Liposomes are used in commercial pharmaceutical formulations (PFs) and dietary supplements (DSs) as a carrier vehicle to protect the active ingredient from degradation and to increase the half-life of the injectable. Even as the commercialization of liposomal products has rapidly increased, characterization methodologies to evaluate physical and chemical properties of the liposomal products have not been well-established. Herein we develop rapid methodologies to evaluate chemical and selected physical properties of liposomal formulations. Chemical properties of liposomes are determined by their lipid composition. The lipid composition is evaluated by first screening of the lipids present in the sample using HPLC-ELSD followed by HPLC-MSMS analysis with high mass accuracy (< 5 ppm), fragmentation pattern and lipid structure databases searching. Physical properties such as particle size and size distribution were investigated using Tunable Resistive Pulse Sensing (TRPS). The developed methods were used to analyze commercially available PFs and DSs. As results, PFs contain distinct number of lipids as indicated by the manufacture, but DSs were more complicated containing a large number of lipids belonging to different sub-classes. Commercially available liposomes have particles with wide size distribution based on size measurements performed by TRPS. The high mass accuracy as well as identification lipids using multiple fragment ions aided to accurately identify the lipids and differentiate them from other lipophilic molecules. The developed analytical methodologies were successfully adapted to measure the physiochemical properties of commercial liposomes.

Nanomaterials are beginning to enter our daily lives through various consumer products as the result of technology commercialization. The development of methodologies to detect the presence of nanomaterials in consumer products is an essential element in understanding our exposure. In this study, we have developed methods for the separation and characterization of silicon dioxide (SiO2) and titanium dioxide (TiO2) nanostructures in dietary supplements marketed in products specifically targeted for women. A total of 12 commercial products claiming the inclusion of SiO2 and TiO2, but not making any claims regarding the particle size, were randomly selected for purchase through various retailers. To isolate nanostructures from these products, a simple methodology that combines acid digestion and centrifugation was utilized. Once isolated, the chemical composition, size, morphology, and crystal structure were characterized using mass spectroscopy, light scattering, electron microscopy, and X-ray diffraction techniques. SiO2 and TiO2 nanostructures were detected in 11 of 12 products using these methods. Many of the isolated nanoscale materials showed a high degree of aggregation; however, identified individual structures had at least one dimension below 100 nm. These robust methods can be used for routine monitoring of commercial products for nanoscale oxides of silica and titanium.

Journal Article Cryo Transmission Electron Microscopy of Three Research-Grade Liposomal Formulations of Doxorubicin Get access William Monroe, William Monroe U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA Search for other works by this author on: Oxford Academic Google Scholar Angel Paredes, Angel Paredes U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA Search for other works by this author on: Oxford Academic Google Scholar Patrick Sisco, Patrick Sisco U.S. Food and Drug Administration, Office of Regulatory Affairs, Jefferson, Arkansas, USA Search for other works by this author on: Oxford Academic Google Scholar Kristen Ahlschwede, Kristen Ahlschwede U.S. Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas, USA Search for other works by this author on: Oxford Academic Google Scholar Sean Linder Sean Linder U.S. Food and Drug Administration, Office of Regulatory Affairs, Jefferson, Arkansas, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 927–928, https://doi.org/10.1017/S1431927615005437 Published: 23 September 2015

Due to the increasing use of engineered nanomaterials in consumer products, regulatory agencies and other research organizations have determined that the development of robust, reliable, and accurate methodologies to characterize nanoparticles in complex matrices is a top priority. Of particular interest are methods that can separate and determine the size of nanomaterials in samples that contain polydisperse and/or multimodal nanoparticle populations. Asymmetric-flow field flow fractionation (AF4) has shown promise for the separation of nanoparticles with wide size range distributions; however, low analyte recoveries and decreased membrane lifetimes, due to membrane fouling, have limited its application. Herein, we report straightforward strategies to minimize membrane fouling and improve nanoparticle recovery by functionalizing the surface of the nanoparticles, as well as that of the AF4 membranes. Gold nanoparticles (AuNP) were stabilized through functionalization with a phosphine molecule, whereas the surface of the membranes was coated with a negatively charged polystyrenesulfonate polymer. Improved nanoparticle separation, recoveries of 99.1 (±0.5) %, and a detection limit of 6 μg/kg were demonstrated by analyzing AuNP reference materials of different sizes (e.g., 10, 30, and 60 nm), obtained from the National Institute of Standards and Technology (NIST). Furthermore, the stability of the polymer coating and its specificity toward minimizing membrane fouling were demonstrated.

