Toxicity Effects of Functionalized Quantum Dots, Gold and Polystyrene Nanoparticles on Target Aquatic Biological Models: A Review

Nose-to-brain drug delivery for the treatment of glioblastoma multiforme: nanotechnological interventions

Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumor with a short survival rate. Extensive research is underway for the last two decades to find an effective treatment for GBM but the tortuous pathophysiology, development of chemoresistance, and presence of BBB are the major challenges, prompting scientists to look for alternative targets and delivery strategies. Therefore, the nose to brain delivery emerged as an unorthodox and non-invasive route, which delivers the drug directly to the brain via the olfactory and trigeminal pathways and also bypasses the BBB and hepatic metabolism of the drug. However, mucociliary clearance, low administration volume, and less permeability of nasal mucosa are the obstacles retrenching the brain drug concentration. Thus, nanocarrier delivery through this route may conquer these limitations because of their unique surface characteristics and smaller size. In this review, we have emphasized the advantages and limitations of nanocarrier technologies such as polymeric, lipidic, inorganic, and miscellaneous nanoparticles used for nose-to-brain drug delivery against GBM in the past 10 years. Furthermore, recent advances, patents, and clinical trials are highlighted. However, most of these studies are in the early stages, so translating their outcomes into a marketed formulation would be a milestone in the better progression and survival of glioma patients.

Present and future of metal nanoparticles in tumor ablation therapy

Cancer is an important factor affecting the quality of human life as well as causing death. Tumor ablation therapy is a minimally invasive local treatment modality with unique advantages in treating tumors that are difficult to remove surgically. However, due to its physical and chemical characteristics and the limitation of equipment technology, ablation therapy cannot completely kill all tumor tissues and cells at one time; moreover, it inevitably damages some normal tissues in the surrounding area during the ablation process. Therefore, this technology cannot be the first-line treatment for tumors at present. Metal nanoparticles themselves have good thermal and electrical conductivity and unique optical and magnetic properties. The combination of metal nanoparticles with tumor ablation technology, on the one hand, can enhance the killing and inhibiting effect of ablation technology on tumors by expanding the ablation range; on the other hand, the ablation technology changes the physicochemical microenvironment such as temperature, electric field, optics, oxygen content and pH in tumor tissues. It helps to stimulate the degree of local drug release of nanoparticles and increase the local content of anti-tumor drugs, thus forming a synergistic therapeutic effect with tumor ablation. Recent studies have found that some specific ablation methods will stimulate the body's immune response while physically killing tumor tissues, generating a large number of immune cells to cause secondary killing of tumor tissues and cells, and with the assistance of metal nanoparticles loaded with immune drugs, the effect of this anti-tumor immunotherapy can be further enhanced. Therefore, the combination of metal nanoparticles and ablative therapy has broad research potential. This review covers common metallic nanoparticles used for ablative therapy and discusses in detail their characteristics, mechanisms of action, potential challenges, and prospects in the field of ablation.

Exploring the multifunctional roles of quantum dots for unlocking the future of biology and medicine

With recent advancements in nanomedicines and their associated research with biological fields, their translation into clinically-applicable products is still below promises. Quantum dots (QDs) have received immense research attention and investment in the four decades since their discovery. We explored the extensive biomedical applications of QDs, viz. Bio-imaging, drug research, drug delivery, immune assays, biosensors, gene therapy, diagnostics, their toxic effects, and bio-compatibility. We unravelled the possibility of using emerging data-driven methodologies (bigdata, artificial intelligence, machine learning, high-throughput experimentation, computational automation) as excellent sources for time, space, and complexity optimization. We also discussed ongoing clinical trials, related challenges, and the technical aspects that should be considered to improve the clinical fate of QDs and promising future research directions.

The influence of size and surface chemistry on the bioavailability, tissue distribution and toxicity of gold nanoparticles in zebrafish (Danio rerio)

Gold nanoparticles (AuNPs) are widely used in biomedicine and their specific properties including, size, geometrics, and surface coating, will affect their fate and behaviour in biological systems. These properties are well studied for their intended biological targets, but there is a lack of understanding on the mechanisms by which AuNPs interact in non-target organisms when they enter the environment. We investigated the effects of size and surface chemistry of AuNPs on their bioavailability, tissue distribution and potential toxicity using zebrafish (Danio rerio) as an experimental model. Larval zebrafish were exposed to fluorescently tagged AuNPs of different sizes (10-100 nm) and surface modifications (TNFα, NHS/PAMAM and PEG), and uptake, tissue distribution and depuration rates were measured using selective-plane illumination microscopy (SPIM). The gut and pronephric tubules were found to contain detectable levels of AuNPs, and the concentration-dependent accumulation was related to the particle size. Surface addition of PEG and TNFα appeared to enhance particle accumulation in the pronephric tubules compared to uncoated particles. Depuration studies showed a gradual removal of particles from the gut and pronephric tubules, although fluorescence indicating the presence of the AuNPs remained in the pronephros 96 h after exposure. Toxicity assessment using two transgenic zebrafish reporter lines, however, revealed no AuNP-related renal injury or cellular oxidative stress. Collectively, our data show that AuNPs used in medical applications across the size range 40-80 nm, are bioavailable to larval zebrafish and some may persist in renal tissue, although their presence did not result in measurable toxicity with respect to pronephric organ function or cellular oxidative stress for short term exposures.

Evolution of Detecting Early Onset of Alzheimer's Disease: From Neuroimaging to Optical Immunoassays

Alzheimer's disease (AD) is a pathological disorder defined by the symptoms of memory loss and deterioration of cognitive abilities over time. Although the etiology is complex, it is mainly associated with the accumulation of toxic amyloid-β peptide (Aβ) aggregates and tau protein-induced neurofibrillary tangles (NFTs). Even now, creating non-invasive, sensitive, specific, and cost-effective diagnostic methods for AD remains challenging. Over the past few decades, polymers, and nanomaterials (e.g., nanodiamonds, nanogold, quantum dots) have become attractive and practical tools in nanomedicine for diagnosis and treatment. This review focuses on current developments in sensing methods such as enzyme-linked immunosorbent assay (ELISA) and surface-enhanced Raman scattering (SERS) to boost the sensitivity in detecting related biomarkers for AD. In addition, optical analysis platforms such as ELISA and SERS have found increasing popularity among researchers due to their excellent sensitivity and specificity, which may go as low as the femtomolar range. While ELISA offers easy technological usage and high throughput, SERS has the advantages of improved mobility, simple electrical equipment integration, and lower cost. Both portable optical sensing techniques are highly superior in terms of sensitivity, specificity, human application, and practicality, enabling the early identification of AD biomarkers.

