Current opinion on nanotoxicology

Nanotechnology in the Diagnosis and Treatment of Antibiotic-Resistant Infections

The development of antimicrobial resistance (AMR), along with the relative reduction in the production of new antimicrobials, significantly limits the therapeutic options in infectious diseases. Thus, novel treatments, especially in the current era, where AMR is increasing, are urgently needed. There are several ongoing studies on non-classical therapies for infectious diseases, such as bacteriophages, antimicrobial peptides, and nanotechnology, among others. Nanomaterials involve materials on the nanoscale that could be used in the diagnosis, treatment, and prevention of infectious diseases. This review provides an overview of the applications of nanotechnology in the diagnosis and treatment of infectious diseases from a clinician's perspective, with a focus on pathogens with AMR. Applications of nanomaterials in diagnosis, by taking advantage of their electrochemical, optic, magnetic, and fluorescent properties, are described. Moreover, the potential of metallic or organic nanoparticles (NPs) in the treatment of infections is also addressed. Finally, the potential use of NPs in the development of safe and efficient vaccines is also reviewed. Further studies are needed to prove the safety and efficacy of NPs that would facilitate their approval by regulatory authorities for clinical use.

Toxicity prediction of nanoparticles using machine learning approaches

Nanoparticle toxicity analysis is critical for evaluating the safety of nanomaterials due to their potential harm to the biological system. However, traditional experimental methods for evaluating nanoparticle toxicity are expensive and time-consuming. As an alternative approach, machine learning offers a solution for predicting cellular responses to nanoparticles. This study focuses on developing ML models for nanoparticle toxicity prediction. The training dataset used for building these models includes the physicochemical properties of nanoparticles, exposure conditions, and cellular responses of different cell lines. The impact of each parameter on cell death was assessed using the Gini index. Five classifiers, namely Decision Tree, Random Forest, Support Vector Machine, Naïve Bayes, and Artificial Neural Network, were employed to predict toxicity. The models' performance was compared based on accuracy, sensitivity, specificity, area under the curve, F measure, K-fold validation, and classification error. The Gini index indicated that cell line, exposure dose, and tissue are the most influential factors in cell death. Among the models tested, Random Forest exhibited the highest performance in the given dataset. Other models demonstrated lower performance compared to Random Forest. Researchers can utilize the Random Forest model to predict nanoparticle toxicity, resulting in cost and time savings for toxicity analysis.

Influence of zinc oxide nanoparticles (ZnO NPs) on the hemocyte count and hemocyte-mediated immune responses of the Greater Wax Moth Galleria mellonella (Lepidoptera: Pyralidae)

In this study, we examined the effects of different doses (100, 500, 1000, 3000, and 5000 ppm) of zinc oxide nanoparticles (ZnO NPs) on the total hemocyte count and hemocyte-mediated immune responses of the Greater Wax Moth Galleria mellonella (Lepidoptera: Pyralidae). The results showed that NPs caused a decrease in hemocyte count at 1000, 3000, and 5000 ppm doses. To investigate the effects of ZnO NPs on the encapsulation and melanization response of G. mellonella, the pre-dyed Sephadex chromatography beads were injected into the hemolymph of each last-instar larva. Larvae were dissected in the 4th and 24th hours after the injection. The level of the encapsulation response and melanization status around the beads were determined under microscopy. The analyses of the beads injected into the insects as encapsulation targets revealed that the number of weakly encapsulated beads increased significantly at 100, 1000, 3000, and 5000 ppm doses when compared to the control group after a short (4-h) post-injection. The number of melanized beads increased significantly at 100, 1000, and 3000 ppm doses in comparison to the control group after the short (4-h) post-injection. Finally, the number of melanized beads decreased significantly at 1000 and 5000 ppm doses when compared to the control group after the long-term (24-h) post-injection.

Nanomedicine-fortified cosmeceutical serums for the mitigation of psoriasis and acne

Cosmetics have a long history of use for regenerative and therapeutic purposes that are appealing to both genders. The untapped potential of nanotechnology in cosmeceuticals promises enhanced efficacy and addresses the issues associated with conventional cosmetics. In the field of cosmetics, the incorporation of nanomedicine using various nanocarriers such as vesicle and solid lipid nanoparticles significantly enhances product effectiveness and promotes satisfaction, especially in tackling prevalent skin diseases. Moreover, vesicle-fortified serum is known for high skin absorption with the capacity to incorporate and deliver various therapeutics. Additionally, nano-embedded serum-based cosmeceuticals hold promise for treating various skin disorders, including acne and psoriasis, heralding potential therapeutic advancements. This review explores diverse nanotechnology-based approaches for delivering cosmetics with maximum benefits.

