Cyto and genotoxicity of gold nanoparticles in human hepatocellular carcinoma and peripheral blood mononuclear cells

Long-Term Accumulation, Biological Effects and Toxicity of BSA-Coated Gold Nanoparticles in the Mouse Liver, Spleen, and Kidneys

Introduction

Gold nanoparticles are promising candidates as vehicles for drug delivery systems and could be developed into effective anticancer treatments. However, concerns about their safety need to be identified, addressed, and satisfactorily answered. Although gold nanoparticles are considered biocompatible and nontoxic, most of the toxicology evidence originates from in vitro studies, which may not reflect the responses in complex living organisms.

Methods

We used an animal model to study the long-term effects of 20 nm spherical AuNPs coated with bovine serum albumin. Mice received a 1 mg/kg single intravenous dose of nanoparticles, and the biodistribution and accumulation, as well as the organ changes caused by the nanoparticles, were characterized in the liver, spleen, and kidneys during 120 days.

Results

The amount of nanoparticles in the organs remained high at 120 days compared with day 1, showing a 39% reduction in the liver, a 53% increase in the spleen, and a 150% increase in the kidneys. The biological effects of chronic nanoparticle exposure were associated with early inflammatory and fibrotic responses in the organs and were more pronounced in the kidneys, despite a negligible amount of nanoparticles found in renal tissues.

Conclusion

Our data suggest, that although AuNPs belong to the safest nanomaterial platforms nowadays, due to their slow tissue elimination leading to long-term accumulation in the biological systems, they may induce toxic responses in the vital organs, and so understanding of their long-term biological impact is important to consider their potential therapeutic applications.

Gold Nanoparticles (AuNPs)-Toxicity, Safety and Green Synthesis: A Critical Review

In recent years, the extensive exploration of Gold Nanoparticles (AuNPs) has captivated the scientific community due to their versatile applications across various industries. With sizes typically ranging from 1 to 100 nm, AuNPs have emerged as promising entities for innovative technologies. This article comprehensively reviews recent advancements in AuNPs research, encompassing synthesis methodologies, diverse applications, and crucial insights into their toxicological profiles. Synthesis techniques for AuNPs span physical, chemical, and biological routes, focusing on eco-friendly "green synthesis" approaches. A critical examination of physical and chemical methods reveals their limitations, including high costs and the potential toxicity associated with using chemicals. Moreover, this article investigates the biosafety implications of AuNPs, shedding light on their potential toxic effects on cellular, tissue, and organ levels. By synthesizing key findings, this review underscores the pressing need for a thorough understanding of AuNPs toxicities, providing essential insights for safety assessment and advancing green toxicology principles.

Cellular Alterations Due to Direct and Indirect Interaction of Nanomaterials with Nucleic Acids

Deoxyribonucleic acid (DNA) represents the main reservoir of genetic information in the cells, which is why it is protected in the nucleus. Entry into the nucleus is, in general, difficult, as the nuclear membrane is a selective barrier to molecules longer than 40 kDa. However, in some cases, the size of certain nanoparticles (NPs) allows their internalization into the nucleus, thus causing a direct effect on the DNA structure. NPs can also induce indirect effects on DNA through reactive oxygen species (ROS) generation. In this context, nanomaterials are emerging as a disruptive tool for the development of novel therapies in a broad range of biomedical fields; although their effect on cell viability is commonly studied, further interactions with DNA or indirect alterations triggered by the internalization of these materials are not always clarified, since the small size of these materials makes them perfectly suitable for interaction with subcellular structures, such as the nucleus. In this context, and using as a reference the predicted interactions presented in a computational model, we describe and discuss the observed direct and indirect effects of the implicated nanomaterials on DNA.

Nanotechnology-based delivery systems to overcome drug resistance in cancer

Cancer nanomedicine is defined as the application of nanotechnology and nanomaterials for the formulation of cancer therapeutics that can overcome the impediments and restrictions of traditional chemotherapeutics. Multidrug resistance (MDR) in cancer cells can be defined as a decrease or abrogation in the efficacy of anticancer drugs that have different molecular structures and mechanisms of action and is one of the primary causes of therapeutic failure. There have been successes in the development of cancer nanomedicine to overcome MDR; however, relatively few of these formulations have been approved by the United States Food and Drug Administration for the treatment of cancer. This is primarily due to the paucity of knowledge about nanotechnology and the fundamental biology of cancer cells. Here, we discuss the advances, types of nanomedicines, and the challenges regarding the translation of in vitro to in vivo results and their relevance to effective therapies.

Hybrid AuNPs-3MPS-MTX nanosystem and its evaluation for treating cervical cancer and melanoma

This research presents an evaluation of a hybrid material based on gold nanoparticles (AuNPs), stabilized with the thiol 3-mercapto-propanesulfonate (3MPS) and loaded with the methotrexate drug (MTX). The AuNPs-3MPS-MTX nanosystem was tested for the treatment of cervical cancer and melanoma, using the B16-F10 melanoma and HeLa cell lines. The tests performed on cell cultures assessed the efficiency of the studied nanosystem on tumor cells, as well as its toxicology.

Assessment of the potential cerebellar toxicity of gold nanoparticles on the structure and function of adult male albino rats

BACKGROUND

The regular use of gold nanoparticles (Au-NPs) may increase the likelihood of human exposure to these nanoparticles (NPs) and raises concerns about toxicity.

AIM

This study investigated the short-term impact of exposure to Au-NPs on inducing cerebellar pathology in rats, and whether the dose or duration of exposure was more important.

METHODOLOGY

The study used two concentrations of Au-NPs (25 and 50 particles per million) and 18 rats were randomly assigned to three groups. Assessments of the animals were done via behavioral, gene expression, histological, and immunohistochemistry analyses.

RESULTS

Both concentrations of Au-NPs caused cerebellar pathology, as assessed through the investigation test battery. The Au-NPs50 group displayed more injury and decreased mobility compared with the control and the Au-NPs25 group. The Au-NPs25 group showed an increase in supported rearing and significant up-regulation of the Rgc32 gene compared with the control. The Trkb gene was insignificantly up-regulated in both Au-NPs groups compared with the control.

CONCLUSION

The study indicates that exposure to Au-NPs can cause cerebellar pathology in rats and that the toxicity is more dependent on dose than the duration of exposure. These findings have significant implications for the safe use of Au-NPs in various applications.

