A Systematic Review of the Genotoxicity and Antigenotoxicity of Biologically Synthesized Metallic Nanomaterials: Are Green Nanoparticles Safe Enough for Clinical Marketing?

Nanoparticle-Mediated Embryotoxicity: Mechanisms of Chemical Toxicity and Implications for Biological Development

Nanoparticles, defined by their nanoscale dimensions and unique physicochemical properties, are widely utilized in healthcare, electronics, environmental sciences, and consumer products. However, increasing evidence of their potential embryotoxic effects during pregnancy underscores the need for a molecular-level understanding of their interactions during embryonic development. Nanoparticles such as titanium dioxide, silver, cerium oxide, copper oxide, and quantum dots can cross the placental barrier and interfere with crucial developmental processes. At the molecular level, they disrupt signaling pathways like Wnt and Hedgehog, induce oxidative stress and inflammation, and cause genotoxic effects, all critical during sensitive phases, such as organogenesis. Furthermore, these nanoparticles interact directly with cellular components, including DNA, proteins, and lipids, impairing cellular function and viability. Innovative strategies to mitigate nanoparticle toxicity, such as surface modifications and incorporation of biocompatible coatings, are discussed as potential solutions to reduce adverse molecular interactions. Various laboratory animal models used to investigate nanoparticle-induced embryotoxicity are evaluated for their efficacy and limitations, providing insights into their applicability for understanding these effects. This Account examines the molecular mechanisms by which nanoparticles compromise embryonic development and emphasizes the importance of designing safer nanoparticles to minimize maternal-fetal exposure risks, particularly in biomedical applications.

Green synthesized metal nanoparticles appear to meet expectations of low ecotoxicity: what about genotoxicity?

Advancements in technology and industry have made the use of nanomaterials indispensable. Due to concerns about the environmental damage caused by classical synthesis methods (Classical Synthesis, CS), the alternative 'Green Synthesis Method' (GS) has been developed, which aims to reduce toxicity by using environmentally friendly materials. This study examines whether nanoparticles synthesized through GS exhibit lower genotoxicity. To this end, research articles published between 2005 and 2025 on nanoparticle synthesis using the GS method were reviewed, and 551 studies were analyzed. The evaluation focused on gold, silver, platinum, copper, iron, and cobalt nanoparticles, which are widely used in various applications. The findings suggest that the GS method offers advantages in terms of genotoxicity. Additionally, this paper provides an in-depth analysis of how the GS method influences the properties of nanoparticles and explores the genotoxic mechanisms of nanoparticles synthesized through this approach.

Harnessing Nanoparticles to Overcome Antimicrobial Resistance: Promises and Challenges

The rise of antimicrobial resistance (AMR) has become a serious global health issue that kills millions of people each year globally. AMR developed in bacteria is difficult to treat and poses a challenge to clinicians. Bacteria develop resistance through a variety of processes, including biofilm growth, targeted area alterations, and therapeutic drug alteration, prolonging the period they remain within cells, where antibiotics are useless at therapeutic levels. This rise in resistance is linked to increased illness and death, highlighting the urgent need for effective solutions to combat this growing challenge. Nanoparticles (NPs) offer unique solutions for fighting AMR bacteria. Being smaller in size with a high surface area, enhancing interaction with bacteria makes the NPs strong antibacterial agents against various infections. In this review, we have discussed the epidemiology and mechanism of AMR development. Furthermore, the role of nanoparticles as antibacterial agents, and their role in drug delivery has been addressed. Additionally, the potential, challenges, toxicity, and future prospects of nanoparticles as antibacterial agents against AMR pathogens have been discussed. The research work discussed in this review links with Sustainable Development Goal 3 (SDG-3), which aims to ensure disease-free lives and promote well-being for all ages.

Mechanisms and Assessment of Genotoxicity of Metallic Engineered Nanomaterials in the Human Environment

Engineered nanomaterials (ENMs) have a broad array of applications in agriculture, engineering, manufacturing, and medicine. Decades of toxicology research have demonstrated that ENMs can cause genotoxic effects on bacteria, mammalian cells, and animals. Some metallic ENMs (MENMs), e.g., metal or metal oxide nanoparticles TiO2 and CuO, induce genotoxicity via direct DNA damage and/or reactive oxygen species-mediated indirect DNA damage. There are various physical features of MENMs that may play an important role in promoting their genotoxicity, for example, size and chemical composition. For a valid genotoxicity assessment of MENMs, general considerations should be given to various factors, including, but not limited to, NM characterization, sample preparation, dosing selection, NM cellular uptake, and metabolic activation. The recommended in vitro genotoxicity assays of MENMs include hprt gene mutation assay, chromosomal aberration assay, and micronucleus assay. However, there are still knowledge gaps in understanding the mechanisms underlying the genotoxicity of MENMs. There are also a variety of challenges in the utilization and interpretation of the genotoxicity assessment assays of MENMs. In this review article, we provide mechanistic insights into the genotoxicity of MENMs in the human environment. We review advances in applying new endpoints, biomarkers, and methods to the genotoxicity assessments of MENMs. The guidance of the United States, the United Kingdom, and the European Union on the genotoxicity assessments of MENMs is also discussed.