Intraperitoneal hepato-renal toxicity of zinc oxide and nickel oxide nanoparticles in male rats: biochemical, hematological and histopathological studies

In recent years, zinc oxide (ZnO) and nickel oxide (NiO) nanoparticles (NPs) have become more prevalent in commercial and industrial products. However, questions have been raised regarding their potential harm to human health. Limited studies have been conducted on their intraperitoneal toxicity in rats, and their co-exposure effects remain uncertain. Therefore, this study aimed to investigate some biological responses induced by a single intraperitoneal injection of ZnO-NPs (200 mg/kg) and/or NiO-NPs (50 mg/kg) in rats over time intervals. Blood and organ samples were collected from 36 male rats for hematological, biochemical, oxidative stress, and histological analysis. Results showed that the administration of NPs reduced the body and organ weights as well as red blood cell (RBC) indices and altered white blood cell (WBC) and platelet (PLT) counts. The experimental groups exhibited elevated levels of aspartate aminotransferase (AST), alanine transaminase (ALT), creatinine (CREA), urea, lipid profile, glucose (GLU), total protein (TP), albumin (ALB) and malondialdehyde (MDA), and decreased uric acid (UA), superoxide dismutase (SOD), and glutathione (GSH). Histological observations also revealed architectural damages in liver and kidneys. These alterations were time-dependent and varied in their degree of toxicity. Co-exposure of NPs initially lessened the damage but increased it afterwards compared to individual exposure. In conclusion, intraperitoneal injection of ZnO-NPs and/or NiO-NPs alters biological processes and induces oxidative stress in rats' liver and kidneys in a time-dependent manner, with NiO-NPs being more potent than ZnO-NPs. Furthermore, co-exposed NPs initially appeared to be antagonistic to one another while further aiming toward synergism.

Nanoparticle-Based Delivery Systems for Vaccines

Vaccination is still the most cost-effective way to combat infectious illnesses. Conventional vaccinations may have low immunogenicity and, in most situations, only provide partial protection. A new class of nanoparticle-based vaccinations has shown considerable promise in addressing the majority of the shortcomings of traditional and subunit vaccines. This is due to recent breakthroughs in chemical and biological engineering, which allow for the exact regulation of nanoparticle size, shape, functionality, and surface characteristics, resulting in improved antigen presentation and robust immunogenicity. A blend of physicochemical, immunological, and toxicological experiments can be used to accurately characterize nanovaccines. This narrative review will provide an overview of the current scenario of the nanovaccine.

An overview of synthesis, characterization, applications and associated adverse effects of bioactive nanoparticles

A particle with a diameter ranging from 1 to 100 nm is considered a nanoparticle (NP). Owing to their small size and high surface area, NPs possess unique physical, chemical and biological properties as compared to their bulkier counterparts. This paper describes various physico-chemical as well as green methods that can be used to synthesize different types of NPs including carbon-based, ceramic, metal, semiconductor, polymeric and lipid-based NPs. These methods can be categorized into either top-down or bottom-up approaches. Electron microscopy, atomic force microscopy, dynamic light scattering, X-ray diffraction, zeta-potential instrument, liquid chromatography-mass spectrometry, fourier transform infrared spectroscopy and thermogravimetric analysis are the techniques discussed in the characterization of NPs. This review provides an insight into the extraordinary properties of NPs that have opened the doors for endless biomedical applications like drug delivery, photo-ablation therapy, biosensors, bio-imaging and hyperthermia. In addition, NPs are also involved in improving crop growth, making protective clothing, cosmetics and energy reserves. This review also specifies adverse health effects associated with NPs such as hepatotoxicity, genotoxicity, neurotoxicity, etc., and inhibitory effects on plant growth and aquatic life. Further, in-vitro toxicity assessment assays for cell proliferation, apoptosis, necrosis and oxidative stress, as well as in-vivo toxicity assessment like biodistribution, clearance, hematological, serological and histological studies, are discussed here. Lastly, the authors have mentioned various measures that can be adopted to minimize the toxicity associated with NPs such as green synthesis, use of stabilizers, gene gun, polymer shell, microneedle capsule, etc.

Fabrication and Characterization of Submicron-Scale Bovine Hydroxyapatite: A Top-Down Approach for a Natural Biomaterial

Submicron hydroxyapatite has been reported to have beneficial effects in bone tissue engineering. This study aimed to fabricate submicron-scale bovine hydroxyapatite (BHA) using the high-energy dry ball milling method. Bovine cortical bone was pretreated and calcined to produce BHA powder scaled in microns. BHA was used to fabricate submicron BHA with milling treatment for 3, 6, and 9 h and was characterized by using dynamic light scattering, scanning electron microscope connected with energy dispersive X-Ray spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffractometry to obtain its particle size, calcium-to-phosphorus (Ca/P) ratio, functional chemical group, and XRD peaks and crystallinity. Results showed that the particle size of BHA had a wide distribution range, with peaks from ~5 to ~10 µm. Milling treatment for 3, 6, and 9 h successfully gradually reduced the particle size of BHA to a submicron scale. The milled BHA's hydrodynamic size was significantly smaller compared to unmilled BHA. Milling treatment reduced the crystallinity of BHA. However, the treatment did not affect other characteristics; unmilled and milled BHA was shaped hexagonally, had carbonate and phosphate substitution groups, and the Ca/P ratio ranged from 1.48 to 1.68. In conclusion, the fabrication of submicron-scale BHA was successfully conducted using a high-energy dry ball milling method. The milling treatment did not affect the natural characteristics of BHA. Thus, the submicron-scale BHA may be potentially useful as a biomaterial for bone grafts.