Role of Tunable Gold Nanostructures in Cancer Nanotheranostics: Implications on Synthesis, Toxicity, Clinical Applications and Their Associated Opportunities and Challenges

The existing diagnosis and treatment modalities have major limitations related to their precision and capability to understand several stages of disease development. A superior therapeutic system consists of a multifunctional approach in early diagnosis of the disease with a simultaneous progressive cure, using a precise medical approach towards complex treatment. These challenges can be addressed via nanotheranostics and explore suitable approaches to improve health care. Nanotechnology in combination with theranostics as an unconventional platform paved the way for developing novel strategies and modalities leading to diagnosis and therapy for complex disease conditions, ranging from acute to chronic levels. Among the metal nanoparticles, gold nanoparticles are being widely used for theranostics due to their inherent non-toxic nature and plasmonic properties. The unique optical and chemical properties of plasmonic metal nanoparticles along with theranostics have led to a promising era of plausible early detection of disease conditions, and they enable real-time monitoring with enhanced non-invasive or minimally invasive imaging of several ailments. This review aims to highlight the improvement and advancement brought to nanotheranostics by gold nanoparticles in the past decade. The clinical use of the metal nanoparticles in nanotheranostics is explained, along with the future perspectives on addressing the key applications related to diagnostics and therapeutics, respectively. The scope of gold nanoparticles and their realistic potential to design a sophisticated theranostic system is discussed in detail, along with their implications in clinical advancements which are the needs of the hour. The review concluded with the challenges, opportunities, and implications on translational potential of using gold nanoparticles in nanotheranostics.

CdSe magic-sized quantum dots attenuate reactive oxygen species generated by neutrophils and macrophages with implications in experimental arthritis

The biological applicability of nanomaterials has been limited due to cytotoxicity. Studies have described the effects of nanomaterials on different tissues and cell types, but their actions on immune cells are less elucidated. This study describes unprecedented in vitro and in vivo antioxidant activities of cadmium selenide magic-sized quantum dots (CdSe MSQDs) with implications on rheumatoid arthritis. While the generation of ROS induced by nanomaterials is linked to cytotoxicity, we found that CdSe MSQDs reduced ROS production by neutrophils and macrophages following opsonized-zymosan stimuli, and we did not find cytotoxic effects. Interestingly, inherent antioxidant properties of CdSe MSQDs were confirmed through DPPH, FRAP, and ORAC assays. Furthermore, CdSe MSQDs reduced ROS levels generated by infiltrating leukocytes into joints in experimental model of rheumatoid arthritis. Briefly, we describe a novel application of CdSe MSQDs in modulating the inflammatory response in experimental rheumatoid arthritis through an unexpected antioxidant activity.

Evaluating nanobiomaterial-induced DNA strand breaks using the alkaline comet assay

Due to their unique chemical and physical properties, nanobiomaterials (NBMs) are extensively studied for applications in medicine and drug delivery. Despite these exciting properties, their small sizes also make them susceptible to toxicity. Whilst nanomaterial immunotoxicity and cytotoxicity are studied in great depth, there is still limited data on their potential genotoxicity or ability to cause DNA damage. In the past years, new medical device regulations, which came into place in 2020, were developed, which require the assessment of long-term NBM exposure; therefore, in recent years, increased attention is being paid to genotoxicity screening of these materials. In this article, and through an interlaboratory comparison (ILC) study conducted within the Horizon 2020 REFINE project, we assess five different NBM formulations, each with different uses, namely, a bio-persistent gold nanoparticle (AuNP), an IR-780 dye-loaded liposome which is used in deep tissue imaging (LipImage™815), an unloaded PACA polymeric nanoparticle used as a drug delivery system (PACA), and two loaded PACA NBMs, i.e. the cabazitaxel drug-loaded PACA (CBZ-PACA) and the NR668 dye-loaded PACA (NR668 PACA) for their potential to cause DNA strand breaks using the alkaline comet assay and discuss the current state of genotoxicity testing for nanomaterials. We have found through our interlaboratory comparison that the alkaline comet assay can be suitably applied to the pre-clinical assessment of NBMs, as a reproducible and repeatable methodology for assessing NBM-induced DNA damage.

Green Synthesis of Gold Nanoparticles Using Plant Extracts as Beneficial Prospect for Cancer Theranostics

Gold nanoparticles (AuNPs) have been widely explored and are well-known for their medical applications. Chemical and physical synthesis methods are a way to make AuNPs. In any case, the hunt for other more ecologically friendly and cost-effective large-scale technologies, such as environmentally friendly biological processes known as green synthesis, has been gaining interest by worldwide researchers. The international focus on green nanotechnology research has resulted in various nanomaterials being used in environmentally and physiologically acceptable applications. Several advantages over conventional physical and chemical synthesis (simple, one-step approach to synthesize, cost-effectiveness, energy efficiency, and biocompatibility) have drawn scientists’ attention to exploring the green synthesis of AuNPs by exploiting plants’ secondary metabolites. Biogenic approaches, mainly the plant-based synthesis of metal nanoparticles, have been chosen as the ideal strategy due to their environmental and in vivo safety, as well as their ease of synthesis. In this review, we reviewed the use of green synthesized AuNPs in the treatment of cancer by utilizing phytochemicals found in plant extracts. This article reviews plant-based methods for producing AuNPs, characterization methods of synthesized AuNPs, and discusses their physiochemical properties. This study also discusses recent breakthroughs and achievements in using green synthesized AuNPs in cancer treatment and different mechanisms of action, such as reactive oxygen species (ROS), mediated mitochondrial dysfunction and caspase activation, leading to apoptosis, etc., for their anticancer and cytotoxic effects. Understanding the mechanisms underlying AuNPs therapeutic efficacy will aid in developing personalized medicines and treatments for cancer as a potential cancer therapeutic strategy.

Liver Cancer: New Insights into Surgical and Nonsurgical Treatments

Introduction:

Hepatocellular carcinoma (HCC) is the most common type of liver cancer that has increased in recent years worldwide. Primary liver cancer or HCC is considered the 5th and 7th most common cancer among men and women, respectively. It is also the second leading cause of cancer death worldwide. Unfortunately, HCC is frequently diagnosed at an advanced stage when the majority of the patients do not have access to remedial therapies. Furthermore, current systemic chemotherapy shows low efficacy and minimum survival benefits. Liver cancer therapy is a multidisciplinary, multiple-choice treatment based on the complex interaction of the tumour stage, the degree of liver disease, and the patient's general state of health.

Methods:

In this paper, we reviewed new insights into nonsurgical and surgical treatment of liver cancer in five English databases, including Scopus, PubMed, Web of Science, EMBASE, and Google Scholar up to December 2019.

