The distinct physicochemical and biological characteristics of metal and metal oxide nanoparticles have attracted considerable interest in various branches of dentistry as potential solutions to the problems associated with conventional dental treatments and to promote human health. Many scientists have been interested in nanoparticles for endodontic applications in the last several decades. Endodontic treatment is more likely to be successful when metal and metal oxide nanoparticles are used. Endodontic therapies often make use of nanoparticles made of metals and metal oxides. The effect of nano metals and metal oxide in endodontic treatments has not been published or is not widely available in the literature. Therefore, this paper aims to review recent studies on the development and application of some important metal and metal oxide nanoparticles such as silver and silver oxide, zinc oxide, zirconium oxide, magnesium oxide, titanium dioxide and other metal oxide nanoparticles in endodontic therapeutic procedures.

Antimicrobial resistance (AMR) is growing into a major public health crisis worldwide. The reducing alternatives to conventional agents starve for novel antimicrobial agents. Due to their unique magnetic properties and excellent biocompatibility, iron oxide nanoparticles (IONPs) are the most preferable nanomaterials in biomedicine, including antibacterial therapy, primarily through reactive oxygen species (ROS) production. IONP characteristics, including their size, shape, surface charge, and superparamagnetism, influence their biodistribution and antibacterial activity. External magnetic fields, foreign metal doping, and surface, size, and shape modification improve the antibacterial effect of IONPs. Despite a few disadvantages, IONPs are expected to be promising antibacterial agents of a new generation.

Biofilm formation by bacteria poses a significant challenge across diverse industries, displaying resilience against conventional antimicrobial agents. Nanoparticles emerge as a promising alternative for addressing biofilm-related issues. This review aims to assess the efficacy of metal and metal oxide nanoparticles in inhibiting or disrupting biofilm formation by various bacterial species. It delineates trends, identifies gaps, and outlines avenues for future research, emphasizing best practices and optimal nanoparticles for biofilm prevention and eradication. Additionally, it underscores the potential of nanoparticles as substitutes for traditional antibiotics in healthcare and combating antibiotic resistance. A systematic literature search, encompassing Web of Science, PubMed, and Google Scholar from 2015 to 2023, yielded 48 publications meeting the review criteria. These studies employed diverse methods to explore the antibacterial activity of nanoparticles against biofilmforming bacteria strains. The implications of this study are profound, offering prospects for novel antimicrobial agents targeting biofilm-forming bacteria, often resistant to conventional antibiotics. In conclusion, nanoparticles present a promising frontier in countering biofilm-forming bacteria. This review delivers a structured analysis of current research, providing insights into the potential and challenges of nanoparticle utilization against biofilm-related challenges. While nanoparticles exhibit inherent antimicrobial properties with applications spanning healthcare, agriculture, and industries, the review acknowledges limitations such as the narrow scope of tested nanoparticles and the imperative need for extensive research on long-term toxicity and environmental impacts.

The increasing release of engineered nanoparticles (ENPs) in aquatic ecosystems stresses the need for stringent investigations of nanoparticle mixture toxicity towards aquatic organisms. Here, the individual and combined immunotoxicity of two of the most consumed ENPs, the ZnO and the TiO2 ones, was investigated on rainbow trout juveniles (Oncorhynchus mykiss). Fish were exposed to environmentally realistic concentrations (21 and 210 µg L-1 for the ZnO and 210 µg L-1 for the TiO2) for 28 days, and then challenged with the pathogenic bacterium, Aeromonas salmonicida achromogenes. Antioxidant and innate immune markers were assessed before and after the bacterial infection. None of the experimental conditions affected the basal activity of the studied innate immune markers and the redox balance. However, following the bacterial infection, the expression of genes coding for pro and anti-inflammatory cytokines (il1β and il10), as well as innate immune compounds (mpo) were significantly reduced in fish exposed to the mixture. Conversely, exposure to ZnO NPs alone seemed to stimulate the immune response by enhancing the expression of the IgM and c3 genes for instance. Overall, our results suggest that even though the tested ENPs at their environmental concentration do not strongly affect basal immune functions, their mixture may alter the development of the immune response when the organism is exposed to a pathogen by interfering with the inflammatory response.

