Effects of iron oxide nanoparticles on biological responses and MR imaging properties in human mammary healthy and breast cancer epithelial cells.

Superparamagnetic iron oxide nanoparticles (SPIONs, diameters >50 nm) have received great attention due to their promising use as magnetic resonance imaging (MRI) contrast agents. In this study, we evaluated the cellular uptake and biological responses in vitro of ultrasmall SPIONs (USPIONs, diameters < 50 nm). We compared the cellular responses between breast epithelia isolated from healthy and breast cancer donors after exposure to carboxy-terminated USPIONs (10 and 30 nm PEG-coated, 10 and 30 nm non-PEG-coated). The particles were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and gel electrophoresis. Cellular interactions with USPIONs were assessed by confocal microscopy and TEM. Cellular uptake of USPIONs was quantified using ICP-MS. Cell viability was measured by MTT and neutral red uptake assays. T2* weighted MRI scans were performed using a 7T scanner. Results demonstrated that cell association/internalization of USPIONs was size- and surface coating-dependent (PEG vs. non-PEG), and higher cellular uptake of 10 and 30 nm non-coated particles was observed in both cell types compared with PEG-coated particles. Cell uptake for 10 and 30 nm non-coated particles was higher in cancer cells from two of three tested donors compared to healthy cells from three donors. There was no significant cytotoxicity observed for all tested particles. Significantly enhanced MRI contrast was observed following exposure to 10 and 30 nm non-coated particles compared to PEG-coated particles in both cell types. In comparison, cancer cells showed more enhanced MRI signals when compared to normal cells. The data indicate that cell responses following exposure to USPIONs are dependent on particle properties. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1032-1042, 2016.

Proteomic analysis of early response lymph node proteins in mice treated with titanium dioxide nanoparticles.

Human exposure to nanoparticles is inevitable from natural and anthropogenic sources. Titanium dioxide (TiO2) nanoparticles are increasingly being used in pharmaceutical and cosmetic products. Previous studies revealed that TiO2 levels were significantly increased in tissues (e.g., lymph nodes) after mice were injected with nanosized TiO2. To identify early response lymph node proteins to TiO2 nanoparticles, groups of mice were intradermally injected with a low dose of DeGussa P25 TiO2 nanoparticles or vehicle alone. The proteomes of lymph nodes at 24 h were quantitatively analyzed using trypsin-catalyzed 16O/18O labeling in conjunction with two-dimensional liquid chromatography separation and tandem mass spectrometry (2DLC-MS/MS). A total of 33 proteins were significantly changed (over 1.3-fold, p<0.05) in the mice treated with TiO2 nanoparticles, which accounted for approximately 1% of the total proteins identified. The differentially expressed proteins mainly involve the immune response (e.g., inflammation), lipid and fatty acid metabolism, mRNA processing, and nucleosome assembly. Regulation of functionally distinct classes of proteins could be mediated by estrogen receptor (ESR1), PPARγ, and c-Myc signalings, etc. The differentially expressed proteins identified in this experiment could represent early response proteins to TiO2 nanoparticle treatment in mouse lymph nodes.

Mechanistic toxicity evaluation of uncoated and PEGylated single-walled carbon nanotubes in neuronal PC12 cells.

We investigated and compared the concentration-dependent cytotoxicity of single-walled carbon nanotubes (SWCNTs) and SWCNTs functionalized with polyethylene glycol (SWCNT-PEGs) in neuronal PC12 cells at the biochemical, cellular, and gene expressional levels. SWCNTs elicited cytotoxicity in a concentration-dependent manner, and SWCNT-PEGs exhibited less cytotoxic potency than uncoated SWCNTs. Reactive oxygen species (ROS) were generated in both a concentration- and surface coating-dependent manner after exposure to these nanomaterials, indicating different oxidative stress mechanisms. More specifically, gene expression analysis showed that the genes involved in oxidoreductases and antioxidant activity, nucleic acid or lipid metabolism, and mitochondria dysfunction were highly represented. Interestingly, alteration of the genes is also surface coating-dependent with a good correlation with the biochemical data. These findings suggest that surface functionalization of SWCNTs decreases ROS-mediated toxicological response in vitro.

Quantitative determination of skin penetration of PEG-coated CdSe quantum dots in dermabraded but not intact SKH-1 hairless mouse skin.

Many cosmetics, sunscreens, and other consumer products are reported to contain nanoscale materials. The possible transdermal absorption of nanoscale materials and the long-term consequences of the absorption have not been determined. We used polyethylene glycol coated cadmium selenide (CdSe) core quantum dots (QD; 37 nm diameter) to evaluate the penetration of nanoscale material into intact, tape stripped, acetone treated, or dermabraded mouse skin. QD were suspended in an oil-in-water emulsion (approximately 9 microM) and the emulsion was applied at 2 mg/cm(2) to mouse dorsal skin pretreated as follows: intact; tape stripped to remove the stratum corneum; acetone pretreated; dermabraded to remove stratum corneum and epidermis. QD penetration into the skin was monitored in sentinel organs (liver and regional draining lymph nodes) using inductively coupled plasma mass spectrometry analysis of cadmium (from the CdSe QD). No consistent cadmium elevation was detected in the sentinel organs of mice with intact, acetone pretreated, or tape-stripped skin at 24- and 48-h post-QD application; however, in dermabraded mice, cadmium elevations were detected in the lymph nodes and liver. QD accumulation (as cadmium) in the liver was approximately 2.0% of the applied dose. The passing of QD through the dermabraded skin was confirmed using confocal fluorescence microscopy. These results suggest that transdermal absorption of nanoscale materials depends on skin barrier quality, and that the lack of an epidermis provided access to QD penetration. Future dermal risk assessments of nanoscale materials should consider key barrier aspects of skin and its overall physiologic integrity.