Results:

The results demonstrated, in addition to current therapies such as chemotherapy and surgical resection, new approaches, including immunotherapy, viral therapy, gene therapy, new ablation therapies, and adjuvant therapy, are widely used for the treatment of HCC. In recent years, biomaterials such as nanoparticles, liposomes, microspheres, and nanofibers are also regarded as reliable and innovative patents for the treatment and study of liver cancers.

Conclusion:

Multidisciplinary and multi-choice treatments and therapies are available for this liver cancer, while there are differences in liver cancer management recommendations among specialties and geographic areas. Current results have shown that treatment strategies have been combined with the advancement of novel treatment modalities. In addition, the use of new approaches with greater efficacy, such as combination therapy, biomaterials, ablation therapy, etc. can be considered the preferred treatment for patients.

Noble Metals for Modern Implant Materials: MOCVD of Film Structures and Cytotoxical, Antibacterial, and Histological Studies

This work is aimed at developing the modification of the surface of medical implants with film materials based on noble metals in order to improve their biological characteristics. Gas-phase transportation methods were proposed to obtain such materials. To determine the effect of the material of the bottom layer of heterometallic structures, Ir, Pt, and PtIr coatings with a thickness of 1.4-1.5 μm were deposited by metal-organic chemical vapor deposition (MOCVD) on Ti₆Al₄V alloy discs. Two types of antibacterial components, namely, gold nanoparticles (AuNPs) and discontinuous Ag coatings, were deposited on the surface of these coatings. AuNPs (11-14 nm) were deposited by a pulsed MOCVD method, while Ag films (35-40 nm in thickness) were obtained by physical vapor deposition (PVD). The cytotoxic (24 h and 48 h, toward peripheral blood mononuclear cells (PBMCs)) and antibacterial (24 h) properties of monophase (Ag, Ir, Pt, and PtIr) and heterophase (Ag/Pt, Ag/Ir, Ag/PtIr, Au/Pt, Au/Ir, and Au/PtIr) film materials deposited on Ti-alloy samples were studied in vitro and compared with those of uncoated Ti-alloy samples. Studies of the cytokine production by PBMCs in response to incubation of the samples for 24 and 48 h and histological studies at 1 and 3 months after subcutaneous implantation in rats were also performed. Despite the comparable thickness of the fibrous capsule after 3 months, a faster completion of the active phase of encapsulation was observed for the coated implants compared to the Ti alloy analogs. For the Ag-containing samples, growth inhibition of S. epidermidis, S. aureus, Str. pyogenes, P. aeruginosa, and Ent. faecium was observed.

Toxicity of gold nanoparticles (AuNPs): A review

Gold nanoparticles are a kind of nanomaterials that have received great interest in field of biomedicine due to their electrical, mechanical, thermal, chemical and optical properties. With these great potentials came the consequence of their interaction with biological tissues and molecules which presents the possibility of toxicity. This paper aims to consolidate and bring forward the studies performed that evaluate the toxicological aspect of AuNPs which were categorized into in vivo and in vitro studies. Both indicate to some extent oxidative damage to tissues and cell lines used in vivo and in vitro respectively with the liver, spleen and kidney most affected. The outcome of these review showed small controversy but however, the primary toxicity and its extent is collectively determined by the characteristics, preparations and physicochemical properties of the NPs. Some studies have shown that AuNPs are not toxic, though many other studies contradict this statement. In order to have a holistic inference, more studies are required that will focus on characterization of NPs and changes of physical properties before and after treatment with biological media. So also, they should incorporate controlled experiment which includes supernatant control Since most studies dwell on citrate or CTAB-capped AuNPs, there is the need to evaluate the toxicity and pharmacokinetics of functionalized AuNPs with their surface composition which in turn affects their toxicity. Functionalizing the NPs surface with more peculiar ligands would however help regulate and detoxify the uptake of these NPs.

Chitosan-Coated Gold Nanoparticles Induce Low Cytotoxicity and Low ROS Production in Primary Leucocytes, Independent of Their Proliferative Status

(1) Background: Chitosan-coated gold nanoparticles (CH-AuNPs) have important theranostic applications in biomedical sciences, including cancer research. However, although cell cytotoxicity has been studied in cancerous cells, little is known about their effect in proliferating primary leukocytes. Here, we assessed the effect of CH-AuNPs and the implication of ROS on non-cancerous endothelial and fibroblast cell lines and in proliferative lymphoid cells. (2) Methods: The Turkevich method was used to synthetize gold nanoparticles. We tested cell viability, cell death, ROS production, and cell cycle in primary lymphoid cells, compared with non-cancer and cancer cell lines. Concanavalin A (ConA) or lipopolysaccharide (LPS) were used to induce proliferation on lymphoid cells. (3) Results: CH-AuNPs presented high cytotoxicity and ROS production against cancer cells compared to non-cancer cells; they also induced a different pattern of ROS production in peripheral blood mononuclear cells (PBMCs). No significant cell-death difference was found in PBMCs, splenic mononuclear cells, and bone marrow cells (BMC) with or without a proliferative stimuli. (4) Conclusions: Taken together, our results highlight the selectivity of CH-AuNPs to cancer cells, discarding a consistent cytotoxicity upon proliferative cells including endothelial, fibroblast, and lymphoid cells, and suggest their application in cancer treatment without affecting immune cells.

Gold nanoparticles: synthesis, physiochemical properties and therapeutic applications in cancer

Gold nanoparticles (AuNPs) have been shown to be useful as carriers of various anticancer drugs as well as diagnosis platforms. In this review, we discuss the synthesis and physiochemical properties of AuNPs. We also highlight the photothermal and photodynamic properties of AuNPs and relevant applications in therapeutic studies. Furthermore, we review the applications of AuNPs in cancer treatment as and their underlying anticancer mechanisms in multiple types of cancer.

Cellular uptake and toxicity of gold nanoparticles on two distinct hepatic cell models

Gold nanoparticles (AuNPs) have huge potential for various biomedical applications, but their successful use depends on their uptake and possible toxicity in the liver, their main site for accumulation. Therefore, in this work we compared the cytotoxic effects induced by AuNPs with different size (~ 15 nm and 60 nm), shape (nanospheres and nanostars) and capping [citrate- or 11-mercaptoundecanoic acid (MUA)], in human HepaRG cells or primary rat hepatocytes (PRH) cultivated with serum-free or Foetal Bovine Serum (FBS)-supplemented media. The safety assessment of the AuNPs demonstrated that overall they present low toxicity towards hepatic cells. Among all the tested AuNPs, the smaller 15 nm spheres displayed the highest toxicity. The toxicological effect was capping, size and cell-type dependent with citrate-capping more toxic than MUA (PRH with FBS), the 15 nm AuNPs more toxic than 60 nm counterparts and PRH more sensitive, as compared to the HepaRG cells. The incubation with FBS-free media produced aggregation of AuNPs while its presence greatly influenced the toxicity outcomes. The cellular uptake of AuNPs was shape, size and capping dependent in PRH cultivated in FBS-supplemented media, and significantly different between the two types of cells with extensively higher internalization of AuNPs in PRH, as compared to the HepaRG cells. These data show that the physical-chemical properties of AuNPs, including size and shape, as well as the type of cellular model, greatly influence the interaction of the AuNPs with the biological environment and consequently, their toxicological effects.