DNA-Immobilized Fluorescent Polystyrene Nanoparticles as Probes with Tunable Detection Limits

DNA-immobilized nanoparticle probes show high target specificity; thus, they are employed in various bioengineering and biomedicine applications. When the nanoparticles employed are dye-loaded polymer particles, the resulting probes have the additional benefit of biocompatibility and versatile surface properties. In this study, we construct DNA-immobilized fluorescent polystyrene (PS) nanoparticles through controlled surface reactions. PS nanoparticles with surface carboxyl groups are utilized, and amine-functionalized dye molecules and capture DNAs are covalently immobilized via a one-pot reaction. We show that the surface chemistry employed allows for quantitative control over the number of fluorescent dyes and DNA strands immobilized on the PS nanoparticle surfaces. The nanoparticles thus prepared are then used for DNA detection. The off state of the nanoprobe is achieved by hybridizing quencher-functionalized DNAs (Q-DNAs) to the capture DNAs immobilized on nanoparticle surfaces. Target-DNAs (T-DNAs) are detected by the displacement of the prehybridized Q-DNAs. The nanoprobes show successful detection of T-DNAs with high sequence specificity and long-term stability. They also show excellent detection sensitivity, and the detection limit can be tuned by adjusting the capture DNA-to-dye ratio.

The Antimicrobial Effect of Gold Quantum Dots and Femtosecond Laser Irradiation on the Growth Kinetics of Common Infectious Eye Pathogens: An In Vitro Study

We studied the antimicrobial effect of gold quantum dots (AuQDs), femtosecond laser irradiation, and the combined effect of laser irradiation and AuQD treatment against common infectious eye pathogens. The INSPIRE HF100 laser system (Spectra Physics) provided a femtosecond laser, which was pumped by a mode-locked femtosecond Ti: sapphire laser MAI TAI HP (Spectra Physics), while a Quanta-Ray nanosecond Nd: YAG laser (Spectra-Physics) was used to precisely synthesize 7.8, 8.7, and 11.6 nm spherical AuQDs. Then, the in vitro growth kinetics and growth rate analysis of E. coli, methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, and Candida albicans (treated with the AuQDs, femtosecond laser irradiation, or combined laser and AuQDs treatment) was measured. The biocompatibility of the AuQDs with the retinal epithelial cell lines (ARPE-19) and their toxicity to the cells was assayed. The results showed that (1) in vitro irradiation using a 159 J/cm² energy density obtained from the 400 nm femtosecond laser suppressed the growth of each of the five pathogens. (2) Similarly, treatment with the AuQDs was antimicrobial against the four bacteria. The AuQDs with an average size of 7.8 nm were more highly antimicrobial and biocompatible and were less cytotoxic than the larger AuQD sizes. (3) The combined femtosecond laser irradiation and AuQD treatment was more highly antimicrobial than each treatment alone. (4) The AuQD treatment did not impair the rate of wound closure in vitro. These findings suggest that combined femtosecond laser irradiation and AuQD treatment is significantly antimicrobial against Candida albicans, Gram-positive L. monocytogenes, S. aureus, and E. faecalis, as well as Gram-negative E. coli. The nontoxicity and biocompatibility of the AuQD particles tested suggest that this form of treatment may be clinically viable.

Semiconductor Quantum Dots as Target Analytes: Properties, Surface Chemistry and Detection

Since the discovery of Quantum Dots (QDs) by Alexey I. Ekimov in 1981, the interest of researchers in that particular type of nanomaterials (NMs) with unique optical and electrical properties has been increasing year by year. Thus, since 2009, the number of scientific articles published on this topic has not been less than a thousand a year. The increasing use of QDs due to their biomedical, pharmaceutical, biological, photovoltaics or computing applications, as well as many other high-tech uses such as for displays and solid-state lighting (SSL), has given rise to a considerable number of studies about its potential toxicity. However, there are a really low number of reported studies on the detection and quantification of QDs, and these include ICP–MS and electrochemical analysis, which are the most common quantification techniques employed for this purpose. The knowledge of chemical phenomena occurring on the surface of QDs is crucial for understanding the interactions of QDs with species dissolved in the dispersion medium, while it paves the way for a widespread use of chemosensors to facilitate its detection. Keeping in mind both human health and environmental risks of QDs as well as the scarcity of analytical techniques and methodological approaches for their detection, the adaptation of existing techniques and methods used with other NMs appears necessary. In order to provide a multidisciplinary perspective on QD detection, this review focused on three interrelated key aspects of QDs: properties, surface chemistry and detection.

Quantum dot synthesis from waste biomass and its applications in energy and bioremediation

Quantum dots (QDs) are getting special attention due to their commendable optical properties and applications. Conventional metal-based QDs have toxicity and non-biodegradability issues, thus it becomes necessary to search for renewable precursor molecules for QDs synthesis. In recent years, biomass-based carbon rich QDs (CQDs) have been introduced which are mainly synthesised via carbonization (pyrolysis and hydrothermal treatment). These CQDs offered higher photostability, biocompatibility, low-toxicity, and easy tunability for physicochemical properties. Exceptional optical properties become a point of attraction for its multifaceted applications in various sectors like fabrication of electrodes and solar cells, conversion of solar energy to electricity, detection of pollutants, designing biosensors, etc. In recent years, a lot of work has been done in this field. This article will summarize these advancements along in a special context to biomass-based QDs and their applications in energy and the environment.

Quantum dots based sensitive nanosensors for detection of antibiotics in natural products: A review

Residual antibiotics in food products originated from administration of the antibiotics to animals may be accumulated through food metabolism in the human body and endanger safety and health. Thus, developing a prompt and accurate way for detection of antibiotics is a crucial issue. The zero-dimensional fluorescent probes including metals based, carbon and graphene quantum dots (QDs), are highly sensitive materials to use for the detection of a wide range of antibiotics in natural products. These QDs demonstrate unique optical properties like tunable photoluminescence (PL) and excitation-wavelength dependent emission. This study investigates the trends related to carbon and metal based QDs preparation and modification, and their diverse detection application. We discuss the performance of QDs based sensors application in various detection systems such as photoluminescence, photoelectrochemical, chemiluminescence, electrochemiluminescence, colorimetric, as well as describing their working principles in several samples. The detecting mechanism of a QDs-based sensor is dependent on its properties and specific interactions with particular antibiotics. This review also tries to describe environmental application and future perspective of QDs for antibiotics detection.

Adaptation of a Bacterial Bioluminescent Assay to Monitor Bioeffects of Gold Nanoparticles

Our current study aimed to adapt a bioluminescent bacteria-based bioassay to monitor the bioeffects of gold nanoparticles (AuNPs). Luminous marine bacteria Photobacterium phosphoreum and AuNPs modified with polyvinylpyrrolidone were employed; low-concentration (≤10−3 g/L) bioeffects of AuNPs were studied. Bioluminescence intensity was used as an indicator of physiological activity in bacteria. Two additional methods were used: reactive oxygen species (ROS) content was estimated with a chemiluminescent luminol method, and bacterial size was monitored using electron microscopy. The bacterial bioluminescent response to AuNPs corresponded to the “hormesis” model and involved time-dependent bioluminescence activation, as well as a pronounced increase in the number of enlarged bacteria. We found negative correlations between the time courses of bioluminescence and the ROS content in bacterial suspensions, demonstrating the relationship between bioluminescence activation and bacterial ROS consumption. The combined effects of AuNPs and a beta-emitting radionuclide, tritium, revealed suppression of bacterial bioluminescent activity (as compared to their individual effects) and a reduced percentage of enlarged bacteria. Therefore, we demonstrated that our bacteria-based bioluminescence assay is an appropriate tool to study the bioeffects of AuNPs; the bioeffects can be further classified within a unified framework for rapid bioassessment.