Synthetic dyes play a crucial role in our daily lives, especially in clothing, leather accessories, and furniture manufacturing. Unfortunately, these potentially carcinogenic substances are significantly impacting our water systems due to their widespread use. Dyes from various sources pose a serious environmental threat owing to their persistence and toxicity. Regulations underscore the urgency in addressing this problem. In response to this challenge, metal oxide nanoparticles such as titanium dioxide (TiO2), zinc oxide (ZnO), and iron oxide (Fe3O4) have emerged as intriguing options for dye degradation due to their unique characteristics and production methods. This paper aims to explore the types of nanoparticles suitable for dye degradation, various synthesis methods, and the properties of nanoparticles. The study elaborates on the photocatalytic and adsorption-desorption activities of metal oxide nanoparticles, elucidating their role in dye degradation and their application potential. Factors influencing degradation, including nanoparticle properties and environmental conditions, are discussed. Furthermore, the paper provides relevant case studies, practical applications in water treatment, and effluent treatment specifically in the textile sector. Challenges such as agglomeration, toxicity concerns, and cost-effectiveness are acknowledged. Future advancements in nanomaterial synthesis, their integration with other materials, and their impact on environmental regulations are potential areas for development. In conclusion, metal oxide nanoparticles possess immense potential in reducing dye pollution, and further research and development are essential to define their role in long-term environmental management.

Numerous processes such as solubility, agglomeration/aggregation, or protein corona formation may change over time and significantly affect engineered nanomaterial (ENM) structure, property, and availability, resulting in their reduced or increased toxicological activity. Therefore, understanding the dynamics of these processes is essential for assessing and managing the risks of ENMs during their lifecycle, ensuring safety by design. Of these processes, the importance of solubility (i.e., the ability to release ions from the surface) is undeniable. Thus, we propose a practical approach, the Kalapus equation (KEq), to determine ENMs\' dissolution over time. As a proof-of-concept, the KEq was applied to determine the solubility of six commercially used metal and metal oxide nanoparticles over time. The KEq exhibited a higher coefficient of determination (R2 = 0.995-0.999) than the logarithmic equation (R2 = 0.835-0.986), and the pseudo-first-order equation (R2 = 0.915-0.994) over a range of experimental data. The newly introduced Kalapus equation outperformed the logarithmic and pseudo-first-order equations when extrapolating beyond the time range in which solubility was experimentally determined. The mean absolute error in solubility prediction for the KEq was 3.29 % and 4.28 % for the first and second data points, respectively, significantly lower than the 13.46 % and 18.05 % observed for the pseudo-first-order/first-order equation. The proposed equation can be used as a part of New Generation Risk Assessment (NGRA) methodology, especially new Integrated Approaches to Testing and Assessments (IATAs).

Metal oxide nanoparticles (MONP/s) induce DNA damage, which is influenced by their physicochemical properties. In this study, the high-throughput CometChip and micronucleus (MicroFlow) assays were used to investigate DNA and chromosomal damage in mouse lung epithelial cells induced by nano and bulk sizes of zinc oxide, copper oxide, manganese oxide, nickel oxide, aluminum oxide, cerium oxide, titanium dioxide, and iron oxide. Ionic forms of MONPs were also included. The study evaluated the impact of solubility, surface coating, and particle size on response. Correlation analysis showed that solubility in the cell culture medium was positively associated with response in both assays, with the nano form showing the same or higher response than larger particles. A subtle reduction in DNA damage response was observed post-exposure to some surface-coated MONPs. The observed difference in genotoxicity highlighted the mechanistic differences in the MONP-induced response, possibly influenced by both particle stability and chemical composition. The results highlight that combinations of properties influence response to MONPs and that solubility alone, while playing an important role, is not enough to explain the observed toxicity. The results have implications on the potential application of read-across strategies in support of human health risk assessment of MONPs.