Laser Responsive Cisplatin-Gold Nano-Assembly Synergizes the Effect of Cisplatin With Compliance

Cisplatin therapy faces low bioavailability and clastogenic potential limitations. Early payload leakage of nanocarriers may impair adequate therapeutic efficacy. We propose encapsulation of cisplatin in such nanocarrier that can be externally stimulated for high payload release and enhanced toxicity at site of action. Cisplatin conjugated gold nanorods (Pt-AuNRs) have been synthesized and characterized through UV visible spectroscopy, dynamic light scattering and transmission electron microscopy. Physico-chemical characterization through X-ray photon spectrometry confirms the covalent linkage between linker and aquated cisplatin with AuNRs. Laser exposure (850 nm, CW) enabled ~15-fold payload release from Pt-AuNRs nano-assembly, which is quite high (P < 0.0001) compared to non-stimulated conditions. The median growth inhibitory concentration (GI₅₀) after laser exposure of Pt-AuNRs was ~11- and 13-fold low compared to corresponding Pt-AuNRs without laser exposure and cisplatin respectively, in sarcoma cells. Synergistic therapeutic difference is more significant (P < 0.01), at lower concentrations of Pt-AuNRs (0.5-10 μg/mL). Pt-AuNRs photothermal therapy indicates a convincible association of over-production of reactive oxygen species (P < 0.0001) and synergistic therapeutic efficacy. Clastogenic potential is found non-significant for Pt-AuNRs (10 μg/mL). Cisplatin nanoconjugate shows biocompatibility against blood cells. In conclusion, laser-stimulated Pt-AuNRs appear a promising drug delivery with synergistic toxic potential against cancer while attenuating cisplatin toxicity.

Effects of single and combined exposures of gold (nano versus ionic form) and gemfibrozil in a liver organ culture of Sparus aurata

In vitro methods have gained rising importance in ecotoxicology due to ethical concerns. The aim of this study was to assess the single and combined in vitro effects of gold, as nanoparticle (AuNPs) and ionic (Au⁺) form, and the pharmaceutical gemfibrozil (GEM). Sparus aurata liver organ culture was exposed to gold (4 to 7200 μg·L^-1), GEM (1.5 to 15,000 μg·L^-1) and combination 80 μg·L^-1 gold +150 μg·L^-1 GEM for 24 h. Endpoints related with antioxidant status, peroxidative/genetic damage were assessed. AuNPs caused more effects than Au⁺, increasing catalase and glutathione reductase activities and damaging DNA and cellular membranes. Effects were dependent on AuNPs size, coating and concentration. GEM damaged DNA at an environmentally relevant concentration, 1.5 μg·L^-1. Overall, the effects of the combined exposures were higher than the predicted, based on single exposures. This study showed that liver culture can be a useful model to study contaminants effects.

Synthesis of Biogenic Gold Nanoparticles from Terminalia mantaly Extracts and the Evaluation of Their In Vitro Cytotoxic Effects in Cancer Cells

Scientists have demonstrated the potential of plant materials as ‘green’ reducing and stabilizing agents for the synthesis of gold nanoparticles (AuNPs) and opened new ecofriendly horizons to develop effective and less harmful treatment strategies. The current study demonstrated the use of Terminalia mantaly (TM) extracts to synthesize AuNPs with enhanced cytotoxic effects. The TM-AuNPs were synthesized at 25 and 70 °C using water (_WTM) and methanolic (_MTM) extracts of the leaf, root and stem/bark parts of the plant. The TM-AuNPs were characterized using UV–visible spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy, energy dispersive X-ray (EDX), selection area electron diffraction (SAED) and Fourier transform infrared (FTIR) spectroscopy. Majority of the TM-AuNPs were spherical with a mean diameter between 22.5 and 43 nm and were also crystalline in nature. The cytotoxic effects of TM-AuNPs were investigated in cancer (Caco-2, MCF-7 and HepG2) and non-cancer (KMST-6) cell lines using the MTT assay. While the plant extracts showed some cytotoxicity towards the cancer cells, some of the TM-AuNPs were even more toxic to the cells. The IC₅₀ values (concentrations of the AuNPs that inhibited 50% cell growth) as low as 0.18 µg/mL were found for TM-AuNPs synthesized using the root extract of the plant. Moreover, some of the TM-AuNPs demonstrated selective toxicity towards specific cancer cell types. The study demonstrates the potential of TM extracts to produce AuNPs and describe the optimal conditions for AuNPs using TM extracts. The toxicity of some the TM-AuNPs can possibly be explored in the future as an antitumor treatment.

Nanomaterials for oncotherapies targeting the hallmarks of cancer

An increasing amount of evidence has demonstrated the diverse functionalities of nanomaterials in oncotherapies such as drug delivery, imaging, and killing cancer cells. This review aims to offer an authoritative guide for the development of nanomaterial-based oncotherapies and shed light on emerging yet understudied hallmarks of cancer where nanoparticles can help improve cancer control. With this aim, three nanomaterials, i.e. those based on gold, graphene, and liposome, were selected to represent and encompass metal inorganic, nonmetal inorganic, and organic nanomaterials, and four oncotherapies, i.e. phototherapies, immunotherapies, cancer stem cell therapies, and metabolic therapies, were characterized based on the differential hallmarks of cancer that they target. We also view physical plasma as a cocktail of reactive species and carrier of nanomaterials and focus on its roles in targeting the hallmarks of cancer provided with its unique traits and ability to selectively induce epigenetic and genetic modulations in cancer cells that halt tumor initiation and progression. This review provides a clear understanding of how the physico-chemical features of particles at the nanoscale contribute alone or create synergistic effects with current treatment modalities in combating each of the hallmarks of cancer that ultimately leads to desired therapeutic outcomes and shapes the toolbox for cancer control.

