the resulting mixture was stirred for 1.5 h at room temperature. The crude reaction mixture was filtered over a short SiO2 column to remove the triphenylphosphine oxide precipitate. The filtrate was concentrated, redissolved in a small amount of ether and loaded on a SiO2 column. The product was eluted with a perfluorohexanes/ether (1:1 v/v) mixture and concentrated in vacuo. Removal of the unreacted perfluoro-tert-butanol under vacuum yielded the product (3) as a clear colorless oil (8.36 g, 59.5%). 1H NMR (300 MHz, d6-acetone) δ 4.12 (t, 2H, J = 6.3 Hz), 1.73 (qn, 2H, J = 6.6, 6.3 Hz), 1.46–1.30 (m, 10H), 0.88 (t, 3H, J = 6.75 Hz); 19F NMR (477 MHz, neat) δ −71.39 (s, 9F); 13C NMR (75.6 MHz, neat) δ 120.5 (q, J = 289.9 Hz), 80.1, 79.7, 70.3, 31.5, 25.1, 22.3, 13.3. Representative NMR spectra are shown in Appendix (Figure S1 and Figure S2).


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

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

1H NMR of C8-PFTE at 300 MHz. d6-Acetone-d6 set at 2.05 ppm is the reference.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00341-f009: 1H NMR of C8-PFTE at 300 MHz. d6-Acetone-d6 set at 2.05 ppm is the reference.
Mentions: To a solution of 1-octanol (2, 5.25 g, 40.35 mmol) in anhydrous ether (50.00 mL), triphenylphosphine (11.11 g, 42.37 mmol) was added, and the mixture stirred at room temperature for 15 min until the powder completely dissolved. The reaction mixture was then placed on an ice bath (0 °C) and diisopropylazodicarboxylate (DIAD) (8.71 mL, 44.38 mmol) was added dropwise. The addition was performed under argon atmosphere. During the addition, the solution changed color to pale yellow and a yellow precipitate formed. After the addition was complete, the reaction mixture was stirred for an additional 30 min on the ice bath and then perfluoro-tert-butanol (1, 10.00 g, 42.37 mmol) was added in one portion, and the resulting mixture was stirred for 1.5 h at room temperature. The crude reaction mixture was filtered over a short SiO2 column to remove the triphenylphosphine oxide precipitate. The filtrate was concentrated, redissolved in a small amount of ether and loaded on a SiO2 column. The product was eluted with a perfluorohexanes/ether (1:1 v/v) mixture and concentrated in vacuo. Removal of the unreacted perfluoro-tert-butanol under vacuum yielded the product (3) as a clear colorless oil (8.36 g, 59.5%). 1H NMR (300 MHz, d6-acetone) δ 4.12 (t, 2H, J = 6.3 Hz), 1.73 (qn, 2H, J = 6.6, 6.3 Hz), 1.46–1.30 (m, 10H), 0.88 (t, 3H, J = 6.75 Hz); 19F NMR (477 MHz, neat) δ −71.39 (s, 9F); 13C NMR (75.6 MHz, neat) δ 120.5 (q, J = 289.9 Hz), 80.1, 79.7, 70.3, 31.5, 25.1, 22.3, 13.3. Representative NMR spectra are shown in Appendix (Figure S1 and Figure S2).

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