Cell behavior in the presence of nanomaterials is typically explored through simple viability assays, but there is mounting evidence that nanomaterials can have more subtle effects on a variety of cellular functions. Previously our lab demonstrated that gold nanorods functionalized with polyelectrolyte multi-layers inhibited rat cardiac fibroblast-mediated remodeling of type I collagen scaffolds by altering fibroblast phenotype and the mechanical properties of the collagen network. In this work, we examine a possible mechanism for these effects: adsorption of cellular proteins by the nanorods. Mass spectrometric and gel electrophoresis of media collected from cultured cells suggests that a number of proteins, some of which mediate cell-cell and cell-matrix interactions, adsorb onto the surface of these nanoparticles in vitro. Polyethylene glycol coating of the nanorods largely mitigates protein adsorption and fibroblast-mediated collagen remodeling. These results suggest that adsorption of proteins by nanorods could have a significant effect on cell functions, including fibroblast-mediated matrix remodeling.

Gold nanoparticles are receiving considerable attention due to their novel properties and the potential variety of their uses. Long gold nanorods with dimensions of approximately 20 × 400 nm exhibit strong light scattering and can be easily observed under dark-field microscopy. Here we describe the use of this light-scattering property to track micrometer scale strains in collagen gels and thick films, which result from cell traction forces applied by neonatal heart fibroblasts. The use of such collagen constructs to model cell behavior in the extracellular matrix is common, and describing local mechanical environments on such a small scale is necessary to understand the complex factors associated with the remodeling of the collagen network. Unlike other particles used for tracking purposes, gold nanorods do not photobleach, allowing their optical signal to be tracked for longer periods of time, and they can be easily synthesized and coated with various charged or neutral shells, potentially reducing the effect of their presence on the cell system or allowing selective placement. Techniques described here are ultimately applicable for investigations with a wide variety of cells and cell environments.

This work reports the distribution of negatively charged, gold core nanoparticles in a model marine estuary as a function of time. A single dose of purified polystyrene sulfonate (PSS)-coated gold nanorods was added to a series of three replicate estuarine mesocosms to emulate an abrupt nanoparticle release event to a tidal creek of a Spartina-dominated estuary. The mesocosms contained several phases that were monitored: seawater, natural sediments, mature cordgrass, juvenile northern quahog clam, mud snails, and grass shrimp. Aqueous nanorod concentrations rose rapidly upon initial dosing and then fell to stable levels over the course of approximately 50 h, after which they remained stable for the remainder of the experiment (41 days total). The concentration of nanorods rose in all other phases during the initial phase of the experiment; however, some organisms demonstrated depuration over extended periods of time (100+ h) before removal from the dosed tanks. Clams and biofilm samples were also removed from the contaminated tanks post-exposure to monitor their depuration in pristine seawater. The highest net uptake of gold (mass normalized) occurred in the biofilm phase during the first 24 h, after which it was stable (to the 95% level of confidence) throughout the remainder of the exposure experiment. The results are compared against a previous study of positively charged nanoparticles of the same size to parameterize the role of surface charge in determining nanoparticle fate in complex aquatic environments.

We report the direct visualization of interactions between drug-loaded nanoparticles and the cancer cell nucleus. Nanoconstructs composed of nucleolin-specific aptamers and gold nanostars were actively transported to the nucleus and induced major changes to the nuclear phenotype via nuclear envelope invaginations near the site of the construct. The number of local deformations could be increased by ultrafast, light-triggered release of the aptamers from the surface of the gold nanostars. Cancer cells with more nuclear envelope folding showed increased caspase 3 and 7 activity (apoptosis) as well as decreased cell viability. This newly revealed correlation between drug-induced changes in nuclear phenotype and increased therapeutic efficacy could provide new insight for nuclear-targeted cancer therapy.

Nuclear-targeted therapy has received increasing attention as a potential strategy to improve the therapeutic efficacy of treating cancer. The main challenges include targeting, drug-delivery efficiency and release of anticancer agents to the cancer cell nucleus. Nanoparticles as nanocarriers have started to address some of these issues. However, a lack of understanding in how nanoconstructs interact with the nucleus has precluded detailed studies. In this article, we highlight a nanoconstruct composed of gold (Au) nanostars loaded with nucleolin-specific aptamers. This nanoconstruct induced major changes in the nuclear phenotype through nuclear envelope (NE) invaginations. Femtosecond, light-triggered release of the aptamers from the surface of the Au nanostars further increased the number of NE deformations. Cancer cells with more NE folding showed increased apoptosis as well as decreased cell viability. The author's of this article have revealed that correlation between drug-induced changes in nuclear phenotypes and increased therapeutic efficacy can provide new insight into nuclear-targeted cancer therapy.