Microplastics (MPs) are pervasive and undergo environmental aging processes, which alters potential interaction with the co-contaminants. Hence, to assess their contaminant-carrying capacity, mimicking the weathering characteristics of secondary MPs is crucial. To this end, the present study investigated the interaction of Zinc oxide (nZnO) nanoparticles with non-irradiated (NI) and UV-irradiated (UI) forms of the most abundant MPs, such as polypropylene (PP) and polystyrene (PS), in aqueous environments. SEM images revealed mechanical abrasions on the surfaces of NI-MPs and their subsequent photoaging caused the formation of close-ended and open-ended cracks in UI-PP and UI-PS, respectively. Batch-sorption experiments elucidated nZnO uptake kinetics by PP and PS MPs, suggesting a sorption-desorption pathway due to weaker and stronger sorption sites until equilibrium was achieved. UI-PP showed higher nZnO (∼3000 mg/kg) uptake compared to NI-PP, while UI-PS showed similar or slightly decreased nZnO (∼2000 mg/kg) uptake compared to NI-PS. FTIR spectra and zeta potential measurements revealed electrostatic interaction as the dominant interaction mechanism. Higher nZnO uptake by MPs was noted between pH 6.5 and 8.5, whereas it decreased beyond this range. Despite DOM, MPs always retained ∼874 mg/kg nZnO irrespective of MPs type and extent of aging. The experimental results in river water showed higher nZnO uptake on MPs compared to DI water, attributed to mutual effect of ionic competition, DOM, and MP hydrophobicity. In the case of humic acids, complex synthetic and natural water matrices, NI-MPs retained more nZnO than UI-MPs, suggesting that photoaged MPs sorb less nZnO under environmental conditions than non-photoaged MPs. These findings enhance our understanding on interaction of the MPs with co-contaminants in natural environments.

Tuberculosis (TB) continues to pose a significant global health threat, with millions of new infections recorded annually. Current treatment strategies, such as Directly Observed Treatment (DOT), face challenges, including patient non-compliance and the emergence of drug-resistant TB strains. In response to these obstacles, innovative approaches utilizing inorganic/metallic nanomaterials have been developed to enhance drug delivery to target alveolar macrophages, where Mycobacterium tuberculosis resides. These nanomaterials have shown effectiveness against various strains of TB, offering benefits such as improved drug efficacy, minimized side effects, and sustained drug release at the infection site. This comprehensive review explores the applications of different metal nanoparticles, metal oxide nanoparticles, and metal-metal oxide hybrid nanoparticles in the management of TB, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. The synergistic effects of combining inorganic nanoparticles with conventional anti-TB drugs have demonstrated promising results in combating TB infections. Further research and development in this field hold great promise for overcoming the challenges faced in current TB therapy and improving patient outcomes.

Currently, the alteration of external factors during crude oil extraction easily disrupts the thermodynamic equilibrium of asphaltene, resulting in the continuous flocculation and deposition of asphaltene molecules in crude oil. This accumulation within the pores of reservoir rocks obstructs the pore throat, hindering the efficient extraction of oil and gas, and consequently, affecting the recovery of oil and gas resources. Therefore, it is crucial to investigate the principles of asphaltene deposition inhibition and the synthesis of asphaltene inhibitors. In recent years, the development of nanotechnology has garnered significant attention due to its unique surface and volume effects. Nanoparticles possess a large specific surface area, high adsorption capacity, and excellent suspension and catalytic abilities, exhibiting unparalleled advantages compared with traditional organic asphaltene inhibitors, such as sodium dodecyl benzene sulfonate and salicylic acid. At present, there are three primary types of nanoparticle inhibitors: metal oxide nanoparticles, organic nanoparticles, and inorganic nonmetal nanoparticles. This paper reviews the recent advancements and application challenges of nanoparticle asphaltene deposition inhibition technology based on the mechanism of asphaltene deposition and nano-inhibitors. The aim was to provide insights for ongoing research in this field and to identify potential future research directions.