Preferential Accumulation Of Nanoparticles Research Articles

Selectively Tracking Nanoparticles in Aquatic Plant Using Core-Shell Nanoparticle-Enhanced Raman Spectroscopy Imaging.

Nanoparticles contribute to enormous environmental processes, but, due to analytical challenges, the understanding of nanoparticle fate remains elusive in complex environmental matrices. To address the challenge, a core-shell nanoparticle-enhanced Raman spectroscopy (CSNERS) imaging method was developed to selectively track prevalent SiO2 nanoparticles in an aquatic plant, Lemna minor. By encapsulating gold nanoparticles and Raman reporters inside, the resonance Raman signature was enhanced, thus enabling the sensitive and selective detection of SiO2 nanoparticles at an environmentally relevant concentration. The panoramic visualization of the translocation pathway of nanoparticles shows an unexpected, fast (in hours) and a preferential accumulation of nanoparticles on the node, leaf edge, root cap, etc., implying the ability of CSNERS to spectroscopically determine nanotoxicity. The core-shell design in CSNERS was capable of multiplex labeling two differently charged nanoparticles and distinguishing their biobehavior simultaneously. Meanwhile, the CSNERS method can be further applied for a variety of nanoparticles, implying its promising applications for nanotoxicity research and biogeochemical study.

Preferential Tumor Accumulation of Polyglycerol Functionalized Nanodiamond Conjugated with Cyanine Dye Leading to Near-Infrared Fluorescence In Vivo Tumor Imaging.

Preferential accumulation of nanoparticles in a tumor is realized commonly by combined effects of active and passive targeting. However, passive targeting based on an enhanced permeation and retention (EPR) effect is not sufficient to observe clear tumor fluorescence images in most of the in vivo experiments using tumor-bearing mice. Herein, polyglycerol-functionalized nanodiamonds (ND-PG) conjugated with cyanine dye (Cy7) are synthesized and it is found that the resulting ND-PG-Cy7 is preferentially accumulated in the tumor, giving clear fluorescence in in vivo and ex vivo fluorescence images. One of the plausible reasons is the longer in vivo blood circulation time of ND-PG-Cy7 (half-life: 58 h determined by the pharmacokinetic analysis) than that of other nanoparticles (half-life: <20 h in most of the previous reports). In a typical example, the fluorescence intensity of tumors increases due to continuous tumor accumulation of ND-PG-Cy7, even more than one week postinjection. This may be owing to the stealth effect of PG that was reported previously, avoiding recognition and excretion by reticuloendothelial cells, which are abundant in liver and spleen. In fact, the fluorescence intensities from the liver and spleen is similar to those from other organs, while the tumor exhibits much stronger fluorescence in the ex vivo image.

Direct observation of nanoparticle migration in epoxy based fiber reinforced composites using fluorescence microscopy

The preferential accumulation of nanoparticles at carbon fiber surfaces, induced by the addition of a thermoplastic “migrating agent” to an epoxy resin, was monitored via in situ fluorescence microscopy. (3-Glydidyloxypropyl)trimethoxysilane functionalized fluorescent silica nanoparticles (GFCSP) were synthesized by a modified Stöber method to track the spatiotemporal abundance of nanoparticles. Single carbon fibers were embedded in an uncured epoxy mixture consisting of tetraglycidyl-4,4-diaminodiphenylmethane and 4,4’-diamnodiphenyl sulfone, as well as thermoplastic migrating agent, poly(ether sulfone), and GFCSP. A heated microscope stage was used to monitor the fluorescence in the local vicinity of the fiber as the epoxy begins to cross-link and solidify upon heating. Our results show that the synthesized GFCSP accumulate at fiber surfaces only in the presence of poly(ether sulfone), as verified using scanning electron micrographs of Mode I fiber fracture surfaces.

Formulating Paclitaxel in Nanoparticles Alters Its Disposition

Paclitaxel is active and widely used to treat multiple types of solid tumors. The commercially available paclitaxel formulation uses Cremophor/ethanol (C/E) as the solubilizers. Other formulations including nanoparticles have been introduced. This study evaluated the effects of nanoparticle formulation of paclitaxel on its tissue distribution. We compared the plasma and tissue pharmacokinetics of paclitaxel-loaded gelatin nanoparticles and the C/E formulation. Mice were given paclitaxel-equivalent doses of 10 mg/kg by intravenous injection. The nanoparticle and C/E formulations showed significant differences in paclitaxel disposition; the nanoparticles yielded 40% smaller area under the blood concentration-time curve and faster blood clearance of total paclitaxel concentrations (sum of free, protein-bound, and nanoparticle-entrapped drug). The two formulations also showed different tissue specificity. The rank order of tissue-to-blood concentration ratios was liver > small intestine > kidney >> large intestine > spleen = stomach > lung > heart for the nanoparticles, and liver > small intestine > large intestine > stomach > lung > or = kidney > spleen > heart for the C/E formulation. The nanoparticles also showed longer retention and higher accumulation in organs and tissues (average of 3.2 +/- 2.3-fold), especially in the liver, small intestine, and kidney. The most striking difference was an 8-fold greater drug accumulation and sustained retention in the kidney. These data indicate that formulation of paclitaxel affects its clearance and distribution into tissues, with preferential accumulation of nanoparticles in the liver, spleen, small intestine, and kidney.