An insight into impact of nanomaterials toxicity on human health

In recent years, advances in nanotechnology have significantly influenced electronics manufacturing, industrial processes, and medical research. Various industries have seen a surge in the use of nanomaterials. However, several researchers have raised the alarm about the toxicological nature of nanomaterials, which appear to be quite different from their crude forms. This altered nature can be attributed to their unique physicochemical profile. They can adversely affect human health and the environment. Nanomaterials that have been released into the environment tend to accumulate over time and can cause a significant impact on the ecosystem and organisms with adverse health effects. Increased use of nanoparticles has led to increased human exposure in their daily lives, making them more vulnerable to nanoparticle toxicity. Because of their small size, nanomaterials can readily cross biological membranes and enter cells, tissues, and organs. Therefore, the effect of nanomaterials on the human environment is of particular concern. The toxicological effects of nanomaterials and their mechanisms of action are being researched worldwide. Technological advances also support monitoring new nanomaterials marketed for industrial and household purposes. It is a challenging area because of the exceptional physicochemical properties of nanomaterials. This updated review focuses on the diverse toxicological perspective of nanomaterials. We have discussed the use of different types of nanoparticles and their physiochemical properties responsible for toxicity, routes of exposure, bio-distribution, and mechanism of toxicity. The review also includes various in vivo and in vitro methods of assessing the toxicity of nanomaterials. Finally, this review will provide a detailed insight into nano material-induced toxicological response, which can be beneficial in designing safe and effective nanoparticles.

Antibacterial applications of biologically synthesized Pichia pastoris silver nanoparticles

Objectives

This article highlights the biological synthesis of silver nanoparticles (AgNPs) with their characteristic analysis, and it focuses on the application of synthesized NPs against multidrug resistance (MDR) bacteria. A cytotoxicity study was performed to assess the biocompatibility.

Methods

Silver nanoparticle (AgNPs) formation was confirmed by different characterization methods such as UV-Vis spectrophotometer, Dynamic light scattering (DLS)- Zeta, Fourier transform infrared (FTIR), and Transmission electron microscope (TEM). The antimicrobial activity of the AgNPs was checked against various bacterial strains of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Enterococcus faecalis (E. faecalis), and Klebsiella pneumonia (K. pneumonia) by disc diffusion, minimum inhibition concentration test (MIC), and kinetic studies. The cytotoxicity of NPs against the Vero cell line was studied by cytotoxic assay.

Results

The primary analysis of the formation of nanoparticles (NPs) was made by UV-Vis spectrophotometric analysis at 400 nm. At the same time, the efficient capping checked by FTIR shows the presence of a functional group at different wavelengths 3284, 1641,1573,1388,1288, and 1068 cm-1. At the same time, the transmission electron microscopic analysis (TEM) and DLS show that the shape and size of the synthesized NPs possess an average size of around ∼10-30 nm with spherical morphology. Further, the zeta potential confirmed the stability of the NPs. While the yield of NPs formation from silver salt was determined by an online yield calculator with the EDX analysis results. Synthesized NPs showed bactericidal effects against all the selected MDR pathogens with nontoxic effects against mammalian cells.

Conclusion

Our findings indicate the remarkable antimicrobial activity of the biologically synthesized AgNPs, which can be an antimicrobial agent against multi-drug-resistant bacteria.

The Toxicological Assessment of Anoectochilus burmannicus Ethanolic-Extract-Synthesized Selenium Nanoparticles Using Cell Culture, Bacteria, and Drosophila melanogaster as Suitable Models

Selenium nanoparticles (SeNPs) are worthy of attention and development for nutritional supplementation due to their health benefits in both animals and humans with low toxicity, improved bioavailability, and controlled release, being greater than the Se inorganic and organic forms. Our previous study reported that Anoectochilus burmannicus extract (ABE)-synthesized SeNPs (ABE-SeNPs) exerted antioxidant and anti-inflammatory activities. Furthermore, ABE could stabilize and preserve the biological activities of SeNPs. To promote the ABE-SeNPs as supplementary and functional foods, it was necessary to carry out a safety assessment. Cytotoxicity testing showed that SeNPs and ABE-SeNPs were harmless with no killing effect on Caco2 (intestinal epithelial cells), MRC-5 (lung fibroblasts), HEK293 (kidney cells), LX-2 (hepatic stellate cells), and 3T3-L1 (adipocytes), and were not toxic to isolated human PBMCs and RBCs. Genotoxicity assessments found that SeNPs and ABE-SeNPs did not induce mutations in Salmonella typhimurium TA98 and TA100 (Ames test) as well as in Drosophila melanogaster (somatic mutation and recombination test). Noticeably, ABE-SeNPs inhibited mutation in TA98 and TA100 induced by AF-2, and in Drosophila induced by urethane, ethyl methanesulfonate, and mitomycin c, suggesting their anti-mutagenicity ability. This study provides data that support the safety and anti-genotoxicity properties of ABE-SeNPs for the further development of SeNPs-based food supplements.

Nanomaterials-based biosensor and their applications: A review

A sensor can be called ideal or perfect if it is enriched with certain characteristics viz., superior detections range, high sensitivity, selectivity, resolution, reproducibility, repeatability, and response time with good flow. Recently, biosensors made of nanoparticles (NPs) have gained very high popularity due to their excellent applications in nearly all the fields of science and technology. The use of NPs in the biosensor is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Simultaneously the uses of NPs and electrochemical techniques have led to the emergence of biosensors with high sensitivity and decomposition power. This review summarizes the development of biosensors made of NPssuch as noble metal NPs and metal oxide NPs, nanowires (NWs), nanorods (NRs), carbon nanotubes (CNTs), quantum dots (QDs), and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Acute toxicity study of onion peel-derived gold nano-bioconjugate

The acute anti-inflammatory activity of onion peel-derived gold nano-bioconjugate was already established earlier. The current study was aimed to investigate the acute oral toxicity of onion peel-derived gold nano-bioconjugate (GNBC) for safe therapeutic utilization in vivo. The acute toxicity study was carried out in female mice for 15 days and showed no mortality and any abnormal complications. The lethal dose (LD50) was evaluated and found to be higher than 2000 mg/kg. After 15 days, animals were euthanized and hematological, and biochemical analyses were performed. In all hematological and biochemical assays, treated animals did not show significant toxicity when compared to the control group. The body weight, behavior, and histopathological studies showed that GNBC is nontoxic. Thereby, the results suggest that onion peel-derived gold nano-bioconjugate GNBC can be utilized for therapeutic applications in vivo.