Gold nanorods have promising applications in the fields of drug delivery and photothermal therapy. These promises arise from the nanorods' unique optical and photothermal properties, the availability of synthetic protocols that can tune the size and shape of the particles, the ability to modify the surface and conjugate drugs/molecules to the nanorods, and the relative biocompatibility of gold nanorods. In this review, current progress in using gold nanorods as phototherapeutic agents and as drug delivery vehicles is summarized. Issues of dosage, toxicity and biological interactions at three levels (biological media alone; cells; whole organisms) are discussed, concluding with recommendations for future work in this area.

The potential of gold nanorods to act as “antennae” in organic photovoltaic devices and improve performance by enhancing the optical field within the device has been examined. Gold nanorods were blended into the buffer layer of standard poly (3-hexothiopene) (P3HT): 6, 6-phenyl C61-butyric acid methyl ester (PCBM) photovoltaic cells. Increases in both the broad spectrum absorption and device fill factors (as compared to solar cells without nanorods) were observed. A comparison of the internal resistance and absorption allows estimation of what part in the change in performance can be attributed to greater absorption and increases in buffer layer conductivity.

Gold nanorods have received tremendous attention in recent years due to their exciting potential applications in chemical sensing, biological imaging, drug delivery and phototherapeutics. A seed-mediated growth procedure in aqueous solution has been developed to produce these colloidal materials in reasonable quantities, with tunable shape. Details of the reaction chemistry, role of impurity ions, and their influence on the final product shape are still under debate. Subsequent chemistry on preformed nanorods can yield a variety of new shapes and functionalities for numerous applications.

Gold nanorods exhibit optical properties that are turnable with their shape, leading to sensing, imaging, and bipmedical therapeutic applications. Colloidal preparations of gold nanorods impart surfactants or other species on the nanorod surfaces; a popular preparation leads to a surfactant bilayer on the surface. The specific chemistry at three distinct interfaces has roles to play in the growth and subsequent usage of these nanomaterials; these interfaces are the gold-surfactant interface, the hydrophobic surfactant bilayer, and, finally, the surfactant interface with the aqueous bulk. Each one of these interfaces provides strategies for altering nanorod properties such as stability against aggregation, toxicity and ease of assembly. It is the solvent-accessible interface that dictates nanorod interactions with other particles, macromolecules, and living cells.

The optical field intensity of light scattering from nanorods of gold has been imaged at distances that are intermediate between the near-field and far-field regimes using a near-field scanning optical microscope (NSOM). For scattering from isolated nanorods the Fraunhofer diffractive behaviour is modified slightly by the dipolar nature of metal nanoantannae as would be expected at these imaging distances. However, when the nanorods are brought into close proximity, interactions between the nanorods alter the scattering behaviour substantially creating large field intensities between the structures. By sampling the field with the near-field microscope tip scanned at different heights, detailed maps of the scattering profile can be generated.[GRAPHICS]The NSOM image of far-field scattered light from an isolated gold nanorod. The nanorod was imaged at a distance of roughly 8 mu m above the support substrate using a scanning near-field microscope operated at constant height mode. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Gold nanorods (AuNRs) have unique optical properties for numerous biomedical applications, but the interactions between AuNRs and proteins, particularly those of the extracellular matrix (ECM), are poorly understood. Here the effects of AuNRs on the self-assembly, mechanics, and remodeling of type I collagen gels were examined in vitro. AuNRs were modified with polyelectrolyte multilayers (PEMs) to minimize cytotoxicity, and AuNRs with different terminal polymer chemistries were examined for their interactions with collagen by turbidity assays, rheological tests, and microscopy. Gel contraction assays were used to examine the effects of the PEM-coated AuNRs on cell-mediated collagen remodeling. Polyanion-terminated AuNRs significantly reduced the lag (nucleation) phase of collagen self-assembly and significantly increased the dynamic shear modulus of the polymerized gels, whereas polycation-terminated AuNRs had no effect on the mechanical properties of the collagen. Both polyanion- and polycation-terminated AuNRs significantly inhibited collagen gel contraction by cardiac fibroblasts, and the nanoparticles were localized in intra-, peri-, and extracellular compartments, suggesting that PEM-coated AuNRs influence cell behavior via multiple mechanisms. These results demonstrate the significance of nanoparticle–ECM interactions in determining the bioactivity of nanoparticles.