Spinal cord injury (SCI) is a traumatic injury to the spinal cord which is not a consequence of the disease. Mesenchymal stem cells (MSCs) have gradually become one of the most used stem cells in research and clinic trial. Based on the previous reports employed the cells ranged from 4 • 105 to 1 • 106, the present study was performed to figure out the best number of MSCs for transplantation of the chronic SCI. Magnetic nanoparticles were used for proving the precise transplantation strategy. Using magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), diffusion tensor tractography (DTT), and behavior testing evaluations, we focused the effect of varying numbers of MSCs on reducing lesion cavity and post–traumatic syrinx formation, suppressing glial scar formation, enhancing neuronal fibers remodeling, promoting axonal regeneration and sprouting, improving vascularization, ameliorating the neuronal factors expressional level, and function improvement. Magnetic nanoparticles were precisely transplanted into the post–traumatic syrinx (PTS). MSCs can restore function after chronic SCI through stimulating the regeneration and sprouting of the axons, reducing the formation of PTS. The effect of MSCs on PTS management and functional improvement post chronic SCI was cell number–dependent, and within the range of 4 • 105 to 1 • 106, 1 • 106 cells were proved to be the best dose.
VIEWS 4410
Targeted delivery of antisense drugs is a promising technology which can provide a platform for the development of highly effective therapeuticals against a broad range of diseases. Insufficient stability of RNA in biological media coupled with hydrophilicity that prevents the molecule from penetrating cell membranes considerably limit RNA application in clinical practice. The aim of this work was to design a system for antisense drug delivery to liver hepatocytes using lipidoid magnetic nanoparticles (LNP). Nanocubes (NC) with average sizes of 16 and 27 nm were synthesized through decomposition of iron (III) oleate under high temperature conditions and functionalized with a cationic lipidoid С12-200. Magnetic NC demonstrated good MR-contrasting properties. Biodistribution of LNP was studied in vivo in BALB/c mice using the MR scanner. Additionally, liver sections obtained from the mice were subjected to histological examination. Nanoparticles of smaller size did not have a cytotoxic effect on HepG2 and Huh7 cell lines, whereas for larger NC, IC50 was 21.5 μg/ml and 126 μg/ml for HepG2 and Huh7 cells, respectively. Smaller particles tended to accumulate in hepatocytes. Bigger NC mainly accumulated in the spleen but also ended up in liver macrophages. This fact can be explained by a bigger hydrodynamic size of nanoparticles with a bigger magnetic core. Particles with smaller cores are a more effective platform for the delivery of antisense drugs to hepatocytes.
VIEWS 4640
Aluminum phthalocyanine nanoparticles (NP AlPc) possess the features that make them a promising photosensitizer. In particular, AlPc NPs do not fluoresce in free nanoform, fluoresce weakly in normal tissue, strongly in tumors and very strongly in macrophages. Also, such particles fluoresce and become phototoxic when contacting certain biocomponents. The type of biocomponents that bind to AlPc NPS defines intensity, lifetime, and spectral distribution of the fluorescence. This study aimed to investigate the peculiarities of nanophotosensitizer capturing in 3D models of cell cultures. The data obtained demonstrate that AlPc NPs are captured by cells inside the spheroid in the course of the first hour, as the fluorescent signal's growth shows. Having analyzed the fluctuations of the fluorescence signal of AlPc NPs inside a spheroid, we have also discovered that the cellular 3D models are heterogeneous. Laser irradiation (two-photon excitation at λ = 780/390 nm) resulted in photobleaching of fluorescence, which is probably associated with AlPc NP deactivation. Thus, the created model comprised of a 3D cell culture and AlPc NPs provides a better insight into metabolic processes in cells than monolayer 2D cell cultures. Besides, the model allows to evaluate the photodynamic effect depending on phenotypic properties of various areas in the heterogeneous 3D-structure.
VIEWS 4522