Toxic effects of SiO2NPs in early embryogenesis of Xenopuslaevis

The exposure of organisms to the nanoparticulate is potentially hazardous, particularly when it occurs during embryogenesis. The effects of commercial SiO₂NPs in early development were studied, using Xenopus laevis as a model to investigate their possible future employment by means of the Frog Embryo Teratogenesis Assay-Xenopus test (FETAX). The SiO₂NPs did not change the survival but produced several abnormalities in developing embryos, in particular, the dorsal pigmentation, the cartilages of the head and branchial arches were modified; the encephalon, spinal cord and nerves are anomalous and the intestinal brush border show signs of suffering; these embryos are also bradycardic. In addition, the expression of genes involved in the early pathways of embryo development was modified. Treated embryos showed an increase of reactive oxygen species. This study suggests that SiO₂NPs are toxic but non-lethal and showed potential teratogenic effects in Xenopus. The latter may be due to their cellular accumulation and/or to the effect caused by the interaction of SiO₂NPs with cytoplasmic and/or nuclear components. ROS production could contribute to the observed effects. In conclusion, the data indicates that the use of SiO₂NPs requires close attention and further studies to better clarify their activity in animals, including humans.

Safe-by-Design part II: A strategy for balancing safety and functionality in the different stages of the innovation process

Manufactured nanomaterials have the potential to impact an exceedingly wide number of industries and markets ranging from energy storage, electronic and optical devices, light-weight construction to innovative medical approaches for diagnostics and therapy. In order to foster the development of safer nanomaterial-containing products, two main aspects are of major interest: their functional performance as well as their safety towards human health and the environment. In this paper a first proposal for a strategy is presented to link the functionality of nanomaterials with safety aspects. This strategy first combines information on the functionality and safety early during the innovation process and onwards, and then identifies Safe-by-Design (SbD) actions that allow for optimisation of both aspects throughout the innovation process. The strategy encompasses suggestions for the type of information needed to balance functionality and safety to support decision making in the innovation process. The applicability of the strategy is illustrated using a literature-based case study on carbon nanotube-based transparent conductive films. This is a first attempt to identify information that can be used for balancing functionality and safety in a structured way during innovation processes.

Novel Methods and Approaches for Safety Evaluation of Nanoparticle Formulations: A Focus Towards In Vitro Models and Adverse Outcome Pathways

Nanotoxicology is an emerging field employed in the assessment of unintentional hazardous effects produced by nanoparticles (NPs) impacting human health and the environment. The nanotoxicity affects the range between induction of cellular stress and cytotoxicity. The reasons so far reported for these toxicological effects are due to their variable sizes with high surface areas, shape, charge, and physicochemical properties, which upon interaction with the biological components may influence their functioning and result in adverse outcomes (AO). Thus, understanding the risk produced by these materials now is an important safety concern for the development of nanotechnology and nanomedicine. Since the time nanotoxicology has evolved, the methods employed have been majorly relied on in vitro cell-based evaluations, while these simple methods may not predict the complexity involved in preclinical and clinical conditions concerning pharmacokinetics, organ toxicity, and toxicities evidenced through multiple cellular levels. The safety profiles of nanoscale nanomaterials and nanoformulations in the delivery of drugs and therapeutic applications are of considerable concern. In addition, the safety assessment for new nanomedicine formulas lacks regulatory standards. Though the in vivo studies are greatly needed, the end parameters used for risk assessment are not predicting the possible toxic effects produced by various nanoformulations. On the other side, due to increased restrictions on animal usage and demand for the need for high-throughput assays, there is a need for developing and exploring novel methods to evaluate NPs safety concerns. The progress made in molecular biology and the availability of several modern techniques may offer novel and innovative methods to evaluate the toxicological behavior of different NPs by using single cells, cell population, and whole organisms. This review highlights the recent novel methods developed for the evaluation of the safety impacts of NPs and attempts to solve the problems that come with risk assessment. The relevance of investigating adverse outcome pathways (AOPs) in nanotoxicology has been stressed in particular.

Single and combined toxicity of amino-functionalized polystyrene nanoparticles with potassium dichromate and copper sulfate on brine shrimp Artemia franciscana larvae

The increasing use and disposal of plastics has become a persistent problem in the marine environment, calling for studies that refer to realistic scenarios to understand their effects on biota. Particularly, the understanding about the effects of co-exposure with nanoplastic particles and metals on aquatic organisms is still limited. The present work aimed to investigate the acute toxicity of amino-functionalized polystyrene nanoparticles (PS-NH₂; 50 nm) as proxy for nanoplastics on brine shrimp Artemia franciscana larvae under different culture conditions and at different stages of development, as well as the combined effect with two reference toxicants - potassium dichromate (K₂Cr₂O₇) and copper sulfate (CuSO₄). Nauplii (instar II or III larval stages) were exposed to different concentrations of PS-NH₂ (0.005 to 5 μg mL^-1) for up to 48 h, with or without agitation in order to mimic a more realistic environmental scenario. Larval mobility and PS-NH₂ accumulation were monitored under microscopy. PS-NH₂ alone showed toxicity only at the highest concentration tested (5 μg mL^-1) regardless the incubation method used (61.2 + 3.1% and 65.0 + 4.5% with and without agitation, respectively). Moreover, instar III stage was the most sensitive to PS-NH₂ exposure (38.2% immobility in 24 h of exposure; 5 μg mL^-1). Evidence of PS-NH₂ retention in the gastrointestinal tract in a concentration- and time-dependent manner was also obtained. Mixtures of PS-NH₂ (0.005 and 5 μg mL^-1) with different concentrations of K₂Cr₂O₇ increased the immobilization rate of the larvae after 48 h of exposure, when compared to the K₂Cr₂O₇ alone. Similar results were observed for CuSO₄ in the co-exposure conditions at different concentrations. However, exposing nauplii to a mixture of PS-NH₂ (0.005 μg mL^-1) and CuSO₄ decreased immobilization rate, in comparison to the group exposed to CuSO₄ alone. The present work highlights the potential risk posed by nanoplastics to zooplanktonic species through their interaction with other toxicants.

Contact transfer of engineered nanomaterials in the workplace

This study investigates the potential spread of cadmium selenide quantum dots in laboratory environments through contact of gloves with simulated dry spills on laboratory countertops. Secondary transfer of quantum dots from the contaminated gloves to other substrates was initiated by contact of the gloves with different materials found in the laboratory. Transfer of quantum dots to these substrates was qualitatively evaluated by inspection under ultraviolet illumination. This secondary contact resulted in the delivery of quantum dots to all the evaluated substrates. The amount of quantum dots transferred was quantified by elemental analysis. The residue containing quantum dots picked up by the glove was transferred to at least seven additional sections of the pristine substrate through a series of sequential contacts. These results demonstrate the potential for contact transfer as a pathway for spreading nanomaterials throughout the workplace, and that 7-day-old dried spills are susceptible to the propagation of nanomaterials by contact transfer. As research and commercialization of engineered nanomaterials increase worldwide, it is necessary to establish safe practices to protect workers from the potential for chronic exposure to potentially hazardous materials. Similar experimental procedures to those described herein can be adopted by industries or regulatory agencies to guide the development of their nanomaterial safety programmes.