Nanocarriers as Active Ingredients Enhancers in the Cosmetic Industry-The European and North America Regulation Challenges

“Flawless skin is the most universally desired human feature” is an iconic statement by Desmond Morris. Skin indicates one´s health and is so important that it affects a person’s emotional and psychological behavior, these facts having propelled the development of the cosmetics industry. It is estimated that in 2023, this industry will achieve more than 800 billion dollars. This boost is due to the development of new cosmetic formulations based on nanotechnology. Nanocarriers have been able to solve problems related to active ingredients regarding their solubility, poor stability, and release. Even though nanocarriers have evident benefits, they also present some problems related to the high cost, low shelf life, and toxicity. Regulation and legislation are two controversial topics regarding the use of nanotechnology in the field of cosmetics. In this area, the U.S. FDA has taken the lead and recommended several biosafety studies and post-market safety evaluations. The lack of a global definition that identifies nanomaterials as a cosmetic ingredient is a hindrance to the development of global legislation. In the EU, the legislation regarding the biosafety of nanomaterials in cosmetics is stricter. “The cost is not the only important issue, safety and the application of alternative testing methods for toxicity are of crucial importance as well”.

Effect of Nanostructures on the Properties of Glass Ionomer Dental Restoratives/Cements: A Comprehensive Narrative Review

Overall perspective of nanotechnology and reinforcement of dental biomaterials by nanoparticles has been reported in the literature. However, the literature regarding the reinforcement of dental biomaterials after incorporating various nanostructures is sparse. The present review addresses current developments of glass ionomer cements (GICs) after incorporating various metallic, polymeric, inorganic and carbon-based nanostructures. In addition, types, applications, and implications of various nanostructures incorporated in GICs are discussed. Most of the attempts by researchers are based on the laboratory-based studies; hence, it warrants long-term clinical trials to aid the development of suitable materials for the load bearing posterior dentition. Nevertheless, a few meaningful conclusions are drawn from this substantial piece of work; they are as follows: (1) most of the nanostructures are likely to enhance the mechanical strength of GICs; (2) certain nanostructures improve the antibacterial activity of GICs against the cariogenic bacteria; (3) clinical translation of these promising outcomes are completely missing, and (4) the nanostructured modified GICs could perform better than their conventional counterparts in the load bearing posterior dentition.

Mechanism of action and cellular responses of HEK293 cells on challenge with zwitterionic carbon dots

Carbon, an extremely versatile element has great demand in the field of nanoscience. Carbon-based nanostructures are exponentially increased due to its wide range of applications in biotechnological and environmental approaches; hence, its safety assessment is of greater concern. In the present study, high quantum yielding zwitterionic carbon dots were synthesized, characterized and its safety assessment at different concentration ranges (50-1600 μgmL^-1) on HEK 293 cells was carried out. Cellular, mitochondrial, lysosomal integrity and ROS generation were assessed using specific fluorochromes.The key cellular event apoptosis was assessed by annexinpropidium iodide staining using imaging flow cytometry. Moreover, the mRNA levels of the apoptotic genes were determined by real-time PCR. The results revealed that the cell viability assays (MTT, NR) and mitochondrial membrane potential were altered on exposure to a higher concentration of zwitterionic CDs for 24 h. Also, annexinpropidiumiodidestaining exhibited an increased percentage of apoptotic cells upon exposure to zwitterionic CDs at higher concentrations. Further, apoptosis was confirmed by significantlyincreased expression of pro-apoptotic gene (Bax) together with decreased expression of Bcl-2/Bax ratio. Collectively, this study suggests that zwitterionic CDs induce apoptosis in HEK 293 at higher concentration and the safe range for its intended application is found to be 50-200 μg/mL.

Multifunctional and stimuli-responsive nanocarriers for targeted therapeutic delivery

INTRODUCTION

Nanocarrier-based delivery systems offer multiple benefits to overcome limitations of the traditional drug dosage forms, such as protection of the drug, enhanced bioavailability, targeted delivery to disease site, etc. Nanocarriers have exhibited tremendous successes in targeted delivery of therapeutics to the desired tissues and cells with improved bioavailability, high drug loading capacity, enhanced intracellular delivery, and better therapeutic effect. A specific design of stimuli-responsive nanocarriers allows for changing their structural and physicochemical properties in response to exogenous and endogenous stimuli. These nanocarriers show a promise in site specific controlled release of therapeutics under certain physiological conditions or external stimuli.

AREAS COVERED

This review highlights recent progresses on the multifunctional and stimuli-sensitive nanocarriers for targeted therapeutic drug delivery applications.

EXPERT OPINION

The progress from single functional to multifunctional nanocarriers has shown tremendous potential for targeted delivery of therapeutics. On our opinion, the future of targeted delivery of drugs, nucleic acids, and other substances belongs to the site-targeted multifunctional and stimuli-based nanoparticles with controlled release. Targeting of nanocarriers to the disease site enhance the efficacy of the treatment by delivering more therapeutics specifically to the affected cells and substantially limiting adverse side effects upon healthy organs, tissues, and cells.

