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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

Physical characterization of M1 and M2 nanoemulsions using dynamic light scattering. (a) Representative size and (b) zeta potential distribution of M1 (black) and M2 (red) nanoemulsions. (c) Long term storage stability of M2 nanoemulsion and (d) M1 nanoemulsion at 4, 25 and 37 °C assessed by droplet size measurements. The error bars in panels C and D represent half width of polydispersity index (PDIw/2).
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biosensors-03-00341-f005: Physical characterization of M1 and M2 nanoemulsions using dynamic light scattering. (a) Representative size and (b) zeta potential distribution of M1 (black) and M2 (red) nanoemulsions. (c) Long term storage stability of M2 nanoemulsion and (d) M1 nanoemulsion at 4, 25 and 37 °C assessed by droplet size measurements. The error bars in panels C and D represent half width of polydispersity index (PDIw/2).

Mentions: Droplet size and zeta potential showed mono-modal distribution (Figure 5(a,b)) indicating the absence of large and small droplets. The average droplet size and PDI were around 180 and 0.2 for nanoemulsion M1 while nanoemulsion M2 showed a reduced droplet size and PDI around 130 nm and 0.15 respectively (Figure 5(a,c)). This reduced droplet size of C8-PFTE nanoemulsion (M2) is consistent with the sonicated nanoemulsions. Average zeta potential values for nanoemulsions M1 and M2 were negative, −5 to −7 mV (Figure 5(b)). For stable colloidal preparations, large zeta potential values (>±30 mV) are preferred to ensure repulsion between the droplets [31]. However, this requirement is not necessary for nanoemulsions prepared with Pluronic® nonionic surfactants. Pluronics provide stabilization via steric hindrance rather than charge repulsion and the observed zeta potential values are consistent with earlier reported values [8]. Storage stability was evaluated at 4, 25 and 37 °C by analyzing nanoemulsion samples at regular time intervals using DLS. Both formulations were shown to be stable for at least 160 days at all temperatures tested (Figure 5(c,d)).


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

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

Physical characterization of M1 and M2 nanoemulsions using dynamic light scattering. (a) Representative size and (b) zeta potential distribution of M1 (black) and M2 (red) nanoemulsions. (c) Long term storage stability of M2 nanoemulsion and (d) M1 nanoemulsion at 4, 25 and 37 °C assessed by droplet size measurements. The error bars in panels C and D represent half width of polydispersity index (PDIw/2).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-03-00341-f005: Physical characterization of M1 and M2 nanoemulsions using dynamic light scattering. (a) Representative size and (b) zeta potential distribution of M1 (black) and M2 (red) nanoemulsions. (c) Long term storage stability of M2 nanoemulsion and (d) M1 nanoemulsion at 4, 25 and 37 °C assessed by droplet size measurements. The error bars in panels C and D represent half width of polydispersity index (PDIw/2).
Mentions: Droplet size and zeta potential showed mono-modal distribution (Figure 5(a,b)) indicating the absence of large and small droplets. The average droplet size and PDI were around 180 and 0.2 for nanoemulsion M1 while nanoemulsion M2 showed a reduced droplet size and PDI around 130 nm and 0.15 respectively (Figure 5(a,c)). This reduced droplet size of C8-PFTE nanoemulsion (M2) is consistent with the sonicated nanoemulsions. Average zeta potential values for nanoemulsions M1 and M2 were negative, −5 to −7 mV (Figure 5(b)). For stable colloidal preparations, large zeta potential values (>±30 mV) are preferred to ensure repulsion between the droplets [31]. However, this requirement is not necessary for nanoemulsions prepared with Pluronic® nonionic surfactants. Pluronics provide stabilization via steric hindrance rather than charge repulsion and the observed zeta potential values are consistent with earlier reported values [8]. Storage stability was evaluated at 4, 25 and 37 °C by analyzing nanoemulsion samples at regular time intervals using DLS. Both formulations were shown to be stable for at least 160 days at all temperatures tested (Figure 5(c,d)).

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