Recent development of metal oxides and chalcogenides as antimicrobial agents

Pathogenic microbes are a major concern in hospitals and other healthcare facilities because they affect the proper performance of medical devices, surgical devices, etc. Due to the antimicrobial resistance or multidrug resistance, combatting these microbial infections has grown to be a significant research area in science and medicine as well as a critical health concern. Antibiotic resistance is where microbes acquire and innately exhibit resistance to antimicrobial agents. Therefore, the development of materials with promising antimicrobial strategy is a necessity. Amongst other available antimicrobial agents, metal oxide and chalcogenide-based materials have shown to be promising antimicrobial agents due to their inherent antimicrobial activity as well as their ability to kill and inhibit the growth of microbes effectively. Moreover, other features including the superior efficacy, low toxicity, tunable structure, and band gap energy has makes metal oxides (i.e. TiO₂, ZnO, SnO₂ and CeO₂ in particular) and chalcogenides (Ag₂S, MoS₂, and CuS) promising candidates for antimicrobial applications as illustrated by examples discussed in this review.

Genotoxicity of Novel Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides in Normal and Cancer Cells In Vitro

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides constitute a novel group of heterocyclic compounds with broad biological activities including anticancer properties. The compounds investigated in this study (MM134, -6, -7, and 9) were found to have antiproliferative activity against BxPC-3 and PC-3 cancer cell lines in micromolar concentrations (IC₅₀ 0.11-0.33 µM). Here, we studied the genotoxic potential of the tested compounds with alkaline and neutral comet assays, accompanied by immunocytochemical detection of phosphorylated γH2AX. We found that pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides induce significant levels of DNA damage in BxPC-3 and PC-3 cells without causing genotoxic effects in normal human lung fibroblasts (WI-38) when used in their respective IC₅₀ concentrations (except for MM134) and showed a dose-dependent increase in DNA damage following 24 h incubation of tested cancer cells with these agents. Furthermore, the influence of MM compounds on DNA damage response (DDR) factors was assessed using molecular docking and molecular dynamics simulation.

Insights into eco-corona formation and its role in the biological effects of nanomaterials from a molecular mechanisms perspective

Broad application of nanotechnology inevitably results in the release of nanomaterials (NMs) into the aquatic environment, and the negative effects of NMs on aquatic organisms have received much attention. Notably, in the natural aquatic environment, ubiquitous ecological macromolecules (i.e., natural organic matter, extracellular polymeric substances, proteins, and metabolites) can easily adsorb onto the surfaces of NMs and form an "eco-corona". As most NMs have such an eco-corona modification, the properties of their eco-corona significantly determine the fate and ecotoxicity of NMs in the natural aquatic ecosystem. Therefore, it is of great importance to understand the role of the eco-corona to evaluate the environmental risks NMs pose. However, studies on the mechanism of eco-corona formation and its resulting nanotoxicity on aquatic organisms, especially at molecular levels, are rare. This review systemically summarizes the mechanisms of eco-corona formation by several typical ecological macromolecules. In addition, the similarities and differences in nanotoxicity between pristine and corona-coated NMs to aquatic organisms at different trophic levels were compared. Finally, recent findings about potential mechanisms on how NM coronas act on aquatic organisms are discussed, including cellular internalization, oxidative stress, and genotoxicity. The literature shows that 1) the formation of an eco-corona on NMs and its biological effect highly depend on both the composition and conformation of macromolecules; 2) both feeding behavior and body size of aquatic organisms at different trophic levels result in different responses to corona-coated NMs; 3) genotoxicity can be used as a promising biological endpoint for evaluating the role of eco-coronas in natural waters. This review provides informative insight for a better understanding of the role of eco-corona plays in the nanotoxicity of NMs to aquatic organisms which will aid the safe use of NMs.

Heavily Gd-Doped Non-Toxic Cerium Oxide Nanoparticles for MRI Labelling of Stem Cells

Recently, human mesenchymal stem cells (hMSc) have attracted a great deal of attention as potential therapeutic agents in the treatment of socially significant diseases. Despite substantial advances in stem-cell therapy, the biological mechanisms of hMSc action after transplantation remain unclear. The use of magnetic resonance imaging (MRI) as a non-invasive method for tracking stem cells in the body is very important for analysing their distribution in tissues and organs, as well as for ensuring control of their lifetime after injection. Herein, detailed experimental data are reported on the biocompatibility towards hMSc of heavily gadolinium-doped cerium oxide nanoparticles (Ce_0.8Gd_0.2O_2-x) synthesised using two synthetic protocols. The relaxivity of the nanoparticles was measured in a magnetic field range from 1 mT to 16.4 T. The relaxivity values (r₁ = 11 ± 1.2 mM^-1 s^-1 and r₁ = 7 ± 1.2 mM^-1 s^-1 in magnetic fields typical of 1.5 and 3 T MRI scanners, respectively) are considerably higher than those of the commercial Omniscan MRI contrast agent. The low toxicity of gadolinium-doped ceria nanoparticles to hMSc enables their use as an effective theranostic tool with improved MRI-contrasting properties.