Current Approaches and Techniques in Physiologically Based Pharmacokinetic (PBPK) Modelling of Nanomaterials

There have been efforts to develop physiologically based pharmacokinetic (PBPK) models for nanomaterials (NMs). Since NMs have quite different kinetic behaviors, the applicability of the approaches and techniques that are utilized in current PBPK models for NMs is warranted. Most PBPK models simulate a size-independent endocytosis from tissues or blood. In the lungs, dosimetry and the air-liquid interface (ALI) models have sometimes been used to estimate NM deposition and translocation into the circulatory system. In the gastrointestinal (GI) tract, kinetics data are needed for mechanistic understanding of NM behavior as well as their absorption through GI mucus and their subsequent hepatobiliary excretion into feces. Following absorption, permeability (P_t) and partition coefficients (PCs) are needed to simulate partitioning from the circulatory system into various organs. Furthermore, mechanistic modelling of organ- and species-specific NM corona formation is in its infancy. More recently, some PBPK models have included the mononuclear phagocyte system (MPS). Most notably, dissolution, a key elimination process for NMs, is only empirically added in some PBPK models. Nevertheless, despite the many challenges still present, there have been great advances in the development and application of PBPK models for hazard assessment and risk assessment of NMs.

Role of Beetroot (Beta vulgaris) Juice on Chronic Nanotoxicity of Silver Nanoparticle-Induced Hepatotoxicity in Male Rats

Introduction

Nanoparticles are at the forefront of rapidly developing nanotechnology and have gained much attention for their application as an effective drug delivery system and as a mediated therapeutic agent for cancer. However, the cytotoxicity of nanoparticles is still relatively unknown and, therefore, additional study is required in order to elucidate the potential toxicity of these nanoparticles on cells.

Materials and Methods

Thus, the following work aimed to investigate the capability of Beta vulgaris (beetroot) water extract (BWE; 200 mg/kg) to protect hepatic tissue following silver nanoparticles (AgNPs; 80 mg/kg; >100 nm) intoxication in male rats.

Results

AgNPs-intoxication elevated the liver function markers – including serum transaminases and alkaline phosphatase activities – and decreased serum levels of albumin and total proteins, in addition to disturbing the oxidation homeostasis. This is evidenced by the increased lipid peroxidation, the depleted glutathione, and the suppressed activity of superoxide dismutase and catalase. In addition, an apoptotic reaction was observed following AgNPs treatment, as indicated by the up-regulation of p53 and down-regulating Bcl-2 expressions, examined by the immunohistochemistry method. Furthermore, AgNPs exhibited a marked elevation in liver DNA damage that was indicated by an increase in tail length, tail DNA% and tail movement. However, BWE eliminated the biochemical and histological alterations, reflecting its hepatoprotection effect in response to AgNPs.

Discussion

Collectively, the present data suggest that BWE could be used following AgNPs as a potential therapeutic intervention to minimize AgNPs-induced liver toxicity.

Comparative study of toxicological assessment of yttrium oxide nano- and microparticles in Wistar rats after 28 days of repeated oral administration

Despite their enormous advantages, nanoparticles (NPs) have elicited disquiet over their safety. Among the numerous NPs, yttrium oxide (Y2O3) NPs are utilised in many applications. However, knowledge about their toxicity is limited, and it is imperative to investigate their potential adverse effects. Therefore, this study explored the effect of 28 days of repeated oral exposure of Wistar rats to 30, 120 and 480 mg/kg body weight (bw) per day of Y2O3 NPs and microparticles (MPs). Before initiation of the study, characterisation of the particles by transmission electron microscopy, dynamic light scattering, Brunauer-Emmett-Teller and laser Doppler velocimetry was undertaken. Genotoxicity was evaluated using the comet and micronucleus (MN) assays. Biochemical markers aspartate transaminase, alanine transaminase, alkaline phosphatase, malondialdehyde, superoxide dismutase, reduced glutathione, catalase and lactate dehydrogenase in serum, liver and kidney were determined. Bioaccumulation of the particles was analysed by inductively coupled plasma optical emission spectrometry. The results of the comet and MN assays showed significant differences between the control and groups treated with 120 and 480 mg/kg bw/day Y2O3 NPs. Significant biochemical alterations were also observed at 120 and 480 mg/kg bw/day. Haematological and histopathological changes were documented. Yttrium (Y) biodistribution was detected in liver, kidney, blood, intestine, lungs, spleen, heart and brain in a dose- and the organ-dependent manner in both the particles. Further, the highest levels of Y were found in the liver and the lowest in the brain of the treated rats. More of the Y from NPs was excreted in the urine than in the faeces. Furthermore, NP-treated rats exhibited much higher absorption and tissue accumulation. These interpretations furnish rudimentary data of the apparent genotoxicity of NPs and MPs of Y2O3 as well as the biodistribution of Y. A no-observed adverse effect level of 30 mg/kg bw/day was found after oral exposure of rats to Y2O3 NPs.

