Novel functionalized nanoparticles, with toxicity controlled by laser irradiation, are perspective agents for potential (MRI)-guided stimulated chemo-photothermal treatment of cancer.
The
aim of our study was to develop a novel method for nanocarriers’
preparation as a fluorine magnetic resonance imaging (
19
F MRI)-detectable drug delivery system. The novelty of the proposed
approach is based on the application of fluorinated polyelectrolyte
Nafion as a contrast agent since typical MRI contrast agents are based
on paramagnetic gadolinium or ferro/superparamagnetic iron oxide compounds.
An advantage of using an
19
F-based tracer comes from the
fact that the
19
F image is detected at a different resonance
frequency than the
1
H image. In addition, the close to
zero natural concentration of
19
F nuclei in the human body
makes fluorine atoms a promising MRI marker without any natural background
signal. That creates the opportunity to localize and identify only
exogenous fluorinated compounds with 100% specificity. The nanocarriers
were formed by the deposition of polyelectrolytes on nanoemulsion
droplets via the layer-by-layer technique with the saturation approach.
The polyelectrolyte multilayer shell was composed of Nafion, the fluorinated
ionic polymer used for labeling by
19
F nuclei, and poly-
l
-lysine (PLL). The surface of such prepared nanocarriers was
further pegylated by adsorption of pegylated polyanion, poly-
l
-glutamic acid (PGA). The
19
F MRI-detectable hydrophobic
nanocarriers with an average size of 170 nm and a sufficient signal-to-noise
ratio have been developed and optimized to be used for passive tumor
targeting and drug delivery.
The application of the Three-Dimensional Ultra-Short Echo Time (3D UTE) pulse sequence at a high magnetic field for visualization of the distribution of 19F loaded theranostic core-shell nanocapsules with Nafion® (1,1,2,2-tetrafluoroethene; 1,1,2,2-tetrafluoro-2- [1,1,1,2,3,3-hexafluoro-3-(1,2,2-trifluoroethenoxy)propan-2-yl] oxyethanesulfonic acid) incorporated into the shell is presented. The nanocarriers were formed via the layer-by-layer technique with biodegradable polyelectrolytes: PLL (Poly-L-lysine), and with Nafion®: polymer with high 19F content. Before imaging, an MR (magnetic resonance) spectroscopy and T1 and T2 measurements were performed, resulting in values of T2 between 1.3 ms and 3.0 ms, depending on the spectral line. To overcome limitations due to such short T2, the 3D UTE pulse sequence was applied for 19F MR imaging. First Nafion® solutions of various concentrations were measured to check the detection limit of our system for the investigated molecule. Next, the imaging of a phantom containing core-shell nanocapsules was performed to assess the possibility of visualizing their distribution in the samples. Images of Nafion® containing samples with SNR ≥ 5 with acquisition time below 30 minutes for 19F concentration as low as 1.53·10−2 mmol 19F/g of sample, were obtained. This is comparable with the results obtained for molecules, which exhibit more preferable MR characteristics.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.