A review of challenges and prospects of 3D cell-based culture models used for studying drug induced liver injury during early phases of drug development

Drug-induced liver injury (DILI) is the leading cause of compound attrition during drug development. Over the years, a battery of in-vitro cell culture toxicity tests is being conducted to evaluate the toxicity of compounds prior to testing in laboratory animals. Two-dimensional (2D) in-vitro cell culture models are commonly used and have provided a great deal of knowledge; however, these models often fall short in mimicking natural structures of tissues in-vivo. Testing in humans is the most logical method, but unfortunately there are ethical limitations associated with human tests. To overcome these limitations better human-relevant, predictive models are required. The past decade has witnessed significant efforts towards the development of three-dimensional (3D) in-vitro cell culture models better mimicking in-vivo physiology. 3D cell culture has advantages in being representative of the interactions of cells in-vivo and when validated can act as an interphase between 2D cell culture models and in-vivo animal models. The current review seeks to provide an overview of the challenges that make biomarkers used for detection of DILI not to be sensitive enough during drug development and explore how 3D cell culture models can be used to address the gap with the current models.

Binding and Detoxification of Insecticides by Potentially Probiotic Lactic Acid Bacteria Isolated from Honeybee (Apis mellifera L.) Environment-An In Vitro Study

Lactic acid bacteria (LAB) naturally inhabiting the digestive tract of honeybees are known for their ability to detoxify xenobiotics. The effect of chlorpyrifos, coumaphos, and imidacloprid on the growth of LAB strains was tested. All strains showed high resistance to these insecticides. Subsequently, the insecticide binding ability of LAB was investigated. Coumaphos and chlorpyrifos were bound to the greatest extent (up to approx. 64%), and imidacloprid to a much weaker extent (up to approx. 36%). The insecticides were detected in extra- and intracellular extracts of the bacterial cell wall. The ability of selected LAB to reduce the cyto- and genotoxicity of insecticides was tested on two normal (ovarian insect Sf-9 and rat intestinal IEC-6) cell lines and one cancer (human intestinal Caco-2) cell line. All strains exhibited various levels of reduction in the cyto- and genotoxicity of tested insecticides. It seems that coumaphos was detoxified most potently. The detoxification abilities depended on the insecticide, LAB strain, and cell line. The detoxification of insecticides in the organisms of honeybees may reduce the likelihood of the penetration of these toxins into honeybee products consumed by humans and may contribute to the improvement of the condition in apiaries and honeybee health.

Green synthesis of novel stable biogenic gold nanoparticles for breast cancer therapeutics via the induction of extrinsic and intrinsic pathways

Biosynthesis of gold nanoparticles (AuNPs) using algal polysaccharides is a simple, low-cost, and an eco-friendly approach. In the current study, different concentrations of Arthospira platensis exopolysaccharides (EPS) were used to synthetize AuNPs via the reduction of gold ions. The biologically synthesized AuNPs (AuNPs1, AuNPs2, AuNPs3) were prepared in 3 different forms through the utilization of three different ratios of EPS-reducing agents. AuNPs analysis confirmed the spherical shape of the EPS-coated AuNPs. Furthermore, AuNPs prepared by EPS and l-ascorbic acid (AuNPs3) showed more stability than the AuNPs colloidal solution that was prepared using only l-ascorbic acid. Analysis of the antimicrobial effects of AuNPs showed that E. coli was the most sensitive bacterial species for AuNPs3 and AuNPs1 with inhibition percentages of 88.92 and 83.13%, respectively. Also, safety assay results revealed that AuNPs3 was the safest biogenic AuNPs for the tested noncancerous cell line. The anticancer assays of the biogenic AuNPs1, AuNPs2, and AuNPs3 against MCF-7 cell line indicated that this cell line was the most sensitive cell line to all treatments and it showed inhibition percentages of 66.2%, 57.3%, and 70.2% to the three tested AuNPs, respectively. The AuNPs also showed abilities to arrest MCF-7 cells in the S phase (77.34%) and increased the cellular population in the sub G0 phase. Gene expression analysis showed that AuNPs3 down regulated Bcl2, Ikapα, and Survivn genes in MCF-7 treated-cells. Also, transmission electron microscopy (TEM) analysis of MCf-7 cells revealed that AuNPs 3 and AuNPs2 were localized in cell vacuoles, cytoplasm, and perinuclear region.

Biogenic silver/silver chloride nanoparticles inhibit human cancer cells proliferation in vitro and Ehrlich ascites carcinoma cells growth in vivo