Mechano-Informed Biomimetic Polymer Scaffolds by Incorporating Self-Powered Zinc Oxide Nanogenerators Enhance Motor Recovery and Neural Function

Piezoelectric materials can produce electrical power from the mechanical stimulation and thus, they may accelerate electroactive tissue healing as a promising treatment for traumatic peripheral nerve injuries. In this study, a piezoelectric zinc oxide nanogenerator scaffold is manufactured by 3D injectable multilayer biofabrication. The piezoelectric polymeric scaffold displays desirable mechanical and physical characteristics, such as aligned porosity, high elasticity, scaffold stiffness, surface energy, and excellent shear behavior. In addition, its biocompatibility supplies Schwann cells with an adhesive, proliferative, and angiogenic interface, as is reflected by higher expression of functional proteins including nerve growth factor (NGF) and vascular endothelial growth factor (VEGF). In vivo mechanical stimuli by treadmill practice contribute to the comprehensive reparative therapy. The piezoelectric conduit accelerates nerve conducting velocity, promotes axonal remyelination, and restores motor function by recovering endplate muscles. Moreover, the piezoelectric nanogenerator scaffold creates biomimetic electrically conductive microenvironment without causing noticeable toxicity to functioning organs and improves peripheral nerve restoration by the multifunctional characteristics. Therefore, the mechano-informed biomimetic piezoelectric scaffold may have enormous potential in the neuroengineering for regenerative medicine.

Nanotechnology-based Drug Delivery, Metabolism and Toxicity

BACKGROUND

Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern.

OBJECTIVE

The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics.

METHODS

Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models.

RESULTS

Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices.

CONCLUSION

The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Susceptibility of HepG2 Cells to Silver Nanoparticles in Combination with other Metal/Metal Oxide Nanoparticles

The fast-growing use of nanomaterials in everyday life raises the question about the safety of their use. Unfortunately, the risks associated with the use of nanoparticles (NPs) have not yet been fully assessed. The majority of studies conducted so far at the molecular and cellular level have focused on a single-type exposure, assuming that NPs act as the only factor. In the natural environment, however, we are likely exposed to a mixture of nanoparticles, whose interactions may modulate their impact on living organisms. This study aimed to evaluate the toxicological effects caused by in vitro exposure of HepG2 cells to AgNPs in combination with AuNPs, CdTe quantum dot (QD) NPs, TiO₂NPs, or SiO₂NPs. The results showed that the toxicity of nanoparticle binary mixtures depended on the type and ratio of NPs used. In general, the toxicity of binary mixtures of NPs was lower than the sum of toxicities of NPs alone (protective effect).

GOLD: human exposure and update on toxic risks

Gold is ubiquitous in the human environment and most people are in contact with it through wearing jewelry, dental devices, implants or therapies for rheumatoid arthritis. Gold is not a nutrient but people are exposed to it as a food colorant and in food chains. The present review discusses the hazards faced in personal and domestic use of gold and the far greater risks presented through occupational exposure to the metal in mining and processing gold ores. In the last situation, regular manual contact or inhalation of toxic or carcinogenic materials like mercury or arsenic, respectively, presents far greater hazard and greatly complicates the evaluation of gold toxicity. The uses and risks presented by new technology and use of nanoparticulate gold in anti-cancer therapies and diagnostic medicine forms a major consideration in gold toxicity, where tissue uptake and distribution are determined largely by particle size and surface characteristics. Many human problems arise through the ability of metallic gold to induce allergic contact hypersensitivity. While gold in jewelry can evoke allergic reactions, other metals such as nickel, chromium and copper present in white gold or alloys exhibit more serious clinical problems. It is concluded that toxic risks associated with gold are low in relation to the vast range of potential routes of exposure to the metal in everyday life.

Preparation of Cu nanoparticles fixed on cellulosic walnut shell material and investigation of its antibacterial, antioxidant and anticancer effects

In this study, antibacterial, antioxidant, and anticancer effects of Cu nanoparticles (CuNPs) fixed on cellulosic walnut shell material were investigated. Firstly, three types of walnut shell-supported copper nanoparticles with various sizes (CuNP-WS1 15–22 nm, CuNP-WS2 60–80 nm and, CuNP-WS3 aggregated of metallic nanoparticles) were synthesized. Antibacterial properties of CuNPs were studied on three strains of bacteria; Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes. DPPH (1, 1-Diphenyl-2-picrylhydrazyl) method was used to examining antioxidant properties. Cytotoxic effects of the synthesized nanoparticles on the cancer cell line were studied. Antimicrobial properties of CuNPs showed that these nanomaterials affect both Gram-positive and Gram-negative bacteria. The antioxidant properties of CuNPs increased significantly by increasing the concentration to 10%. CuNPs appeared to have a dose-dependent cytotoxic effect on K562 cells. However, the IC50 of the synthesized nanoparticles against the K562 (25.24 ± 5 μg/mL) cancer cells was lower significantly (P < 0.01) of the IC50 of these compounds against PBMCs (42.54 ± 6.2 μg/mL).

Size, Surface Functionalization, and Genotoxicity of Gold Nanoparticles In Vitro

Several studies suggested that gold nanoparticles (NPs) could be genotoxic in vitro and in vivo. However, gold NPs currently produced present a wide range of sizes and functionalization, which could affect their interactions with the environment or with biological structures and, thus, modify their toxic effects. In this study, we investigated the role of surface charge in determining the genotoxic potential of gold NPs, as measured by the induction of DNA damage (comet assay) and chromosomal damage (micronucleus assay) in human bronchial epithelial BEAS-2B cells. The cellular uptake of gold NPs was assessed by hyperspectral imaging. Two core sizes (~5 nm and ~20 nm) and three functionalizations representing negative (carboxylate), positive (ammonium), and neutral (poly(ethylene glycol) (PEG)ylated) surface charges were examined. Cationic ammonium gold NPs were clearly more cytotoxic than their anionic and neutral counterparts, but genotoxicity was not simply dependent on functionalization or size, since DNA damage was induced by 20-nm ammonium and PEGylated gold NPs, while micronucleus induction was increased by 5-nm ammonium and 20-nm PEGylated gold NPs. The 5-nm carboxylated gold NPs were not genotoxic, and evidence on the genotoxicity of the 20-nm carboxylated gold NPs was restricted to a positive result at the lowest dose in the micronucleus assay. When interpreting the results, it has to be taken into account that cytotoxicity limited the doses available for the ammonium-functionalized gold NPs and that gold NPs were earlier described to interfere with the comet assay procedure, possibly resulting in a false positive result. In conclusion, our findings show that the cellular uptake and cytotoxicity of gold NPs are clearly enhanced by positive surface charge, but neither functionalization nor size can single-handedly account for the genotoxic effects of the gold NPs.