Molecularly imprinted polymers in toxicology: a literature survey for the last 5 years

The science of toxicology dates back almost to the beginning of human history. Toxic chemicals, which are encountered in different forms, are always among the chemicals that should be investigated in criminal field, environmental application, pharmaceutic, and even industry, where many researches have been carried out studies for years. Almost all of not only drugs but also industrial dyes have toxic side and direct effects. Environmental micropollutants accumulate in the tissues of all living things, especially plants, and show short- or long-term toxic symptoms. Chemicals in forensic science can be known by detecting the effect they cause to the body with the similar mechanism. It is clear that the best tracking tool among analysis methods is molecularly printed polymer-based analytical setups. Different polymeric combinations of molecularly imprinted polymers allow further study on detection or extraction using chromatographic and spectroscopic instruments. In particular, methods used in forensic medicine can detect trace amounts of poison or biological residues on the scene. Molecularly imprinted polymers are still in their infancy and have many variables that need to be developed. In this review, we summarized how molecular imprinted polymers and toxicology intersect and what has been done about molecular imprinted polymers in toxicology by looking at the studies conducted in the last 5 years.

Peptide-Enabled Targeted Delivery Systems for Therapeutic Applications

Receptor-targeting peptides have been extensively pursued for improving binding specificity and effective accumulation of drugs at the site of interest, and have remained challenging for extensive research efforts relating to chemotherapy in cancer treatments. By chemically linking a ligand of interest to drug-loaded nanocarriers, active targeting systems could be constructed. Peptide-functionalized nanostructures have been extensively pursued for biomedical applications, including drug delivery, biological imaging, liquid biopsy, and targeted therapies, and widely recognized as candidates of novel therapeutics due to their high specificity, well biocompatibility, and easy availability. We will endeavor to review a variety of strategies that have been demonstrated for improving receptor-specificity of the drug-loaded nanoscale structures using peptide ligands targeting tumor-related receptors. The effort could illustrate that the synergism of nano-sized structures with receptor-targeting peptides could lead to enrichment of biofunctions of nanostructures.

Transcriptome Profile Alterations with Carbon Nanotubes, Quantum Dots, and Silver Nanoparticles: A Review

Next-generation sequencing (NGS) technology has revolutionized sequence-based research. In recent years, high-throughput sequencing has become the method of choice in studying the toxicity of chemical agents through observing and measuring changes in transcript levels. Engineered nanomaterial (ENM)-toxicity has become a major field of research and has adopted microarray and newer RNA-Seq methods. Recently, nanotechnology has become a promising tool in the diagnosis and treatment of several diseases in humans. However, due to their high stability, they are likely capable of remaining in the body and environment for long periods of time. Their mechanisms of toxicity and long-lasting effects on our health is still poorly understood. This review explores the effects of three ENMs including carbon nanotubes (CNTs), quantum dots (QDs), and Ag nanoparticles (AgNPs) by cross examining publications on transcriptomic changes induced by these nanomaterials.

Consequences of a short-term exposure to a sub lethal concentration of CdO nanoparticles on key life history traits in the fruit fly (Drosophila melanogaster)

Nanoparticles of cadmium oxide (CdO NPs) are among the most common industrial metal oxide nanoparticles. Early adulthood (P1) fruit flies (D. melanogaster) were exposed for 7 days to a sub lethal concentration (0.03 mg CdO NPs/mL, which was 20% of the LC₅₀), spiked into food media to test whether short episodes of CdO NPs exposures early in adult life have long-lasting effects on life history traits such as fecundity well beyond exposure times. All studied life history traits, as well as climbing behavior were adversely affected by exposure to CdO NPs. A blistered wing phenotype was also observed in the non-exposed progeny (F1) of adult flies (P1) and their fecundity was significantly decreased (-50%) compared to the fecundity of non-exposed (control) F1 flies. Expressions of antioxidant enzymes encoding genes; catalase and superoxide dismutase (SOD2) were significantly up regulated in P1 flies compared to control. Expression of metallothionein encoding genes (MTn A-D) were significantly up-regulated in both parent flies (P1) and their progeny (F1) after exposure of P1 flies to CdO NPs compared to non-exposed control flies, suggesting long-term potential effects. Taken together, these findings indicate that short-term exposure to a sub-lethal CdO NP concentration is sufficient to have long-lasting, adverse effects on fruit flies.

Elucidating Carbohydrate-Protein Interactions Using Nanoparticle-Based Approaches

Carbohydrates are present on every living cell and coordinate important processes such as self/non-self discrimination. They are amongst the first molecular determinants to be encountered when cellular interactions are initiated. In particular, they resemble essential molecular fingerprints such as pathogen-, danger-, and self-associated molecular patterns guiding key decision-making in cellular immunology. Therefore, a deeper understanding of how cellular receptors of the immune system recognize incoming particles, based on their carbohydrate signature and how this information is translated into a biological response, will enable us to surgically manipulate them and holds promise for novel therapies. One approach to elucidate these early recognition events of carbohydrate interactions at cellular surfaces is the use of nanoparticles coated with defined carbohydrate structures. These particles are captured by carbohydrate receptors and initiate a cellular cytokine response. In the case of endocytic receptors, the capturing enables the engulfment of exogenous particles. Thereafter, the particles are sorted and degraded during their passage in the endolysosomal pathway. Overall, these processes are dependent on the nature of the endocytic carbohydrate receptors and consequently reflect upon the carbohydrate patterns on the exogenous particle surface. This interplay is still an under-studied subject. In this review, we summarize the application of nanoparticles as a promising tool to monitor complex carbohydrate-protein interactions in a cellular context and their application in areas of biomedicine.

What Is on the Outside Matters-Surface Charge and Dissolve Organic Matter Association Affect the Toxicity and Physiological Mode of Action of Polystyrene Nanoplastics to C. elegans

To better understand nanoplastic effects, the potential for surface functionalization and dissolve organic matter eco-corona formation to modify the mechanisms of action and toxicity of different nanoplastics needs to be established. Here, we assess how different surface charges modifying functionalization (postive (+ve) aminated; neutral unfunctionalized; negative (-ve) carboxylated) altered the toxicity of 50 and 60 nm polystyrene nanoplastics to the nematode Caenorhabditis elegans. The potency for effects on survival, growth, and reproduction reduced in the order +ve aminated > neutral unfunctionalized ≫ -ve carboxylated with toxicity >60-fold higher for the +ve than -ve charged forms. Toxicokinetic-toxicodynamic modeling (DEBtox) showed that the charge-related potency was primarily linked to differences in effect thresholds and dose-associated damage parameters, rather than to toxicokinetic parameters. This suggests that surface functionalization may change the nature of nanoplastic interactions with membrane and organelles leading to variations in toxicity. Eco-corona formation reduced the toxicity of all nanoplastics indicating that organic molecule associations may passivate surfaces. Between particles, eco-corona interactions resulting in more equivalent effects; however, even despite these changes, the order of potency of the charged forms was retained. These results have important implications for the development of future grouping approaches.