Silver/silver chloride nanoparticles (Ag/AgCl-NPs) were synthesized for the first time from the herbal Geodorum densiflorum rhizome extracts and characterized by different techniques. The surface plasmon resonance peak at 455 nm was observed in the UV–Visible spectrum, the average particle size of 25 nm was determined by SEM, XRD reflection peaks (28.00°, 32.42°, 38.28°, 46.38°, 54.94°, 57.60°, 64.64°, and 67.48°) indicated the presence of Ag-NPs and AgCl-NPs, heat stability was confirmed by TGA and FTIR analysis indicated the presence of alcohol/phenol, alkanes, primary amines, nitro compounds, alkyl chloride functional groups. The synthesized Ag/AgCl-NPs, previously synthesized Kaempferia rotunda and Zizyphus mauritiana mediated Ag/AgCl-NPs separately inhibited the proliferation of BxPC-3 cells with the IC₅₀ values of 7.8, 17.1, and 20.1 µg/ml, respectively. In the case of MCF-7 cells, the IC₅₀ values of G. densiflorum- Ag/AgCl-NPs and K. rotunda-Ag/AgCl-NPs were 21.5 and 23.5 µg/ml, respectively. Whereas the IC₅₀ of G. densiflorum-Ag/AgCl-NPs was 28.0 µg/ml against glioblastoma stem cells (GSCs). Induction of apoptosis in GSCs, BxPC-3 and MCF-7 cells was noted followed by NPs treatment. In GSCs, the expression level of NFκB, TNFα, p21, and TLR9 genes were upregulated after treatment with G. densiflorum-Ag/AgCl-NPs while in the MCF-7 cells, the expression of p53, FAS, Caspase-8 and -9, NFκB, MAPK, JNK and p21 genes were increased. G. densiflorum-Ag/AgCl-NPs inhibited 60% and 95% of EAC cells growth at the doses of 2 and 4 mg/Kg/day after intraperitoneal treatment with five consequent days, respectively. A remarkable improvement of hematological parameters with the decreased average tumor weight and increase of 75% life span of G. densiflorum-Ag/AgCl-NPs treated mice were observed. Altogether, this study reported for the first time in vitro anticancer activity of biogenic G. densiflorum-Ag/AgCl-NPs against GSC cells along with MCF-7 and BxPC-3 cells and in vivo anticancer properties against EAC cells.

A review on the toxicity of silver nanoparticles against different biosystems

Despite significant progress made in the past two decades, silver nanoparticles (AgNPs) have not yet made it to the clinical trials. In addition, they showed both positive and negative effects in their toxicity from unicellular organism to well-developed multi-organ system, for example, rat. Although it is generally accepted that capped (bio)molecules have synergistic bioactivities and diminish the toxicity of metallic Ag core, convincing evidence is completely lacking. Therefore, in this review, we first highlight the recent in vivo toxicity studies of chemically manufactured AgNPs, biologically synthesized AgNPs and reference AgNPs of European Commission. Then, their toxic effects are compared with each other and the overlooked factors leading to the potential conflict of obtained toxicity results are discussed. Finally, suggestions are given to better design and conduct the future toxicity studies and to fast-track the successful clinical translation of AgNPs as well.

Integration of Different Graphene Nanostructures with PDMS to Form Wearable Sensors

This paper presents a substantial review of the fabrication and implementation of graphene-PDMS-based composites for wearable sensing applications. Graphene is a pivotal nanomaterial which is increasingly being used to develop multifunctional sensors due to their enhanced electrical, mechanical, and thermal characteristics. It has been able to generate devices with excellent performances in terms of sensitivity and longevity. Among the polymers, polydimethylsiloxane (PDMS) has been one of the most common ones that has been used in biomedical applications. Certain attributes, such as biocompatibility and the hydrophobic nature of PDMS, have led the researchers to conjugate it in graphene sensors as substrates or a polymer matrix. The use of these graphene/PDMS-based sensors for wearable sensing applications has been highlighted here. Different kinds of electrochemical and strain-sensing applications have been carried out to detect the physiological signals and parameters of the human body. These prototypes have been classified based on the physical nature of graphene used to formulate the sensors. Finally, the current challenges and future perspectives of these graphene/PDMS-based wearable sensors are explained in the final part of the paper.

De-novo fabrication of sunlight irradiated silver nanoparticles and their efficacy against E. coli and S. epidermidis

Silver nanoparticles (AgNPs) gained significant attention due to their activity against microbial pathogens, cancer cells, and viral particles etc. Traditional fabrication methods require hazardous chemicals as reducing agents and their usage and disposal pose a significant hazard to environmental ecosystem. Here, a de novo, robust, cost effective and an eco-friendly method is reported to fabricate AgNPs irradiated with sunlight (SL) while using Salvadora persica root extract (SPE) as reducing agent. Sunlight (SL) irradiated S. persica silver nanoparticles (SpNPs) i.e., SL-SpNPs were characterized using multiple techniques and their antibacterial efficacy was evaluated. The SL-SpNPs were synthesized in 10 min. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) analysis revealed their spherical morphology with a size range of 4.5-39.7 nm, while surface plasmon resonance (SPR) peaked at 425 nm. Fourier transform infrared spectroscopy (FTIR) analysis suggested that the reduction of SL-SpNPs was due to the presence of phytochemicals in the SPE. Furthermore, X-ray powder diffraction (P-XRD) pattern depicted the crystal structure of SL-SpNPs, hence proving the presence of AgNPs. Further the antibacterial studies were carried out against Escherichia coli (ATCC 11229) and Staphylococcus epidermidis (ATCC 12228) using Kirby Bauer method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for E. coli were determined to be 1.5 μg/mL and 3.0 μg/mL respectively while MIC and MBC values for S. epidermidis were found to be 12.5 μg/mL and 25 μg/mL respectively. The solar irradiation-based fabrication method and resulting SL-SpNPs can find their utility in many biomedical and environmental applications.

Biosynthesis of silver nanoparticles with antimicrobial and anticancer properties using two novel yeasts

AgNPs are nanomaterials with many potential biomedical applications. In this study, the two novel yeast strains HX-YS and LPP-12Y capable of producing biological silver nanoparticles were isolated. Sequencing of ribosomal DNA-ITS fragments, as well as partial D1/D2 regions of 26S rDNA indicated that the strains are related to species from the genus Metschnikowia. The BioAgNPs produced by HX-YS and LPP-12Y at pH 5.0-6.0 and 26 °C ranged in size from 50 to 500 nm. The antibacterial activities of yeast BioAgNPs against five pathogenic bacteria were determined. The highest antibacterial effect was observed on P. aeruginosa, with additional obvious effects on E. coli ATCC8099 and S. aureus ATCC10231. Additionally, the BioAgNPs showed antiproliferative effects on lung cancer cell lines H1975 and A579, with low toxicity in Beas 2B normal lung cells. Therefore, the AgNPs biosynthesized by HX-YS and LPP-12Y may have potential applications in the treatment of bacterial infections and cancer.