Liver Cancer: Current and Future Trends Using Biomaterials

Hepatocellular carcinoma (HCC) is the fifth most common type of cancer diagnosed and the second leading cause of death worldwide. Despite advancement in current treatments for HCC, the prognosis for this cancer is still unfavorable. This comprehensive review article focuses on all the current technology that applies biomaterials to treat and study liver cancer, thus showing the versatility of biomaterials to be used as smart tools in this complex pathologic scenario. Specifically, after introducing the liver anatomy and pathology by focusing on the available treatments for HCC, this review summarizes the current biomaterial-based approaches for systemic delivery and implantable tools for locally administrating bioactive factors and provides a comprehensive discussion of the specific therapies and targeting agents to efficiently deliver those factors. This review also highlights the novel application of biomaterials to study HCC, which includes hydrogels and scaffolds to tissue engineer 3D in vitro models representative of the tumor environment. Such models will serve to better understand the tumor biology and investigate new therapies for HCC. Special focus is given to innovative approaches, e.g., combined delivery therapies, and to alternative approaches-e.g., cell capture-as promising future trends in the application of biomaterials to treat HCC.

The Synergistic Cytotoxic Effect of Laser-Irradiated Gold Nanoparticles and Sorafenib Against the Growth of a Human Hepatocellular Carcinoma Cell Line

Gold nanoparticles are the most promising candidate in cancer treatment due to their physiochemical properties and increased use in photothermal therapy (PTT). In the present study, spherical gold nanoparticles (AuNPs) were synthesized using citrate reduction method. The particles were then characterized using UV-VIS spectroscopy and transmission electron microscope. A hepatocellular carcinoma cell line (HepG2) was incubated with sorafenib and/or non-irradiated or laser-irradiated AuNPs for 48 hrs. The cytotoxic effect of different treatment modalities was determined using MTT assay. Furthermore, apoptosis was determined by flow cytometry using annexin V/propidium iodide, as well as estimating the level of caspases. Results showed that AuNPs and sorafenib reduced HepG2 cell viability, and the cytotoxicity was associated with increased release of LDH in the culture medium. The recorded cytotoxicity was attributed to enhanced apoptosis as revealed by increased cellular caspases (3, 8 and 9), that was further confirmed by flow cytometry. The most notable cytotoxic effect was recorded when combining sorafenib with laser-irradiated AuNPs. In conclusion, a synergistic cytotoxic effect was observed between sorafenib and laser-irradiated AuNPs against the growth of HepG2, suggesting the potential substitution of large toxic doses of sorafenib by lower doses in combination with photothermal therapy.

Biosafety of unmodified ultrafine gold particles (AuPs) upon interacting with human blood components before systemic use

Ultrafine gold particles (AuPs) can be emerged as a good candidate in the field of drug delivery as well as in imaging applications. However, little attention has been paid to detailed study of nanoparticle's interaction with blood components before systemic use. An investigation into the interaction of ultrafine AuPs with blood components is must for its clinical application. In present study, the interaction of ultrafine sized AuPs (2 ± 0.5 nm, 5 ± 1 nm, and 10 ± 2 nm) with blood components and its immunogenic property (pro-inflammatory reaction) was investigated. All three sized AuPs did not cause any significant hemolysis. Plasma coagulation study showed significant increase in Prothrombin time (PT) with International Normalized Ratio (INR) value raised to 1.53 with 10 nm AuPs. Maximum prolongation of activated partial thromboplastin time (APTT) (3.2 s) was seen with 5 &10 nm sized AuPs. Maximum thrombin time (TT) prolongation was seen with 2 nm (18.3s) with the difference of 1.4 s as compared to control. Platelet aggregation was faster in case of 5 & 10 nm sized AuPs. All three sized AuPs exhibited in-vitro C3 complement activation whereas they did not stimulate significant proliferation of peripheral blood mononuclear cells (PBMC). These findings further validate the utility of ultrafine AuPs for in-vivo applications.

Intrinsic Effects of Gold Nanoparticles on Oxygen-Glucose Deprivation/Reperfusion Injury in Rat Cortical Neurons

This study aimed to investigate the potential effects of gold nanoparticles (Au-NPs) on rat cortical neurons exposed to oxygen-glucose deprivation/reperfusion (OGD/R) and to elucidate the corresponding mechanisms. Primary rat cortical neurons were exposed to OGD/R, which is commonly used in vitro to mimic ischemic injury, and then treated with 5- or 20-nm Au-NPs. We then evaluated cell viability, apoptosis, oxidative stress, and mitochondrial respiration in these neurons. We found that 20-nm Au-NPs increased cell viability, alleviated neuronal apoptosis and oxidative stress, and improved mitochondrial respiration after OGD/R injury, while opposite effects were observed for 5-nm Au-NPs. In terms of the underlying mechanisms, we found that Au-NPs could regulate Akt signaling. Taken together, these results show that 20-nm Au-NPs can protect primary cortical neurons against OGD/R injury, possibly by decreasing apoptosis and oxidative stress, while activating Akt signaling and mitochondrial pathways. Our results suggest that Au-NPs may be potential therapeutic agents for ischemic stroke.

Genotoxicity of gold nanoparticles in the gilthead seabream (Sparus aurata) after single exposure and combined with the pharmaceutical gemfibrozil

Due to their diverse applications, gold nanoparticles (AuNPs) are expected to increase of in the environment, although few studies are available on their mode of action in aquatic organisms. The genotoxicity of AuNPs, alone or combined with the human pharmaceutical gemfibrozil (GEM), an environmental contaminant frequently detected in aquatic systems, including in marine ecosystems, was examined using gilthead seabream erythrocytes as a model system. Fish were exposed for 96 h to 4, 80 and 1600 μg L^-1 of 40 nm AuNPs with two coatings - citrate or polyvinylpyrrolidone; GEM (150 μg L^-1); and a combination of AuNPs and GEM (80 μg L^-1 AuNPs + 150 μg L^-1 GEM). AuNPs induced DNA damage and increased nuclear abnormalities levels, with coating showing an important role in the toxicity of AuNPs to fish. The combined exposures of AuNPs and GEM produced an antagonistic response, with observed toxic effects in the mixtures being lower than the predicted. The results raise concern about the safety of AuNPs and demonstrate interactions between them and other contaminants.