The Toxicity of Polystyrene-Based Nanoparticles in Saccharomyces cerevisiae Is Associated with Nanoparticle Charge and Uptake Mechanism

Polystyrene latex (PSL) nanoparticles (NPs), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) liposomes, and hybrid NPs that have different concentrations, sizes, surface charges, and functional groups were used to determine their toxicity to Saccharomyces cerevisiae cells. The size, charge, and morphology of the nanoparticles were characterized by dynamic light scattering, electrophoretic light scattering, scanning transmission electron microscopy, and transmission electron microscopy analysis. The cell viabilities were determined by colony forming unit analysis and confocal laser scanning microscopy imaging. Uptake inhibition studies were performed to determine the internalization mechanism of PSL NPs. At 50 mg/L, both positively and negatively charged NPs were slightly toxic. With increasing concentration, however, full toxicities were observed with positively charged PSL NPs, while a marginal increase in toxicity was obtained with negatively charged PSL NPs. For negatively charged and carboxyl-functionalized NPs, an increase in size induced toxicity, whereas for positively charged and amine-functionalized NPs, smaller-sized NPs were more toxic to yeast cells. Negatively charged NPs were internalized by the yeast cells, but they showed toxicity when they entered the cell vacuole. Positively charged NPs, however, accumulated on the cell surface and caused toxicity. When coated with DOPC liposomes, positively charged NPs became significantly less toxic. We attribute this reduction to the larger-diameter and/or more-agglomerated NPs in the extracellular environment, which resulted in lower interactions with the cell. In addition to endocytosis, it is possible that the negatively charged NPs (30-C-n) were internalized by the cells, partly via direct permeation, which is preferred for high drug delivery efficiency. Negatively charged PSL NP exposure to the yeast cells at low-to-moderate concentrations resulted in low toxicities in the long term. Our results indicate that negatively charged PSL NPs provide safer alternatives as cargo carriers in drug delivery applications. Moreover, the variations in NP size, concentration, and exposure time, along with the use of hybrid systems, have significant roles in nanoparticle-based drug delivery applications in terms of their effects on living organisms.

Cadmium selenide (CdSe) quantum dots cause genotoxicity and oxidative stress in Allium cepa plants

Quantum Dots (QDs), are considered as promising tools for biomedical applications. They have potential applications in agricultural industries, novel pesticide formulations, use in bio-labels and devices to aid genetic manipulation and post-harvest management. Since interactions with higher plants are of important environmental and ecological concern we investigated the cytotoxicity and genotoxicity of CdSe QDs in a model plant (Allium cepa) and established relationships between QDs genotoxic activity and oxidative stress. Allium cepa bulbs with intact roots were exposed to three concentrations of CdSe QDs (12.5, 25 and 50 nM). Cell viability and mitotic frequencies was measured for cytotoxicity, and to assess the genotoxicity DNA lesions, chromosome aberrations and micronuclei were evaluated. We report that QDs exerted significant genotoxic effects, associated with oxidative stress. This could be correlated with the retention of Cd in Allium roots as a dose-dependent increase with the highest uptake at 50 nM of CdSe QD. Oxidative stress induced by CdSe QD treatment activated both, antioxidant (SOD, CAT) scavengers and antioxidant (GPOD, GSH) enzymes. Concentrations as low as 25 nM CdSe QDs were cytotoxic and 50 nM CdSe QDs was found to be genotoxic to the plant. These findings enable to determine the concentrations to be used when practical applications using nanodevices of this type on plants are being considered.

Harmful effects of metal(loid) oxide nanoparticles

Abstract

The incorporation of nanomaterials (NMs), including metal(loid) oxide (MOx) nanoparticles (NPs), in the most diversified consumer products, has grown enormously in recent decades. Consequently, the contact between humans and these materials increased, as well as their presence in the environment. This fact has raised concerns and uncertainties about the possible risks of NMs to human health and the adverse effects on the environment. These concerns underline the need and importance of assessing its nanosecurity. The present review focuses on the main mechanisms underlying the MOx NPs toxicity, illustrated with different biological models: release of toxic ions, cellular uptake of NPs, oxidative stress, shading effect on photosynthetic microorganisms, physical restrain and damage of cell wall. Additionally, the biological models used to evaluate the potential hazardous of nanomaterials are briefly presented, with particular emphasis on the yeast Saccharomyces cerevisiae, as an alternative model in nanotoxicology. An overview containing recent scientific advances on cellular responses (toxic symptoms exhibited by yeasts) resulting from the interaction with MOx NPs (inhibition of cell proliferation, cell wall damage, alteration of function and morphology of organelles, presence of oxidative stress bio-indicators, gene expression changes, genotoxicity and cell dead) is critically presented. The elucidation of the toxic modes of action of MOx NPs in yeast cells can be very useful in providing additional clues about the impact of NPs on the physiology and metabolism of the eukaryotic cell. Current and future trends of MOx NPs toxicity, regarding their possible impacts on the environment and human health, are discussed.

Key points

• The potential hazardous effects of MOx NPs are critically reviewed.

• An overview of the main mechanisms associated with MOx NPs toxicity is presented.

• Scientific advances about yeast cell responses to MOx NPs are updated and discussed.

The membrane-targeting mechanism of host defense peptides inspiring the design of polypeptide-conjugated gold nanoparticles exhibiting effective antibacterial activity against methicillin-resistant Staphylococcus aureus

Multidrug-resistant bacterial infections are a grand challenge to global medical and health systems. Therefore, it is urgent to develop versatile antibacterial strategies that can combat bacterial resistance without displaying toxicity. Here, we synthesize antibacterial polypeptide-conjugated gold nanoparticles that exhibit potent antibacterial activities against clinically isolated multiple drug resistance Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus, and excellent in vitro and in vivo biocompatibility. The antibacterial mechanism study indicates that over-production of reactive oxygen species results in the killing of bacteria. The overall antibacterial performance of these polypeptide-conjugated gold nanoparticles and the convenient synthesis of these polypeptides via lithium hexamethyldisilazide-initiated fast ring-opening polymerization on α-amino acid N-carboxyanhydride imply the potential application of this strategy in treating bacterial infections.

Enhanced Cancer-targeted Drug Delivery Using Precoated Nanoparticles

While protein coronas (PCs) are an important barrier in the clinical application of nanomedicines, the specific effects of PCs on nanoparticles (NPs) in vivo are unclear. Herein, we demonstrated that PCs from clinical sources greatly influenced the active targeting capacities of transferrin-modified NPs (Tf-NPs). Compared to PCs from healthy volunteers, PCs from the plasma of patients with nonsmall cell lung cancer (NSCLC) decreased the A549 uptake of Tf-NPs to a greater degree. The PC proteome revealed that this difference may be mediated by certain proteins in plasma. To attenuate the negative influence of PCs from patients, precoating Tf-NPs with PCs derived from healthy mice significantly enhanced active targeting capacities. Paclitaxel-loaded Tf-NPs with PCs derived from healthy mice showed the strongest antitumor effects in mice with NSCLC. This work illustrates the influence of PCs of ligand-modified NPs in clinical practice and proposes the use of corona-enabled active targeting for precision nanomedicine.