Topical Minoxidil-Loaded Nanotechnology Strategies for Alopecia

Androgenetic alopecia (AGA) is a multifactorial and age-related condition characterized by substantial hair loss affecting both men and women. Conventional treatments include the use of topical minoxidil (MNX) formulations to stimulate hair growth and restore hair condition. However, those treatments are associated with limited performance and a lack of tolerability and compliance due to the emergence of adverse effects. Considering that the development of nanotechnology-based formulations as hair loss therapeutic strategies has been clearly growing, topical MNX delivery by means of these innovative formulations is known to enhance MNX skin permeation and depot formation into hair follicles, allowing for MNX-controlled release, increased MNX skin bioavailability and enhanced therapeutic efficacy with minimal adverse effects. This review highlights the potential of nanotechnology-based MNX delivery formulations for improved hair loss therapeutics, including a thorough assessment of their in vitro and in vivo performances, as well as regulatory and nanosafety considerations.

Nanoparticle-based vaccines

Infectious diseases are the tip of the iceberg in the economic burden of the developing countries, due to the resistance of the pathogens to antibiotics and the lack of vaccines. The vaccines have become a big challenge in the last decades, where the attention has been focused on scientific challenges such as new vaccine development and adjuvants or delivery systems. The classical vaccines were developed from live-attenuated or killed organisms, such as influenza, smallpox, and BCG, as well as subunits such as Hepatitis B. The attenuated vaccines carry the risk of regaining their pathogenicity under immunosuppression conditions. The development of subunit vaccines without risk are considered as an essential need in combination with adequate delivery systems to obtain desired cell and humoral immune responses against infectious diseases. In the last decades, the use of nanoparticles as a delivery system in vaccines has received special attention to improve vaccine efficacy. These nanoparticles could be composed of lipids, metal and nonmetal inorganics, several polymers, and virus-like particles, which have been tested in research; some of them have already been approved for human and animal use. The characteristics of the nanoparticles have allowed targeting desired antigen-presenting cells to improve immunization strategies to induce protection. The main characteristics of the nanoparticles are to protect the antigens from early proteolytic degradation, control antigen release, and help antigen uptake and processing by antigen-presenting cells, and they should be safe for human and veterinary use. In addition, the nanoparticles could be modified in their physicochemical properties to target specific cells and improve vaccine efficacy. This chapter focuses on the nanoparticle-based vaccine formulations and the approaches used to realize efficient delivery of vaccines in order to induce host protective immunity against infectious diseases.

A health concern regarding the protein corona, aggregation and disaggregation

Nanoparticle (NP)-protein complexes exhibit the "correct identity" of NP in biological media. Therefore, protein-NP interactions should be closely explored to understand and modulate the nature of NPs in medical implementations. This review focuses mainly on the physicochemical parameters such as dimension, surface chemistry, morphology of NPs, and influence of pH on the formation of protein corona and conformational changes of adsorbed proteins by different kinds of techniques. Also, the impact of protein corona on the colloidal stability of NPs is discussed. Uncontrolled protein attachment on NPs may bring unwanted impacts such as protein denaturation and aggregation. In contrast, controlled protein adsorption by optimal concentration, size, pH, and surface modification of NPs may result in potential implementation of NPs as therapeutic agents especially for disaggregation of amyloid fibrils. Also, the effect of NPs-protein corona on reducing the cytotoxicity and clinical implications such as drug delivery, cancer therapy, imaging and diagnosis will be discussed. Validated correlative physicochemical parameters for NP-protein corona formation frequently derived from protein corona fingerprints of NPs which are more valid than the parameters obtained only on the base of NP features. This review may provide useful information regarding the potency as well as the adverse effects of NPs to predict their behavior in vivo.

Fluorescent Nanoparticles for the Guided Surgery of Ovarian Peritoneal Carcinomatosis

Complete surgical resection is the ideal cure for ovarian peritoneal carcinomatosis, but remains challenging. Fluorescent guided surgery can be a promising approach for precise cytoreduction when appropriate fluorophore is used. In the presence paper, we review already developed near- and short-wave infrared fluorescent nanoparticles, which are currently under investigation for peritoneal carcinomatosis fluorescence imaging. We also highlight the main ways to improve the safety of nanoparticles, for fulfilling prerequisites of clinical application.

Polyphenol nanoformulations for cancer therapy: experimental evidence and clinical perspective

Cancer is defined as the abnormal cell growth that can cause life-threatening malignancies with high financial costs for patients as well as the health care system. Natural polyphenols have long been used for the prevention and treatment of several disorders due to their antioxidant, anti-inflammatory, cytotoxic, antineoplastic, and immunomodulatory effects discussed in the literature; thus, these phytochemicals are potentially able to act as chemopreventive and chemotherapeutic agents in different types of cancer. One of the problems regarding the use of polyphenolic compounds is their low bioavailability. Different types of formulations have been designed for the improvement of bioavailability of these compounds, nanonization being one of the most notable approaches among them. This study aimed to review current data on the nanoformulations of natural polyphenols as chemopreventive and chemotherapeutic agents and to discuss their molecular anticancer mechanisms of action. Nanoformulations of natural polyphenols as bioactive agents, including resveratrol, curcumin, quercetin, epigallocatechin-3-gallate, chrysin, baicalein, luteolin, honokiol, silibinin, and coumarin derivatives, in a dose-dependent manner, result in better efficacy for the prevention and treatment of cancer. The impact of nanoformulation methods for these natural agents on tumor cells has gained wider attention due to improvement in targeted therapy and bioavailability, as well as enhancement of stability. Today, several nanoformulations are designed for delivery of polyphenolic compounds, including nanosuspensions, solid lipid nanoparticles, liposomes, gold nanoparticles, and polymeric nanoparticles, which have resulted in better antineoplastic activity, higher intracellular concentration of polyphenols, slow and sustained release of the drugs, and improvement of proapoptotic activity against tumor cells. To conclude, natural polyphenols demonstrate remarkable anticancer potential in pharmacotherapy; however, the obstacles in terms of their bioavailability in and toxicity to normal cells, as well as targeted drug delivery to malignant cells, can be overcome using nanoformulation-based technologies, which optimize the bioefficacy of these natural drugs.

