Intracellular accumulation and dissolution of silver nanoparticles in L-929 fibroblast cells using live cell time-lapse microscopy.

Cytotoxicity assessments of nanomaterials, such as silver nanoparticles, are challenging due to interferences with test reagents and indicators as well uncertainties in dosing as a result of the complex nature of nanoparticle intracellular accumulation. Furthermore, current theories suggest that silver nanoparticle cytotoxicity is a result of silver nanoparticle dissolution and subsequent ion release. This study introduces a novel technique, nanoparticle associated cytotoxicity microscopy analysis (NACMA), which combines fluorescence microscopy detection using ethidium homodimer-1, a cell permeability marker that binds to DNA after a cell membrane is compromised (a classical dead-cell indicator dye), with live cell time-lapse microscopy and image analysis to simultaneously investigate silver nanoparticle accumulation and cytotoxicity in L-929 fibroblast cells.

The effect of shear flow on nanoparticle agglomeration and deposition in in vitro dynamic flow models.

Traditional in vitro toxicity experiments typically involve exposure of a mono- or co-culture of cells to nanoparticles (NPs) in static conditions with the assumption of 100% deposition (i.e. dose) of well-dispersed particles.

Slow release of ions from internalized silver nanoparticles modifies the epidermal growth factor signaling response.

Due to their distinctive physiochemical properties, including a robust antibacterial activity and plasmonic capability, hundreds of consumer and medical products contain colloidal silver nanoparticles (AgNPs). However, even at sub-toxic dosages, AgNPs are able to disrupt cell functionality, through a yet unknown mechanism. Moreover, internalized AgNPs have the potential to prolong this disruption, even after the removal of excess particles.

Less is more: long-term in vitro exposure to low levels of silver nanoparticles provides new insights for nanomaterial evaluation.

In view of the vast number of new nanomaterials (NMs) that require testing and the constraints associated with animal models, the majority of studies to elucidate nanotoxicological effects have occurred in vitro, with limited correlation and applicability to in vivo systems and realistic, occupational exposure scenarios. In this study, we developed and implemented a chronic in vitro model coupled with lower, regulatory dosages in order to provide a more realistic assessment of NM-dependent consequences and illuminate the implications of long-term NM exposure. When keratinocytes were exposed to 50 nm silver nanoparticles (Ag-NPs), we determined that chronically dosed cells operated under augmented stress and modified functionality in comparison to their acute counterparts.

Tannic acid coated gold nanorods demonstrate a distinctive form of endosomal uptake and unique distribution within cells.

One of the primary challenges associated with nanoparticle-dependent biological applications is that endosomal entrapment in a physiological environment severely limits the desired targeting and functionality of the nanoconstructs. This study sought to overcome that challenge through a systematic approach of gold nanorod (GNR) functionalization: evaluating the influence of both aspect ratio and surface chemistry on targeted cellular internalization rates and preservation of particle integrity. Owing to their unique spectral properties and enhanced surface area, GNRs possess great potential for the advancement of nanobased delivery and imaging applications.

Systematic analysis of silver nanoparticle ionic dissolution by tangential flow filtration: toxicological implications.

In the field of toxicology of nanomaterials, scientists have not clearly determined if the observed toxicological events are due to the nanoparticles (NPs) themselves or the dissolution of ions released into the biophysiological environment or both phenomenon participate in combination based upon their bioregional and temporal occurrence during exposure conditions. Consequently, research involving the toxicological analysis of silver NPs (Ag-NPs) has shifted towards assessment of 'nanosized' silver in comparison to its solvated 'ionic' counterpart. Current literature suggests that dissolution of ions from Ag-NPs may play a key role in toxicity; however, the present assessment methodology to separate ions from NPs still requires improvement before a definitive cause of toxicity can be determined.

The biological impact of concurrent exposure to metallic nanoparticles and a static magnetic field.

The rapid advancement of technology has led to an exponential increase of both nanomaterial and magnetic field utilization in applications spanning a variety of sectors. While extensive work has focused on the impact of these two variables on biological systems independently, the existence of any synergistic effects following concurrent exposure has yet to be investigated. This study sought to ascertain the induced alterations to the stress and proliferation responses of the human adult low calcium, high temperature keratinocyte (HaCaT) cell line by the application of a static magnetic field (approximately 0.

Gold nanoparticles induce transcriptional activity of NF-κB in a B-lymphocyte cell line.

Gold nanoparticles (Au-NPs) have been designated as superior tools for biological applications owing to their characteristic surface plasmon absorption/scattering and amperometric (electron transfer) properties, in conjunction with low or no immediate toxicity towards biological systems. Many studies have shown the ease of designing application-based tools using Au-NPs but the interaction of this nanosized material with biomolecules in a physiological environment is an area requiring deeper investigation. Immune cells such as lymphocytes circulate through the blood and lymph and therefore are likely cellular components to come in contact with Au-NPs.

Novel platform development using an assembly of carbon nanotube, nanogold and immobilized RNA capture element towards rapid, selective sensing of bacteria.

This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleiuc acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles.

Does shape matter? Bioeffects of gold nanomaterials in a human skin cell model.

Gold nanomaterials (AuNMs) have distinctive electronic and optical properties, making them ideal candidates for biological, medical, and defense applications. Therefore, it is imperative to evaluate the potential biological impact of AuNMs before employing them in any application. This study investigates two AuNMs with different aspect ratios (AR) on mediation of biological responses in the human keratinocyte cell line (HaCaT) to model potential skin exposure to these AuNMs.

Interference of silver, gold, and iron oxide nanoparticles on epidermal growth factor signal transduction in epithelial cells.

Metallic nanomaterials, including silver, gold, and iron oxide, are being utilized in an increasing number of fields and specialties. The use of nanosilver as an antimicrobial agent is becoming ever-more common, whereas gold and iron oxide nanomaterials are frequently utilized in the medical field due to their recognized "biocompatibility". Numerous reports have examined the general toxicity of these nanomaterials; however, little data exists on how the introduction of these nanomaterials, at nontoxic levels, affects normal cellular processes.