In Vitro and In Vivo Models for Evaluating the Oral Toxicity of Nanomedicines

Toxicity studies for conventional oral drug formulations are standardized and well documented, as required by the guidelines of administrative agencies such as the US Food & Drug Administration (FDA), the European Medicines Agency (EMA) or European Medicines Evaluation Agency (EMEA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). Researchers tend to extrapolate these standardized protocols to evaluate nanoformulations (NFs) because standard nanotoxicity protocols are still lacking in nonclinical studies for testing orally delivered NFs. However, such strategies have generated many inconsistent results because they do not account for the specific physicochemical properties of nanomedicines. Due to their tiny size, accumulated surface charge and tension, sizeable surface-area-to-volume ratio, and high chemical/structural complexity, orally delivered NFs may generate severe topical toxicities to the gastrointestinal tract and metabolic organs, including the liver and kidney. Such toxicities involve immune responses that reflect different mechanisms than those triggered by conventional formulations. Herein, we briefly analyze the potential oral toxicity mechanisms of NFs and describe recently reported in vitro and in vivo models that attempt to address the specific oral toxicity of nanomedicines. We also discuss approaches that may be used to develop nontoxic NFs for oral drug delivery.

Neurotoxic potential of polystyrene nanoplastics in primary cells originating from mouse brain

Polystyrene (PS) and chemically modified compounds in the PS family have long been used in commercial and industrial fields. However, it is poorly understood whether nanoscale-PS microplastic or PS nanoplastic exposure leads to perturbations in fundamental cellular functions, such as proliferation, differentiation, and apoptosis. Herein, we cultured three types of primary cells, including mouse embryonic fibroblasts (MEFs), mixed neuronal cells isolated from embryonic cortex, and cortical astrocytes, and investigated the effects of their exposure to PS nanoplastics with a 100 nm diameter. Although PS nanoplastic exposure did not affect the viability of MEFs or astrocytes, it significantly reduced the viability of mixed neuronal cells. Consistent with the observed effect on cellular viability, levels of the apoptosis marker, cleaved caspase-3, were elevated exclusively in mixed neuronal cells. To investigate whether cells uptake PS nanoplastics into the cytoplasm, we exposed MEFs and neurons to fluorescent PS latex beads and monitored fluorescence over time. We found that PS nanoplastics were deposited and accumulated in the cytoplasm in a concentration-dependent manner. Although astrocytes were not apoptotic upon exposure to PS nanoplastics, they underwent reactive astrocytosis, with increased levels of lipocalin-2 and proinflammatory cytokines. Therefore, our findings suggested that the vulnerability of cells to the deposition and accumulation of PS nanoplastics in the cytoplasm was dependent on cell type. Furthermore, based on our data from primary cells originating from mouse brains, we suggest that reactive astrocytosis may contribute to the neuronal apoptosis seen in defective neurons with PS nanoplastics accumulated in the cell body.

Microalgal ecotoxicity of nanoparticles: An updated review

Nowadays, nanotechnology and its related industries are becoming a rapidly explosive industry that offers many benefits to human life. However, along with the increased production and use of nanoparticles (NPs), their presence in the environment creates a high risk of increasing toxic effects on aquatic organisms. Therefore, a large number of studies focusing on the toxicity of these NPs to the aquatic organisms are carried out which used algal species as a common biological model. In this review, the influences of the physio-chemical properties of NPs and the response mechanisms of the algae on the toxicity of the NPs were discussed focusing on the "assay" studies. Besides, the specific algal toxicities of each type of NPs along with the NP-induced changes in algal cells of these NPs are also assessed. Almost all commonly-used NPs exhibit algal toxicity. Although the algae have similarities in the symptoms under NP exposure, the sensitivity and variability of each algae species to the inherent properties of each NPs are quite different. They depend strongly on the concentration, size, characteristics of NPs, and biochemical nature of algae. Through the assessment, the review identifies several gaps that need to be further studied to make an explicit understanding. The findings in the majority of studies are mostly in laboratory conditions and there are still uncertainties and contradictory/inconsistent results about the behavioral effects of NPs under field conditions. Besides, there remains unsureness about NP-uptake pathways of microalgae. Finally, the toxicity mechanisms of NPs need to be thoughtfully understood which is essential in risk assessment.

Developments in the Application of Nanomaterials for Water Treatment and Their Impact on the Environment

Nanotechnology is an uppermost priority area of research in several nations presently because of its enormous capability and financial impact. One of the most promising environmental utilizations of nanotechnology has been in water treatment and remediation where various nanomaterials can purify water by means of several mechanisms inclusive of the adsorption of dyes, heavy metals, and other pollutants, inactivation and removal of pathogens, and conversion of harmful materials into less harmful compounds. To achieve this, nanomaterials have been generated in several shapes, integrated to form different composites and functionalized with active components. Additionally, the nanomaterials have been added to membranes that can assist to improve the water treatment efficiency. In this paper, we have discussed the advantages of nanomaterials in applications such as adsorbents (removal of dyes, heavy metals, pharmaceuticals, and organic contaminants from water), membrane materials, catalytic utilization, and microbial decontamination. We discuss the different carbon-based nanomaterials (carbon nanotubes, graphene, graphene oxide, fullerenes, etc.), and metal and metal-oxide based nanomaterials (zinc-oxide, titanium dioxide, nano zerovalent iron, etc.) for the water treatment application. It can be noted that the nanomaterials have the ability for improving the environmental remediation system. The examination of different studies confirmed that out of the various nanomaterials, graphene and its derivatives (e.g., reduced graphene oxide, graphene oxide, graphene-based metals, and graphene-based metal oxides) with huge surface area and increased purity, outstanding environmental compatibility and selectivity, display high absorption capability as they trap electrons, avoiding their recombination. Additionally, we discussed the negative impacts of nanomaterials such as membrane damage and cell damage to the living beings in the aqueous environment. Acknowledgment of the possible benefits and inadvertent hazards of nanomaterials to the environment is important for pursuing their future advancement.

Nanoparticles Modified with Cell-Penetrating Peptides: Conjugation Mechanisms, Physicochemical Properties, and Application in Cancer Diagnosis and Therapy

Based on their tunable physicochemical properties and the possibility of producing cell-specific platforms through surface modification with functional biomolecules, nanoparticles (NPs) represent highly promising tools for biomedical applications. To improve their potential under physiological conditions and to enhance their cellular uptake, combinations with cell-penetrating peptides (CPPs) represent a valuable strategy. CPPs are often cationic peptide sequences that are able to translocate across biological membranes and to carry attached cargos inside cells and have thus been recognized as versatile tools for drug delivery. Nevertheless, the conjugation of CPP to NP surfaces is dependent on many properties from both individual components, and further insight into this complex interplay is needed to allow for the fabrication of highly stable but functional vectors. Since CPPs per se are nonselective and enter nearly all cells likewise, additional decoration of NPs with homing devices, such as tumor-homing peptides, enables the design of multifunctional platforms for the targeted delivery of chemotherapeutic drugs. In this review, we have updated the recent advances in the field of CPP-NPs, focusing on synthesis strategies, elucidating the influence of different physicochemical properties, as well as their application in cancer research.