Salivary Leucocytes as In Vitro Model to Evaluate Nanoparticle-Induced DNA Damage

Metal oxide nanoparticles (NPs) have a wide variety of applications in many consumer products and biomedical practices. As a result, human exposure to these nanomaterials is highly frequent, becoming an issue of concern to public health. Recently, human salivary leucocytes have been proposed as an adequate non-invasive alternative to peripheral blood leucocytes to evaluate genotoxicity in vitro. The present study focused on proving the suitability of salivary leucocytes as a biomatrix in the comet assay for in vitro nanogenotoxicity studies, by testing some of the metal oxide NPs most frequently present in consumer products, namely, titanium dioxide (TiO2), zinc oxide (ZnO), and cerium dioxide (CeO2) NPs. Primary and oxidative DNA damage were evaluated by alkaline and hOGG1-modified comet assay, respectively. Any possible interference of the NPs with the methodological procedure or the hOGG1 activity was addressed before performing genotoxicity evaluation. Results obtained showed an increase of both primary and oxidative damage after NPs treatments. These data support the use of salivary leucocytes as a proper and sensitive biological sample for in vitro nanogenotoxicity studies, and contribute to increase the knowledge on the impact of metal oxide NPs on human health, reinforcing the need for a specific regulation of the nanomaterials use.

Green-synthesized CeO2 nanoparticles for photocatalytic, antimicrobial, antioxidant and cytotoxicity activities

Cerium oxide nanoparticles (CeO2 NPs) are a sought-after material in numerous fields due to their potential applications such as in catalysis, cancer therapy, photocatalytic degradation of pollutants, sensors, polishing agents. Green synthesis usually involves the production of CeO2 assisted by organic extracts obtained from plants, leaves, flowers, bacteria, algae, food, fruits, etc. The phytochemicals present in the organic extracts adhere to the NPs and act as reducing and/or oxidizing agents and capping agents to stabilize the NPs, modify the particle size, morphology and band gap energy of the as-synthesized materials, which would be advantageous for numerous applications. This review focuses on the green extract-mediated synthesis of CeO2 NPs and discusses the effects on CeO2 NPs of various synthesis methods that have been reported. Several photocatalytic, antimicrobial, antioxidant and cytotoxicity applications have been evaluated, compared and discussed. Future prospects are also suggested.

Biological Nanofactories: Using Living Forms for Metal Nanoparticle Synthesis

Metal nanoparticles are nanosized entities with dimensions of 1-100 nm that are increasingly in demand due to applications in diverse fields like electronics, sensing, environmental remediation, oil recovery and drug delivery. Metal nanoparticles possess large surface energy and properties different from bulk materials due to their small size, large surface area with free dangling bonds and higher reactivity. High cost and pernicious effects associated with the chemical and physical methods of nanoparticle synthesis are gradually paving the way for biological methods due to their eco-friendly nature. Considering the vast potentiality of microbes and plants as sources, biological synthesis can serve as a green technique for the synthesis of nanoparticles as an alternative to conventional methods. A number of reviews are available on green synthesis of nanoparticles but few have focused on covering the entire biological agents in this process. Therefore present paper describes the use of various living organisms like bacteria, fungi, algae, bryophytes and tracheophytes in the biological synthesis of metal nanoparticles, the mechanisms involved and the advantages associated therein.

In Vitro Three-Dimensional Liver Models for Nanomaterial DNA Damage Assessment

Whilst the liver possesses the ability to repair and restore sections of damaged tissue following acute injury, prolonged exposure to engineered nanomaterials (ENM) may induce repetitive injury leading to chronic liver disease. Screening ENM cytotoxicity using 3D liver models has recently been performed, but a significant challenge has been the application of such in vitro models for evaluating ENM associated genotoxicity; a vital component of regulatory human health risk assessment. This review considers the benefits, limitations, and adaptations of specific in vitro approaches to assess DNA damage in the liver, whilst identifying critical advancements required to support a multitude of biochemical endpoints, focusing on nano(geno)toxicology (e.g., secondary genotoxicity, DNA damage, and repair following prolonged or repeated exposures).

Silver Nanoparticles Synthesized Using Carica papaya Leaf Extract (AgNPs-PLE) Causes Cell Cycle Arrest and Apoptosis in Human Prostate (DU145) Cancer Cells

Treatment of cancer has been limited by the poor efficacy and toxicity profiles of available drugs. There is a growing demand to develop alternative approaches to combat cancer such as use of nano-formulation-based drugs. Here, we report biosynthesis and characterization of silver nanoparticles (AgNPs) with papaya leaf extract (PLE) and its anti-cancer properties against different human cancer cells. Purified nanoparticles were characterized by standard techniques, such as TEM, STM, SEM, EDS, XRD, and FTIR. Furthermore, cytotoxic activity of AgNPs-PLE was carried out against different human cancer cells and non-tumorigenic human keratinocytes cells. AgNPs-PLE when compared with AgNPs-citric acid or PLE showed better efficacy against cancer cells and was also relatively less toxic to normal cells. Treatment of DU145 cells with AgNPs-PLE (0.5-5.0 μg/ml) for 24-48 h lowered total cell number by 24-36% (P < 0.05). Inhibition of cell growth was linked with arrest of cell cycle at G2/M phase at 24 h, while G1 and G2/M phase arrests at 48 h. ROS production was observed at earlier time points in presence of AgNPs-PLE, suggesting its role behind apoptosis in DU145 cells. Induction of apoptosis (57%) was revealed by AO/EB staining in DU145 cells along with induction of Bax, cleaved caspase-3, and cleaved PARP proteins. G1-S phase cell cycle check point marker, cyclin D1 was down-regulated along with an increase in cip1/p21 and kip1/p27 tumor suppressor proteins by AgNPs-PLE. These findings suggest the anti-cancer properties of AgNPs-PLE.

