Antibiotics are playing an increasingly important role in clinical antibacterial applications. However, their abuse has also brought toxic and side effects, drug-resistant pathogens, decreased immunity and other problems. New antibacterial schemes in clinic are urgently needed. In recent years, nano-metals and their oxides have attracted wide attention due to their broad-spectrum antibacterial activity. Nano-silver, nano-copper, nano-zinc and their oxides are gradually applied in biomedical field. In this study, the classification and basic properties of nano-metallic materials such as conductivity, superplasticity, catalysis, and antibacterial activities were firstly introduced. Secondly, the common preparation techniques, including physical, chemical and biological methods, were summarized. Subsequently, four main antibacterial mechanisms, such as cell membrane, oxidative stress, DNA destruction and cell respiration reduction, were summarized. Finally, the effect of size, shape, concentration and surface chemical characteristics of nano-metals and their oxides on antibacterial effectiveness and the research status of biological safety such as cytotoxicity, genotoxicity and reproductive toxicity were reviewed. At present, although nano-metals and their oxides have been applied in medical antibacterial, cancer treatment and other clinical fields, some issues such as the development of green preparation technology, the understanding of antibacterial mechanism, the improvement of biosafety, and the expansion of application fields, require further exploration.
Oxides/chemistry* ; Metal Nanoparticles/chemistry* ; Anti-Bacterial Agents/chemistry* ; Zinc ; Copper

The wide use of ZnO and CuO nanoparticles in research, medicine, industry, and other fields has raised concerns about their biosafety. It is therefore unavoidable to be discharged into the sewage treatment system. Due to the unique physical and chemical properties of ZnO NPs and CuO NPs, it may be toxic to the members of the microbial community and their growth and metabolism, which in turn affects the stable operation of sewage nitrogen removal. This study summarizes the toxicity mechanism of two typical metal oxide nanoparticles (ZnO NPs and CuO NPs) to nitrogen removal microorganisms in sewage treatment systems. Furthermore, the factors affecting the cytotoxicity of metal oxide nanoparticles (MONPs) are summarized. This review aims to provide a theoretical basis and support for the future mitigating and emergent treatment of the adverse effects of nanoparticles on sewage treatment systems.
Wastewater/toxicity* ; Sewage/chemistry* ; Zinc Oxide/chemistry* ; Waste Disposal, Fluid ; Nanoparticles/chemistry* ; Metal Nanoparticles/chemistry* ; Nitrogen/metabolism* ; Water Purification

The poor mechanical property and vulnerability to bacterial infections are the main problems in clinic for dental restoration resins. Based on this problem, the purpose of this study is to synthesize silver-titanium dioxide (Ag-TiO₂) nanoparticles with good photocatalytic properties, and add them to the composite resin to improve the mechanical properties and photocatalytic antibacterial capability of the resin. The microstructure and chemical composition of Ag-TiO₂ nanoparticles and composite resins were characterized. The results indicated that Ag existed in both metallic and silver oxide state in the Ag-TiO₂, and Ag-TiO₂ nanoparticles were uniformly dispersed in the resins. The results of mechanical experiments suggested that the mechanical properties of the composite resin were significantly improved due to the incorporation of Ag-TiO₂ nanoparticles. The antibacterial results indicated that the Ag-TiO₂ nanoparticle-filled composite resins exhibited excellent antibacterial activities under 660 nm light irradiation for 10 min due to the photocatalysis, and the Ag-TiO₂ nanoparticle-filled composite resins could also exhibit excellent antibacterial activities after contact with bacteria for 24 h without light irradiation because of the release of Ag ions. In summary, this study provides a new antibacterial idea for the field of dental composite resins.
Anti-Bacterial Agents/pharmacology* ; Composite Resins ; Metal Nanoparticles/chemistry* ; Nanoparticles ; Titanium/pharmacology*