Opportunities and obstacles to the development of nanopharmaceuticals for human use

Pharmaceutical nanotechnology has generated breakthrough developments in improving health care and human life from its emergence. The biomaterials employed mainly aim at improving drug delivery systems, imaging and diagnostic technologies while the nanoscale materials are in widespread use in other industries such as electronics and optics. Such advancement may revolutionize the drug development and therapy with new and more efficient treatments. Although, nanotechnology assists humankind in improving its well being, it has certain limitations that entail thorough investigation by the regulatory and scientific authorities. To address concerns regarding the safety and toxicity profile of the nanopharmaceuticals, we have reviewed the challenges and solutions of nanopharmaceuticals use in human health and the related health risks. In this regard, regulatory and scientific bodies such as countries' Food and Drug Administration (FDA), Organization for Economic Co-operation and Development (OECD), European Medicine Agency (EMA), Environmental Protection Agency (EPA), National Institute for Occupational Safety and Health (NIOSH), and World Health Organization (WHO) can participate in developing and reinforcing safety measures and regulatory frameworks to insure the public health. The regulatory authorities may enforce the nanopharmaceutical industries to conduct comprehensive toxicity tests and monitor the adverse drug reaction reports in close collaboration with the scientific community to act accordingly and inform the public as the implementation of the strategy. Nanopharmaceuticals have tremendous potential for human use as therapeutic or diagnostic agents. But their toxicity profile should be well addressed and the respective regulatory framework developed and reinforced by the authorities.

Toxicity and efficacy of CdO nanostructures on the MDCK and Caki-2 cells

This article reports the toxicological effects of synthesized cadmium oxide (CdO) nanostructures via a simple green route using a Polygala tenuifolia root extract on normal and renal tumor cells. First, the formation of cadmium oxide nanostructures were confirmed structurally by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy (XPS). The powder was crystallized in a cubic structure with a space group of Fm-3m. The mean crystallize size was approximately 40 and 44nm from the Scherrer and size-strain plots, respectively. The surface states of the cadmium oxide nanostructure using the O 1s and Cd 3d spectra were analyzed by XPS. Transmission electron microscopy showed that the simple green route resulted in various morphologies of synthesized cadmium oxide, such as trigonal-, tetrahedron-, and sheet-like structures. Finally, the toxic effects of the cadmium oxide nanostructures on Madin-Darby canine kidney epithelial cells (MDCK cells), as well as the human renal cancer cell line (Caki-2 cells) were investigated using a SRB assay and two-color flow cytometry analysis. The cadmium oxide nanostructures showed significant cell growth inhibition in normal and also tumor cells in a dose-dependent manner. On the other hand, the inhibition was higher in the cancer cells compared to the normal cells.

Biochemical and molecular evidences on the protection by magnesium oxide nanoparticles of chlorpyrifos-induced apoptosis in human lymphocytes

Background:

Chlorpyrifos (CP) is one of the most widely used organophosphate (OP) insecticides in agricultural and residential pest control with its attendant adverse health effect. In the present study, it is proposed to investigate the possible modulatory role of magnesium oxide nanoparticles (MgO NPs) against CP-induced toxicity in human lymphocytes and determine the mechanisms lying behind this protection by viability and biochemical assays.

Materials and Methods:

Isolated lymphocytes were exposed to 12 μg/mL CP either alone or in combination with different concentrations of MgO NPs (0.1 μg/mL, 1 μg/mL, 10 μg/mL, and 100 μg/mL). After a 3-day incubation, the viability and oxidative stress markers including cellular mitochondrial activity, caspase-3 and -9 activities, total antioxidant power, lipid peroxidation, and myeloperoxidase (MPO) activity were measured. Also, the levels of tumor necrosis factor-α (TNF-α) as inflammatory index, along with acetylcholinesterase (AChE) activity were measured. Statistical differences were determined using one-way analysis of variance (ANOVA) and Dunnett's multiple comparison tests.

Results:

It is indicated that CP-exposed lymphocytes treated with MgO NPs resulted in a substantial reduction in the pace of mortality as well as the stages of oxidative stress in a dose-dependent manner. Also, MgO NPs (100 μg/mL) meaningfully restored CP-induced increase of TNF-α (P < 0.001) and decrease of AChE activity (P < 0.001) and were capable of preventing CP-treated human lymphocytes from apoptosis (P < 0.001).