Salvadora persica mediated synthesis of silver nanoparticles and their antimicrobial efficacy

Silver nanoparticles (AgNPs) exhibit strong antimicrobial properties against many pathogens. Traditionally employed chemical methods for AgNPs synthesis are toxic for the environment. Here, we report a quicker, simpler, and environmentally benign process to synthesize AgNPs by using an aqueous 'root extract' of Salvadora persica (Sp) plant as a reducing agent. The synthesized Salvadora persica nano particles (SpNPs) showed significantly higher antimicrobial efficacy compared to earlier reported studies. We characterized SpNPs using UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), Dynamic Light Scattering (DLS) and X-ray powder diffraction (P-XRD). UV-Vis spectrum showed the highest absorbance at 420 nm. FTIR analysis depicts presence of bond stretching including OH- (3300 cm-1), C=N- (2100 cm-1) and NH- (1630 cm-1) which are attributed in the involvement of phenolics, proteins or nitrogenous compounds in reduction and stabilization of AgNPs. TEM, FE-SEM and DLS analysis revealed the spherical and rod nature of SpNPs and an average size of particles as 37.5 nm. XRD analysis showed the presence of the cubic structure of Ag which confirmed the synthesis of silver nanoparticles. To demonstrate antimicrobial efficacy, we evaluated SpNPs antimicrobial activity against two bacterial pathogens (Escherichia coli (ATCC 11229) and Staphylococcus epidermidis (ATCC 12228)). SpNPs showed a significantly high inhibition for both pathogens and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were found to be 0.39 µg/mL and 0.78 µg/mL for E. coli while 0.19 µg/mL and 0.39 µg/mL for S. epidermidis respectively. Further, Syto 16 staining of bacterial cells provided a supplemental confirmation of the antimicrobial efficacy as the bacterial cells treated with SpNPs stop to fluoresce compared to the untreated bacterial cells. Our highly potent SpNPs will likely have a great potential for many antimicrobial applications including wound healing, water purification, air filtering and other biomedical applications.

Biological synthesis of silver nanoparticles using animal blood, their preventive efficiency of bacterial species, and ecotoxicity in common carp fish

Possible high biodeterioration of the microorganisms due to their metabolic pathway and activities on stone materials causes solemn problems in cultural heritage. Different kinds of laboratory-scale methods have been used for the reduction of microbial growth, that is, chemical, mechanical, and physical, which are cost-effective and not ecofriendly. In the current study, an ecofriendly approach utilizing silver nanoparticles were synthesized using sheep blood serum. Transmission electron microscopy results have confirmed the spherical and well dispersed silver nanoparticles with an average size of 32.49 nm, while energy dispersive X-ray has shown the abundance of silver nanoparticles. The efficiency against bacterial species was verified through laboratory-scale testing. The strong antibacterial activity was confirmed when B-AgNPs was tested against different bacterial species isolated from the Beishiku Cave Temple. The largest zone of inhibition was measured 26.48 ± 0.14 mm against Sphingomonas sp. while the smallest zone of inhibition measured was 9.70 ± 0.27 mm against Massilia sp. Moreover, these ecofriendly B-AgNPs were tested for daily based dose in different concentrations (0.03, 0.06, and 0.09 mg/L) against common carp fish for a long exposure (20 days) and 6.5% fatality was found. The highest lethal concentration (LC₅₀ ) for fish (0.61 ± 0.09 mg/L). No doubt, the laboratory scale applications have revealed the best results with minute toxicity in fish. Therefore, sheep serum should be continued to synthesize silver nanoparticles on a large scale. A strict monitoring system should be developed for the synthesis and application of AgNPs.

Nanoencapsulation of Promising Bioactive Compounds to Improve Their Absorption, Stability, Functionality and the Appearance of the Final Food Products

The design of functional foods has grown recently as an answer to rising consumers' concerns and demands for natural, nutritional and healthy food products. Nanoencapsulation is a technique based on enclosing a bioactive compound (BAC) in liquid, solid or gaseous states within a matrix or inert material for preserving the coated substance (food or flavor molecules/ingredients). Nanoencapsulation can improve stability of BACs, improving the regulation of their release at physiologically active sites. Regarding materials for food and nutraceutical applications, the most used are carbohydrate-, protein- or lipid-based alternatives such as chitosan, peptide-chitosan and β-lactoglobulin nanoparticles (NPs) or emulsion biopolymer complexes. On the other hand, the main BACs used in foods for health promoting, including antioxidants, antimicrobials, vitamins, probiotics and prebiotics and others (minerals, enzymes and flavoring compounds). Nanotechnology can also play notable role in the development of programmable food, an original futuristic concept promising the consumers to obtain high quality food of desired nutritive and sensory characteristics.