Aquatic toxicity of iron-oxide-doped microplastics to Chlorella pyrenoidosa and Daphnia magna

Novel metal-oxide-doped microplastic particles (MMPs) have become emerging particulate plastics. The toxicity of MMPs in the aquatic environment remains unknown yet. In this study, toxicological effects of a representative MMP (iron-oxide core) with the nominal diameter of 1 μm and two different surface functional groups, amine-modified (MPS (Fe)-NH₂) and carboxyl-modified (MPS (Fe)-COOH) polystyrene, were investigated by toxicity testing using Chlorella pyrenoidosa and Daphnia magna. The aquatic toxicity of two microplastic particles (MPS-NH₂ and MPS-COOH) with the same particle size and surface modification in the absence of iron-oxide core was also observed and compared. Results show that the toxicity of MPS (Fe)-NH₂ to the studied organisms (in terms of median effective concentration) was greater than the MPS (Fe)-COOH and non-iron-oxide-doped microplastic particles. Moreover, the MMPs mainly contributed to the toxicity rather than their dissolved fraction. The accumulation (based on total Fe) of MPS (Fe)-NH₂ in C. pyrenoidosa was higher than the MPS (Fe)-COOH at low effect concentrations. The observations by optical microscopy indicated that the MPS (Fe)-NH₂ was heavily adsorbed on the surface and distributed over the antennae, carapace, and apical spine of D. magna body whereas the MPS (Fe)-COOH was mainly accumulated inside the digestive tract of the daphnia. Furthermore, the analysis of intracellular reactive oxygen species level and antioxidant capacity confirmed that the intensities of the toxic effects cannot be linked to oxidative stress induced by the particles in the algae and daphnids. This work provides valuable insights into the ecological effects of MMPs, which is helpful for the quantitative assessment of food chain transfer of microplastics.

Polymeric and inorganic nanoscopical antimicrobial fillers in dentistry

Failure of dental treatments is mainly due to the biofilm accumulated on the dental materials. Many investigations have been conducted on the advancements of antimicrobial dental materials. Polymeric and inorganic nanoscopical agents are capable of inhibiting microorganism proliferation. Applying them as fillers in dental materials can achieve enhanced microbicidal ability. The present review provides a broad overview on the state-of-the-art research in the field of antimicrobial fillers which have been adopted for incorporation into dental materials over the last 5 years. The antibacterial agents and applications are described, with the aim of providing information for future investigations. STATEMENT OF SIGNIFICANCE: Microbial infection is the primary cause of dental treatment failure. The present review provides an overview on the state-of-art in the field of antimicrobial nanoscopical or polymeric fillers that have been applied in dental materials. Trends in the biotechnological development of these antimicrobial fillers over the last 5 years are reviewed to provide a backdrop for further advancement in this field of research.

Nitrilotriacetic acid-end-functionalized polycaprolactone as a template for polymer–protein nanocarriers

Doxorubicin loaded Nickel-complexed nitrilotriacetic acid-end-functionalized polycaprolactone based biocompatible polymer–protein hybrid nanocarriers were developed in a one-pot process.

Toxicity Evaluation of Quantum Dots (ZnS and CdS) Singly and Combined in Zebrafish (Danio rerio)

The exponential growth of nanotechnology has led to the production of large quantities of nanomaterials for numerous industrial, technological, agricultural, environmental, food and many other applications. However, this huge production has raised growing concerns about the adverse effects that the release of these nanomaterials may have on the environment and on living organisms. Regarding the effects of QDs on aquatic organisms, existing data is scarce and often contradictory. Thus, more information is needed to understand the mechanisms associated with the potential toxicity of these nanomaterials in the aquatic environment. The toxicity of QDs (ZnS and CdS) was evaluated in the freshwater fish Danio rerio. The fishes were exposed for seven days to different concentrations of QDs (10, 100 and 1000 µg/L) individually and combined. Oxidative stress enzymes (catalase, superoxide dismutase and glutathione S-transferase), lipid peroxidation, HSP70 and total ubiquitin were assessed. In general, results suggest low to moderate toxicity as shown by the increase in catalase activity and lipid peroxidation levels. The QDs (ZnS and CdS) appear to cause more adverse effects singly than when tested combined. However, LPO results suggest that exposure to CdS singly caused more oxidative stress in zebrafish than ZnS or when the two QDs were tested combined. Levels of Zn and Cd measured in fish tissues indicate that both elements were bioaccumulated by fish and the concentrations increased in tissues according to the concentrations tested. The increase in HSP70 measured in fish exposed to 100 µg ZnS-QDs/L may be associated with high levels of Zn determined in fish tissues. No significant changes were detected for total ubiquitin. More experiments should be performed to fully understand the effects of QDs exposure to aquatic biota.

Current methods to monitor microalgae-nanoparticle interaction and associated effects

Widespread use of nanoparticles for different applications has diffused their presence in the environment, particularly in water. Many studies have been conducted to evaluate their effects on aquatic organisms. Microalgae are at the base of aquatic trophic chains. These organisms which can be benthic or pelagic, meaning that they can enter into interaction with all kinds of particulate materials whatever their density, and constitute an interesting model study. The purpose of this review was to gather more than sixty studies on microalgae exposure to the different nanoparticles that may be present in the aquatic environment. After a brief description of each type of nanoparticle (metals, silica and plastic) commonly used in ecotoxicological studies, techniques to monitor their properties are presented. Then, different effects on microalgae resulting from interaction with nanoparticles are described as well as the parameters and techniques for monitoring them. The impacts described in the literature are primarily shading, ions release, oxidative stress, adsorption, absorption and disruption of microalgae barriers. Several parameters are proposed to monitor effects such as growth, photosynthesis, membrane integrity, biochemical composition variations and gene expression changes. Finally, in the literature, while different impacts of nanoparticles on microalgae have been described, there is no consensus on evidence of nanomaterial toxicity with regard to microalgae. A parallel comparison of different nanoparticle types appears essential in order to prioritize which factors exert the most influence on toxicity in microalgae cultures: size, nature, surface chemistry, concentration or interaction time.

Are gold nanoparticles and microplastics mixtures more toxic to the marine microalgae Tetraselmis chuii than the substances individually?