Impact of gold nanoparticles shape on their cytotoxicity against human osteoblast and osteosarcoma in in vitro model. Evaluation of the safety of use and anti-cancer potential

Due to development of nanotechnology and gold nanoparticles (AuNPs) increasing use in different areas of medicine, especially in oncology, better understanding of their potential cytotoxicity is necessary to protect patients safety. Shape and size of AuNPs is an important modulator of their cytotoxicity. Therefore, we investigated the cytotoxicity of AuNPs rods (≈39 nm length, 18 nm width), AuNPs stars (≈ 215 nm) and AuNPs spheres (≈ 6.3 nm) against human fetal osteoblast (hFOB 1.19), osteosarcoma (143B, MG63) and pancreatic duct cell (hTERT-HPNE) lines by MTT and neutral-red uptake assay. Moreover, influence of AuNPs on level of proapoptotic protein (Bax) and anti-apoptotic protein (Bcl-2) was measured by western blot. Cellular uptake of nanoparticles and ultrastructure changes were examined by transmission electron microscopy (TEM). In the present study we have proven that AuNPs stars are the most cytotoxic against human cells. We observed that cancer cells are more susceptible to AuNPs cytotoxic effect. Furthermore, AuNPs rods and AuNPs stars caused increased expression of Bax and decreased expression of Bcl-2 protein in osteosarcoma cells. We found that AuNPs penetrated through the cell membrane and caused ultrastructural changes. Our results clearly demonstrated that the cytotoxicity of AuNPs was shape-dependent. AuNPs stars with the highest anti-cancer potential were also the most cytotoxic type of tested NPs, whereas AuNPs spheres which appears to be the safest one had small anti-cancer potential.

Safety assessment of Piper cernuum Vell. (Piperaceae) leaves extract: Acute, sub-acute toxicity and genotoxicity studies

ETHNOPHARMACOLOGICAL RELEVANCE

Piper cernuum Vell (Piperaceae) is a native species from Atlantic rain forest, popularly known as pariparoba. Its leaves have been commonly used by rural and urban communities from State of São Paulo, Brazil, to treat pain (orally and topically), and hepatic and renal complications.

AIM OF THE STUDY

In this study we evaluated the acute and sub-acute toxicity, genotoxicity and mutagenicity of hydroalcoholic extract obtained from P. cernuum leaf using in vivo and in vitro methods.

MATERIAL AND METHODS

In the acute toxicity study, mice were orally treated with P. cernuum extract (2000 mg/kg, p.o.). General behavior and mortality were observed for up to 14 days. In the sub-acute toxicity study, P. cernuum extract was given orally as a single administration to the rats at doses of 50 or 250 mg/kg/day, for 28 days. General behavior, body weight, biochemical and hematological parameters, organ coefficients and pathological morphology were analyzed. The P. cernuum mutagenicity was evaluated using mammalian cell micronucleus assay. Additionally, in vitro toxicity profile of the extract was assessed through cytotoxicity, hemolytic activity, and genotoxicity assay.

RESULTS

Data from comet assay demonstrates that high concentrations of P. cernuum extract induce genotoxicity. However, no evidence of hemolytic, cytotoxic or mutagenicity activity was found. In addition, the acute and sub-acute toxicity studies did not show significant changes in body weight, general behavior, hematology and biochemical parameters, organ weight and liver and kidney histopathological analysis.

CONCLUSIONS

Together, the results herein obtained indicate that P. cernuum leaves extract did not present significant toxicity when administered to male or female rats. Additionally, no significant alteration in hematological, biochemical and morphological parameters were observed. Data obtained in vitro shows that extract did not present cytotoxicity and mutagenicity. However, the extract induces in vitro genotoxicity, but in high concentration. Further studies are necessary to evaluate the safety of long-term exposure to P. cernuum leaves extract added to in vivo genotoxicity.

Effects and bioaccumulation of gold nanoparticles in the gilthead seabream (Sparus aurata) - Single and combined exposures with gemfibrozil

Gold nanoparticles (AuNPs) are found in a wide range of applications and therefore expected to present increasing levels in the environment. There is however limited knowledge concerning the potential toxicity of AuNPs as well as their combined effects with other pollutants. Hence, the present study aimed to investigate the effects of AuNPs alone and combined with the pharmaceutical gemfibrozil (GEM) on different biological responses (behaviour, neurotransmission, biotransformation and oxidative stress) in one of the most consumed fish in southern Europe, the seabream Sparus aurata. Fish were exposed for 96 h to waterborne 40 nm AuNPs with two coatings - citrate and polyvinylpyrrolidone (PVP), alone or combined with GEM. Antioxidant defences were induced in liver and gills upon both AuNPs exposure. Decreased swimming performance (1600 μg.L^-1) and oxidative damage in gills (4 and 80 μg.L^-1) were observed following exposure to polyvinylpyrrolidone coated gold nanoparticles (PVP-AuNPs). Generally, accumulation of gold in fish tissues and deleterious effects in S. aurata were higher for PVP-AuNPs than for cAuNPs exposures. Although AuNPs and GEM combined effects in gills were generally low, in liver, they were higher than the predicted. The accumulation and effects of AuNPs showed to be dependent on the size, coating, surface charge and aggregation/agglomeration state of nanoparticles. Additionally, it was tissue' specific and dependent on the presence of other contaminants. Although, gold intake by humans is expected to not exceed the estimated tolerable daily intake, it is highly recommended to keep it on track due to the increasing use of AuNPs.

Biological monitoring of workers exposed to engineered nanomaterials

As the number of nanomaterial workers increase there is need to consider whether biomonitoring of exposure should be used as a routine risk management tool. Currently, no biomonitoring of nanomaterials is mandated by authoritative or regulatory agencies. However, there is a growing knowledge base to support such biomonitoring, but further research is needed as are investigations of priorities for biomonitoring. That research should be focused on validation of biomarkers of exposure and effect. Some biomarkers of effect are generally nonspecific. These biomarkers need further interpretation before they should be used. Overall biomonitoring of nanomaterial workers may be important to supplement risk assessment and risk management efforts.