Rapid green synthesis of non-cytotoxic silver nanoparticles using aqueous extracts of 'Golden Delicious' apple pulp and cumin seeds with antibacterial and antioxidant activity

Abstract

A simple, facile and rapid microwave irradiated system was applied to synthesize silver nanoparticles using 'Golden Delicious' apple pulp (Malus domestica) and cumin (Cuminum cyminum) seed extracts. The phytosynthesized AgNPs were characterized by Ultraviolet–Visible Spectroscopy (UV–vis), Fourier transform infrared (FTIR), X-ray Diffraction (XRD) Transmission Electron Microscopy (TEM) and Zeta sizer analysis. In the study, the presence of face-centered cubic crystalline structured metallic silver in AgNPs from apple and cumin extracts and the monodisperse nature of AgNPs with the size distribution range of 5.46–20 nm and 1.84–20.57 nm were confirmed, respectively. This study established an efficient green synthesis approach that created so far, the smallest silver nanoparticles by using these two extracts. According to the results obtained, AgNPs synthesized using both extracts were non-toxic against L929 mouse fibroblast cells, while they were effective against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria with a greater effect on S. aureus. Moreover, AgNPs synthesized through cumin extract exhibited a higher ABTS scavenging ability (96.43 ± 0.78% at 160 μg/mL) in comparison to apple pulp extract mediated AgNPs, while both AgNPs showed lower activity for DPPH (27.84 ± 0.56% and 13.12 ± 0.32% from cumin seed and apple pulp extracts, respectively). In summary, our results suggest the green non-cytotoxic AgNPs synthesized in this study could be a promising template for further biological and clinical applications.

Graphical abstract

Biological effects, including oxidative stress and genotoxic damage, of polystyrene nanoparticles in different human hematopoietic cell lines

In recent years the terms "micro-/nanoplastics" (MNPLs) have caught special attention due to the increasing levels by which humans are exposed. Among MNPLs, polystyrene nanoparticles (PSNPs) are one of the most represented MNPLs in the environment. These tiny particles may enter into the human body, translocate through human barriers, interacting with blood and lymphatic immune cells, and reaching secondary organs. By using three different human leukocytic cell lines: Raji-B (B-lymphocytes), TK6 (lymphoblasts) and THP-1 (monocytes), we pursued to determine the effects of these PSNPs on the immune cell population. With this aim, the three cell lines were exposed to spherical PSNPs of about 50 nm of diameter and cytotoxicity, cellular uptake, reactive oxygen species (ROS) production, and genotoxicity were assessed at different time-points. Results show differences in all the measured endpoints, among the selected cell lines. Thus, whilst the monocytic THP-1 cells showed the highest particle internalization, no adverse effects were observed in such cells. On the other side, although Raji-B and TK6 showed lesser PSNPs uptake, mild toxicity, ROS production and genotoxicity were detected. These results highlight the importance of the cell line selection when the biological effects of PSNPs are evaluated.

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.

Green One-Step Synthesis of Medical Nanoagents for Advanced Radiation Therapy

PURPOSE

Metal-based nanoparticles (M-NPs) have attracted great attention in nanomedicine due to their capacity to amplify and improve the tumor targeting of medical beams. However, their simple, efficient, high-yield and reproducible production remains a challenge. Currently, M-NPs are mainly synthesized by chemical methods or radiolysis using toxic reactants. The waste of time, loss of material and potential environmental hazards are major limitations.

MATERIALS AND METHODS

This work proposes a simple, fast and green strategy to synthesize small, non-toxic and stable NPs in water with a 100% production rate. Ionizing radiation is used to simultaneously synthesize and sterilize the containing NPs solutions. The synthesis of platinum nanoparticles (Pt NPs) coated with biocompatible poly(ethylene glycol) ligands (PEG) is presented as proof of concept. The physicochemical properties of NPs were studied by complementary specialized techniques. Their toxicity and radio-enhancing properties were evaluated in a cancerous in vitro model. Using plasmid nanoprobes, we investigated the elementary mechanisms underpinning radio-enhancement.

RESULTS AND DISCUSSION

Pt NPs showed nearly spherical-like shapes and an average hydrodynamic diameter of 9 nm. NPs are zero-valent platinum successfully coated with PEG. They were found non-toxic and have the singular property of amplifying cell killing induced by γ-rays (14%) and even more, the effects of carbon ions (44%) used in particle therapy. They induce nanosized-molecular damage, which is a major finding to potentially implement this protocol in treatment planning simulations.

CONCLUSION

This new eco-friendly, fast and simple proposed method opens a new era of engineering water-soluble biocompatible NPs and boosts the development of NP-aided radiation therapies.

Genoprotective activities of plant natural substances in cancer and chemopreventive strategies in the context of 3P medicine

Severe durable changes may occur to the DNA structure caused by exogenous and endogenous risk factors initiating the process of carcinogenesis. By evidence, a large portion of malignancies have been demonstrated as being preventable. Moreover, the targeted prevention of cancer onset is possible, due to unique properties of plant bioactive compounds. Although genoprotective effects of phytochemicals have been well documented, there is an evident lack of articles which would systematically present the spectrum of anticancer effects by phytochemicals, plant extracts, and plant-derived diet applicable to stratified patient groups at the level of targeted primary (cancer development) and secondary (cancer progression and metastatic disease) prevention. Consequently, clinical implementation of knowledge accumulated in the area is still highly restricted. To stimulate coherent co-development of the dedicated plant bioactive compound investigation on one hand and comprehensive cancer preventive strategies on the other hand, the current paper highlights and deeply analyses relevant evidence available in the area. Key molecular mechanisms are presented to detail genoprotective and anticancer activities of plants and phytochemicals. Clinical implementation is discussed. Based on the presented evidence, advanced chemopreventive strategies in the context of 3P medicine are considered.