The widespread use of microplastics and nanomaterials resulting in environmental contamination is of high concern. Microplastics have been found to modulate the toxicity of other environmental contaminants. Thus, the hypothesis that microplastics increase the toxicity of gold nanoparticles to the marine microalgae Tetraselmis chuii was tested. In a laboratory bioassay, T. chuii cultures were exposed for 96 h to ∼5 nm diameter gold nanoparticles (AuNP) and to virgin 1-5 μm diameter microplastics (MP), alone and in mixture. The treatments were: control; citrate-control; AuNP alone (0.1, 0.3 and 3 mg/L); MP alone (0.3, 0.9 and 4 mg/L) and mixture of the two substances in three different concentrations (0.1 mg/L AuNP + 0.3 mg/L MP; 0.3 mg/L AuNP + 0.9 mg/L MP; 3 mg/l AuNP + 4 mg/L MP). The effect criterion was the inhibition of the average specific growth rate. AuNP alone and MP alone did not cause significant decrease of T. chui average specific growth rate up to 3 mg/L and 4 mg/L, respectively. The mixture containing 3 mg/L AuNP + 4 mg/L MP significantly reduced the average specific growth rate of the microalgae. Therefore, this mixture was more toxic to T. chuii than its components individually. Overall, the results of the present study indicated that the MP and AuNP tested have a relatively low toxicity to T. chuii, but the toxicity increases when they are in mixtures containing high concentrations of both substances. These proof-of-concept findings stress the need of more research on the toxicity of mixtures containing microplastics and nanomaterials.

The Influence of Available Cu and Au Nanoparticles (NPs) on the Survival of Water Fleas (Daphnia pulex)

Applications of nanotechnologies in different sectors and everyday items are very promising and their popularity continues to grow. The number of products containing nanoparticles makes environmental exposure to nanoparticles inevitable. The current understanding of the relationships between nanoparticles and the environment is inadequate despite the fast growth of nanotechnologies. The aim of the study was to investigate the influence of copper and gold nanoparticles on Daphnia pulex survival. Our study included 48-h acute toxicity tests and determination of median lethal concentration values (LC₅₀s) for Cu-NPs and Au-NPs. For nano-copper, 24 h LC₅₀ was assumed > 1 mg/L, and 48 h LC₅₀ = 0.5117 mg/L. For nano-gold the LC₅₀ value after 24 h was 0.4027 mg/L, and after 48 h 0.1007 mg/L. The toxicity of nano -gold solutions was thus found to be higher than that of nano-copper. The addition of Cu-NPs at 0.0625 mg/L and 0.125 mg/L caused an increased multiplication of daphnia, while Au-NPs at 1 mg/L was an inhibitor of reproduction.

Effects of aluminium and cadmium on hatching and swimming ability in developing zebrafish

Aluminium and cadmium are biologically non-essential metals with a role in neurodegenerative and neuromuscular diseases. As an attractive model for neurobehavioural studies, zebrafish at 6 h post fertilization were exposed to 9, 18, 36 and 72 μM CdCl₂ and 50, 100 and 200 μM AlCl₃, respectively, for 72 h, and motility such as distance moved, mean velocity, cumulative movement, meander and heading were measured by DanioVision equipment. The hatching time was also analysed. A delay in the exit from the chorion was observed in all treated larvae with respect to the controls. CdCl₂ acted on the exit from the chorion of larvae with a dose-dependent delay. By contrast, the delay caused by AlCl₃ was greater at low concentrations. A dose-dependent reduction in swimming performance was observed in the larvae exposed to CdCl₂. Instead, for those exposed to AlCl₃, swimming performance improved at higher concentrations although values were in general lower than those of control. All the parameters had a similar trend except the meander parameter which showed a dose-dependent reduction. These data show that cadmium and aluminium can delay hatching and alter swimming ability in the early developmental stages of zebrafish, albeit with different effects, suggesting that exposure to sublethal concentrations of both metals can change behavioural parameters.

Plant virus-based materials for biomedical applications: Trends and prospects

Nanomaterials composed of plant viral components are finding their way into medical technology and health care, as they offer singular properties. Precisely shaped, tailored virus nanoparticles (VNPs) with multivalent protein surfaces are efficiently loaded with functional compounds such as contrast agents and drugs, and serve as carrier templates and targeting vehicles displaying e.g. peptides and synthetic molecules. Multiple modifications enable uses including vaccination, biosensing, tissue engineering, intravital delivery and theranostics. Novel concepts exploit self-organization capacities of viral building blocks into hierarchical 2D and 3D structures, and their conversion into biocompatible, biodegradable units. High yields of VNPs and proteins can be harvested from plants after a few days so that various products have reached or are close to commercialization. The article delineates potentials and limitations of biomedical plant VNP uses, integrating perspectives of chemistry, biomaterials sciences, molecular plant virology and process engineering.

Acutely induced cell mortality in the unicellular green alga Chlamydomonas reinhardtii (Chlorophyceae) following exposure to acrylic resin nanoparticles

Nanoparticles have unique properties that make them attractive for use in industrial and medical technology industries but can also be harmful to living organisms, making an understanding of their molecular mechanisms of action essential. We examined the effect of three different sized poly(isobutyl-cyanoacrylate) nanoparticles (iBCA-NPs) on the unicellular green alga Chlamydomonas reinhardtii. We found that exposure to iBCA-NPs immediately caused C. reinhardtii to display abnormal swimming behaviors. Furthermore, after one hour, most of the cells had stopped swimming and 10%-30% of cells were stained with trypan blue, suggesting that these cells had severely impaired plasma membranes. Observation of the cyto-ultrastructure showed that the cell walls had been severely damaged and that many iBCA-NPs were located in the space between the cell wall and plasma membrane, as well as inside the cytosol in some cases. A comparison of three strains of C. reinhardtii with different cell wall conditions further showed that the cell mortality ratio increased more rapidly in the absence of a cell wall. Interestingly, cell mortality over time was essentially identical regardless of iBCA-NP size if the total surface area was the same. Furthermore, direct observation of the trails of iBCA-NPs indicated that the first trigger was their contact with the cell wall, which is most likely accompanied by the inactivation or removal of adsorbed proteins from the cell wall surface. Cell mortality was accompanied by the overproduction of reactive oxygen species, which was detected more readily in cells grown under constant light rather than in the dark.

Smart nanocarrier-based drug delivery systems for cancer therapy and toxicity studies: A review

Nonspecific distribution and uncontrollable release of drugs in conventional drug delivery systems (CDDSs) have led to the development of smart nanocarrier-based drug delivery systems, which are also known as Smart Drug Delivery Systems (SDDSs). SDDSs can deliver drugs to the target sites with reduced dosage frequency and in a spatially controlled manner to mitigate the side effects experienced in CDDSs. Chemotherapy is widely used to treat cancer, which is the second leading cause of death worldwide. Site-specific drug delivery led to a keen interest in the SDDSs as an alternative to chemotherapy. Smart nanocarriers, nanoparticles used to carry drugs, are at the focus of SDDSs. A smart drug delivery system consists of smart nanocarriers, targeting mechanisms, and stimulus techniques. This review highlights the recent development of SDDSs for a number of smart nanocarriers, including liposomes, micelles, dendrimers, meso-porous silica nanoparticles, gold nanoparticles, super paramagnetic iron-oxide nanoparticles, carbon nanotubes, and quantum dots. The nanocarriers are described in terms of their structures, classification, synthesis and degree of smartness. Even though SDDSs feature a number of advantages over chemotherapy, there are major concerns about the toxicity of smart nanocarriers; therefore, a substantial study on the toxicity and biocompatibility of the nanocarriers has been reported. Finally, the challenges and future research scope in the field of SDDSs are also presented. It is expected that this review will be widely useful for those who have been seeking new research directions in this field and for those who are about to start their studies in smart nanocarrier-based drug delivery.