Size-dependent genotoxicity of silver, gold and platinum nanoparticles studied using the mini-gel comet assay and micronucleus scoring with flow cytometry

Metallic nanoparticles (NPs) are promising nanomaterials used in different technological solutions as well as in consumer products. Silver (Ag), gold (Au) and platinum (Pt) represent three metallic NPs with current or suggested use in different applications. Pt is also used as vehicle exhaust catalyst leading to a possible exposure via inhalation. Despite their use, there is limited data on their genotoxic potential and possible size-dependent effects, particularly for Pt NPs. The aim of this study was to explore size-dependent genotoxicity of these NPs (5 and 50 nm) following exposure of human bronchial epithelial cells. We characterised the NPs and assessed the viability (Alamar blue assay), formation of DNA strand breaks (mini-gel comet assay) and induction of micronucleus (MN) analysed using flow cytometry (in vitro microflow kit). The results confirmed the primary size (5 and 50 nm) but showed agglomeration of all NPs in the serum free medium used. Slight reduced cell viability (tested up to 50 µg/ml) was observed following exposure to the Ag NPs of both particle sizes as well as to the smallest (5 nm) Au NPs. Similarly, at non-cytotoxic concentrations, both 5 and 50 nm-sized Ag NPs, as well as 5 nm-sized Au NPs, increased DNA strand breaks whereas for Pt NPs only the 50 nm size caused a slight increase in DNA damage. No clear induction of MN was observed in any of the doses tested (up to 20 µg/ml). Taken together, by using the comet assay our study shows DNA strand breaks induced by Ag NPs, without any obvious differences in size, whereas effects from Au and Pt NPs were size-dependent in the sense that the 5 nm-sized Au NPs and 50 nm-sized Pt NPs particles were active. No clear induction of MN was observed for the NPs.

Assessment of Gold Nanoparticles-Inhibited Cytochrome P450 3A4 Activity and Molecular Mechanisms Underlying Its Cellular Toxicity in Human Hepatocellular Carcinoma Cell Line C3A

Interactions of the 40 and 80 nm gold nanoparticles (AuNP) functionalized with cationic branched polyethylenimine (BPEI), anionic lipoic acid (LA), or neutral polyethylene glycol (PEG) with human hepatocellular carcinoma (HCC) cell line C3A have been investigated in the absence and presence of human plasma protein corona (PC). All bare (no PC) AuNP besides 80 nm LA-AuNP were cytotoxic to C3A but PC attenuated their cytotoxicities. Time-dependent cellular uptake of AuNP increased besides 40 nm BPEI-AuNP but PC suppressed their uptakes besides 80 nm PEG-AuNP. Biphasic responses of oxidative/nitrosative stress by BPEI-AuNP occurred in C3A cells, whereas PEG-AuNP was a potent antioxidant. All bare AuNP inhibited cytochrome P450 (CYP) 3A4 activity irrespective of size and surface charge but PC recuperated its activity besides PEG-AuNP. The 40 nm PEG-AuNP-modulated gene expression was mainly involved in mitochondrial fatty acid β-oxidation and to a less degree hepatic efflux/uptake transporters. These studies contribute to a better understanding of AuNP interaction with key biological processes and their underlying molecular mechanisms in HCC, which may be further implicated in the development of more effective therapeutic target in HCC treatment.

Modulation of immune genes mRNA levels in mucosal tissues and DNA damage in red blood cells of Sparus aurata by gold nanoparticles

Gold nanoparticles (AuNP) effects on Sparus aurata were evaluated on skin, gills and intestine by assessing the expression of immune genes and in peripheral blood evaluating genetic damage. Fish were exposed to 0.5 and 50 μg/L AuNP for 96 h. Results showed that exposure to 50 μg/L AuNP induced an upregulation in the expression of innate immune genes in gills (c3, lys, il1β, tnfα, il6, il10 and tgfβ) and intestine (il1β, tnfα and il6). Furthermore, mRNA levels of hsp70 and hsp90 were increased in gills after exposure to 0.5 μg/L AuNP, when compared to 50 μg/L. Present data demonstrated the sensitivity of gills and intestines to AuNP exposure supporting their use in the study of fish responses to other nanoparticles. Genotoxic potential of AuNP was demonstrated by increased DNA strand breaks in red blood cells of fish exposed to AuNP, suggesting that AuNP represent a potential hazard to fish.

Silver and gold nanoparticles from tannic acid: synthesis, characterization and evaluation of antileishmanial and cytotoxic activities

Gold (Au0) and silver (Ag0) nanoparticles were synthesized using tannic acid (TA) as both reducing and stabilizer. Nanoparticles formation, stability, and interaction with TA were compared to citrate-coated nanoparticles and monitored by UV-Vis, zeta potential, and transmission electron microscopy. TA coating resulted in a red-shift and broadening of bands compared to citrate-coated nanoparticles (NPs-Cit). AgNPs-TA and AuNPs-TA are negatively charged with mean surface charge of -29.4 mV and -29.6 mV, respectively. TEM images showed polydispersety of AuNPs-TA (6-42 nm) and aggregation of AgNPs-TA (12-71 nm). In vitro assays of Leishmania amazonensis promastigotes showed an increment of antileishmanial activity for AgNPs-TA in relation to AgNPs-Cit, while AuNPs-TA and AuNPs-Cit did not affect the protozoas at tested concentrations. CC50 value for AgNPs-TA suggested that TA attenuates nanosilver toxicity comparatively to its precursor (Ag+). This investigation can contribute to the development of new, green, and fast produced drugs aiming at leishmaniasis treatment.

From the Cover: An Investigation of the Genotoxicity and Interference of Gold Nanoparticles in Commonly Used In Vitro Mutagenicity and Genotoxicity Assays

The suitability of 4 in vitro assays, commonly used for mutagenicity and genotoxicity assessment, was investigated in relation to treatment with 14 nm citrate-stabilized gold nanoparticles (AuNPs). Specifically, the Ames test was conducted without metabolic activation, where no mutagenic effects were observed. High resolution transmission electron microscopy and Cytoviva dark-field image analysis showed that AuNPs did not enter the bacterial cells, thus confirming the unreliability of the Ames test for nanoparticle mutagenicity studies. In addition, the Chinese hamster ovary (CHO) cell line was used for Comet, Chromosome aberration and Micronucleus assays. CHO cells were treated with AuNPs for 20 h at 37 °C. Cytotoxicity was not detected by cell impedance studies even though AuNP uptake was confirmed using Cytoviva image analysis. The DNA damage was statistically significant in treated cells when assessed by the Comet assay. However, minimal and nonstatistically significant chromosomal DNA damage was observed using the chromosome aberration and micronucleus assays. In this study, we showed that false positive results obtained with Comet assay may have been due to the possibility of direct contact between the residual, intracellular AuNPs and DNA during the assay procedure. Therefore, the chromosome aberration and micronucleus assays are better suited to assess the genotoxic effects of nanoparticles due to low probability of such direct contact occurring. Genotoxic effect of 14 and 20 nm citrate-stabilized, as well as, 14 nm PCOOH AuNPs were also investigated using chromosome aberration and micronucleus assays. Based on our acceptance criteria for a positive genotoxic response, none of the AuNPs were found to be genotoxic in either of these assays.