Conclusion:

Our results demonstrate that MgO NPs in approximate 100 nm diameter not only make cells resistant to the toxic properties of CP but also attenuate toxic effects of CP, which is demonstrating the potential of MgO NPs to be applied in future immune deficiency therapeutic strategies.

A systematic review on the role of environmental toxicants in stem cells aging

Stem cells are an important target for environmental toxicants. As they are the main source for replenishing of organs in the body, any changes in their normal function could affect the regenerative potential of organs, leading to the appearance of age-related disease and acceleration of the aging process. Environmental toxicants could exert their adverse effect on stem cell function via multiple cellular and molecular mechanisms, resulting in changes in the stem cell differentiation fate and cell transformation, and reduced self-renewal capacity, as well as induction of stress-induced cellular senescence. The present review focuses on the effect of environmental toxicants on stem cell function associated with the aging process. We categorized environmental toxicants according to their preferred molecular mechanism of action on stem cells, including changes in genomic, epigenomic, and proteomic levels and enhancing oxidative stress. Pesticides, tobacco smoke, radiation and heavy metals are well-studied toxicants that cause stem cell dysfunction via induction of oxidative stress. Transgenerational epigenetic changes are the most important effects of a variety of toxicants on germ cells and embryos that are heritable and could affect health in the next several generations. A better understanding of the underlying mechanisms of toxicant-induced stem cell aging will help us to develop therapeutic intervention strategies against environmental aging. Meanwhile, more efforts are required to find the direct in vivo relationship between adverse effect of environmental toxicants and stem cell aging, leading to organismal aging.

Toxicity of Nanoparticles and an Overview of Current Experimental Models

Nanotechnology is a rapidly growing field having potential applications in many areas. Nanoparticles (NPs) have been studied for cell toxicity, immunotoxicity, and genotoxicity. Tetrazolium-based assays such as MTT, MTS, and WST-1 are used to determine cell viability. Cell inflammatory response induced by NPs is checked by measuring inflammatory biomarkers, such as IL-8, IL-6, and tumor necrosis factor, using ELISA. Lactate dehydrogenase (LDH) assay is used for cell membrane integrity. Different types of cell cultures, including cancer cell lines have been employed as in vitro toxicity models. It has been generally agreed that NPs interfere with either assay materials or with detection systems. So far, toxicity data generated by employing such models are conflicting and inconsistent. Therefore, on the basis of available experimental models, it may be difficult to judge and list some of the more valuable NPs as more toxic to biological systems and vice versa. Considering the potential applications of NPs in many fields and the growing apprehensions of FDA about the toxic potential of nanoproducts, it is the need of the hour to look for new internationally agreed free of bias toxicological models by focusing more on in vivo studies.

Zinc oxide nanoparticles reduce apoptosis and oxidative stress values in isolated rat pancreatic islets

Although toxic effects of zinc oxide nanoparticles (ZnO NPs) have been previously studied, there are still controversies in terms of dose, size, shape, and affecting cells. By such a perspective, in this study, small size of ZnO NPs with a diameter of 10 nm at low concentrations was studied for any effect on the viability and function of isolated rat pancreatic islets. Islets of Langerhans were isolated and assessed for viability, functionality (insulin secretion), cytosolic reactive oxygen species (ROS), and apoptosis by flow cytometry. The LC50 of ZnO NPs was found at 1,400 ng/mL at the first phase of the study. A meaningful increase in viability of islets and insulin secretion in basal and even stimulated concentrations of glucose was found by ZnO NPs (70 ng/mL) with p < 0.001 and p < 0.05, respectively. Likewise, ZnO NPs in 70 ng/mL concentration decreased cytosolic ROS generation (p < 0.05). In the meantime, the percentage of early stage of apoptotic cells dropped down to 17 % (from 29 % of control). These results for the first time confirm that ZnO NPs are not only safe when used at dose of 70 ng/mL but also improve viability and function of pancreatic islets and meanwhile reduce oxidative stress and prevent cells from entering the apoptotic phase.

Toxicity of nanomaterials; an undermined issue

Nanomaterials are employed in extensive variety of commercial products such as electronic components, cosmetics, food, sports equipment, biomedical applications, and medicine. With the increasing utilization of engineered nanomaterials, the potential exposure of human to nanoparticles is rapidly increasing. Nowadays when new nanomaterials with new applications are introduced, mostly good and positive effects are mentioned whereas possible hazards arising from nanosize of the compounds are undermined. Toxicology studies of nanomaterials demonstrate some adverse effects in some human organs such as central nerve system, immune system, and lung. There is lack of complete information about human toxicity and environmental waste of nanomaterials. We aimed to highlight current toxicological concerns of potentially useful nanomaterials which are now used in pharmaceutical and biomedical sciences.

Safety concerns to application of graphene compounds in pharmacy and medicine

Graphene, the new allotrope of carbon is a single layer of monocrystalline graphite with sp2 hybridized carbon atoms. This compound has received worldwide attention due to its extraordinary physical and chemical properties. Duo to the widespread application of geraphenes, concerns are raising about its environmental safety or the safety protocols for handling and waste of graphene-based materials. The generation of reactive free radicals, adsorption of important biomolecules, and physical toxicity of graphene also matter. Hereby we criticize the concerns on the toxicity of graphenes to provide some perspective on the potential hazards of future development in graphene-based biomaterials.

Evaluation of in vitro toxicity of peptide (N-acetyl-Leu-Gly-Leu-COOH)-substituted-β-cyclodextrin derivative, a novel drug carrier, in PC-12 cells

Background

Cyclodextrins (CDs) have been shown to improve physicochemical and biopharmaceutical properties of drugs when low solubility and low safety limit their use in the pharmaceutical field. Recently, a new amphiphilic peptide-substituted-β-CD, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD (hepta-(N-acetyl-LGL)-β-CD), is developed which exhibited good solubility, strong inclusion ability and an appropriate average molecular weight. However, there is limited information available about its toxic effects. This study was designed to evaluate cytotoxic effects of the hepta-(N-acetyl-LGL)-β-CD (50, 200, 400, and 800 μg/ml) on rat pheochromocytoma PC-12 cells.

Results

A significant reduction of cell viability with IC₅₀ values of 1115.0 μg/ml, 762.4 μg/ml, and 464.9 μg/ml at 6, 12, and 24 h post-treatment, respectively, as well as increased lipid peroxide levels and DNA damage were observed.

Conclusions

In conclusion, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD exhibit significant toxic properties at high concentrations, probably through induction of oxidative stress and genotoxicity.

Preparation, characterization and optimization of sildenafil citrate loaded PLGA nanoparticles by statistical factorial design

BACKGROUND AND THE AIM OF THE STUDY

The objective of the present study was to formulate and optimize nanoparticles (NPs) of sildenafil-loaded poly (lactic-co-glycolic acid) (PLGA) by double emulsion solvent evaporation (DESE) method. The relationship between design factors and experimental data was evaluated using response surface methodology.

METHOD

A Box-Behnken design was made considering the mass ratio of drug to polymer (D/P), the volumetric proportion of the water to oil phase (W/O) and the concentration of polyvinyl alcohol (PVA) as the independent agents. PLGA-NPs were successfully prepared and the size (nm), entrapment efficiency (EE), drug loading (DL) and cumulative release of drug from NPs post 1 and 8 hrs were assessed as the responses.

RESULTS

The NPs were prepared in a spherical shape and the sizes range of 240 to 316 nm. The polydispersity index of size was lower than 0.5 and the EE (%) and DL (%) varied between 14-62% and 2-6%, respectively. The optimized formulation with a desirability factor of 0.9 was selected and characterized. This formulation demonstrated the particle size of 270 nm, EE of 55%, DL of 3.9% and cumulative drug release of 79% after 12 hrs. In vitro release studies showed a burst release at the initial stage followed by a sustained release of sildenafil from NPs up to 12 hrs. The release kinetic of the optimized formulation was fitted to Higuchi model.

CONCLUSIONS

Sildenafil citrate NPs with small particle size, lipophilic feature, high entrapment efficiency and good loading capacity is produced by this method. Characterization of optimum formulation, provided by an evaluation of experimental data, showed no significant difference between calculated and measured data.

Different biokinetics of nanomedicines linking to their toxicity; an overview

In spite of the extreme rise to the knowledge of nanotechnology in pharmaceutical sciences, there are currently limited experimental works studying the interactions between nanoparticles (NPs) and the biological system. Adjustment of size and surface area plays the main role in the reaction between NPs and cells leading to their increased entrance into cells through skin, gastrointestinal and respiratory system. Moreover, change in physicochemical reactivity of NPs causes them to interact with circulatory and cellular proteins differentially leading to the altered parameters of their biokinetics, including adsorption, distribution, translocation, transformation, and elimination. A direct relationship between the surface area, reactive oxygen species generating capability, and proinflammatory effects of NPs have been found in respiratory tract toxicity. Additionally, complement-mediated hypersensitivity reactions to liposomes and other lipid-based nanodrugs have been well defined. Inhalation studies of some NPs have confirmed the translocation of inhaled materials to extra pulmonary organs such as central nervous system (CNS) via olfactory neurons and induction of inflammatory response. Injectable uncoated NPs have a tendency to remain on the injection site while the poly ethanol glycol (PEG)-coated NPs can be notably drained from the injection site to get as far as the lymph nodes where they accumulate. This confirms the existence of channels within the extracellular matrix for NPs to move along. Furthermore, induction of DNA strand breaks and formation of micronuclei have been recorded for exposure to some NPs such as single-walled carbon nanotubes.

In the recent years, most of the studies have simply outlined better efficacy of nanodrugs, but few discussed their possible toxic reactions specially if used chronically. Therefore, we emphasize that this part of the nanoscience must not be undermined and toxicologists must be sensitive to set up suitable in vivo or in vitro toxicity models. A system for collecting data about the relationships between NPs’ structure-size-efficacy-toxicity (SSET) should be specified with special regard to portal of entry and target organ.