8-hydroxy-2'-deoxyguanosine (8-OHdG) is a sensitive and stable biomarker for evaluating DNA oxidative damage. A rapid and sensitive colloidal gold immunochromatographic strip was developed for 8-OHdG detection by a competitive method. The sample pad (glass cellulose film), bonding pad (glass cellulose film), nitrocellulose film and absorbent pad were pasted on the polyvinyl chloride (PVC) base plate to construct the test strip. Colloidal gold (AuNPs) was prepared by the reduction of chloroauric acid with sodium citrate. 8-OHdG antibody (Ab) was coated on the outer layer of AuNPs to form Ab@AuNPs as a probe. Bovine serum albumin (BSA) and 8-OHdG were conjugated with carbodiimide hydrochloride to prepare an artificial antigen, which was used as the coating antigen of detection line. Goat anti mouse polyclonal antibody IgG was used as the coating antibody of control line. The experimental parameters were optimized including the type of nitrocellulose membrane, the formula of loading solution, and the spraying amount of gold labeled antibody. The results showed that the appropriate nitrocellulose membrane was CN 95. The optimal loading solution included BSA (1%), Tween-20 (3%), sucrose (3%) and NaCl (0.9%). The optimal spraying amount of gold labeled antibody was 4 μL. 8-OHdG can be detected by the strip under visible light, and the level of 8-OHdG in urine can be preliminarily determined by comparing the color intensity of T line and C line. The 8-OHdG concentration in urine was further calculated by the gray value of T line and the threshold of detection was 2.55 μg/L. This colloidal gold immunochromatographic strip is simple, rapid and specific for detecting 8-OHdG in human urine to preliminarily evaluate the human status.
8-Hydroxy-2'-Deoxyguanosine ; Animals ; Antibodies, Monoclonal ; Gold ; Gold Colloid/chemistry* ; Metal Nanoparticles ; Mice ; Sensitivity and Specificity

A magnetic metal organic framework (MMOF) was synthesized and used to separate Sr2+ in aqueous solution. The shape and structure of prepared Fe3O4@UiO-66-NH2 were characterized, and the absorbed concentration of strontium was determined through inductively coupled plasma mass spectrometry. The results indicated that Fe3O4 and UiO-66-NH2 combined through chemical bonding. The experimental adsorption results for separation of Sr2+ in aqueous solution indicated that the adsorption of Sr2+ to Fe3O4@UiO-66-NH2 increased drastically from pH 11 to pH 13. The adsorption isotherm model indicated that the adsorption of Sr2+ conformed to the Freundlich isotherm model (R2 = 0.9919). The MMOF thus inherited the superior qualities of magnetic composites and metal organic frameworks, and can easily be separated under an external magnetic field. This MMOF thus has potential applications as a magnetic adsorbent for low level radionuclide 90Sr.
Adsorption ; Ferrosoferric Oxide ; chemistry ; Hydrogen-Ion Concentration ; Metal-Organic Frameworks ; chemical synthesis ; chemistry ; Models, Theoretical ; Nanoparticles ; chemistry ; Strontium ; analysis ; Surface Properties ; Water Pollutants, Radioactive ; analysis ; Water Purification ; methods

OBJECTIVEThis paper aims to elucidate the combined toxicity of magnetite nanoparticles/Chromium [MNPs/Cr(VI)] adducts.

METHODSThe HEK293 cell was exposed to either Cr(VI) or MNPs, or their adducts MNPs/Cr(VI). The cytotoxicity was evaluated by assessing the cell viability, apoptosis, oxidative stress induction, and cellular uptake.

RESULTSThe toxicity of formed adducts is significantly reduced when compared to Cr(VI) anions. We found that the cellular uptake of MNPs/Cr(VI) adduct was rare, only few particles were endocytosed from the extracellular fluid and not accumulated in the cell nucleus. On the other hand, the Cr(VI) anions entered cells, generated oxidative stress, induced cell apoptosis, and caused cytotoxicity.

CONCLUSIONThe results showed minor effects of the nanoadducts on the tested cells and supported that magnetite nanoparticles could be implemented in the wastewater treatment process in which advantageous properties outweigh the risks.

Chromium ; chemistry ; toxicity ; Environmental Restoration and Remediation ; methods ; Ferrosoferric Oxide ; chemistry ; toxicity ; HEK293 Cells ; Humans ; Metal Nanoparticles ; chemistry ; toxicity

Biosynthesis of silver and other metallic nanoparticles is one of the emerging research area in the field of science and technology due to their potentiality, especially in the field of nano-biotechnology and biomedical sciences in order to develop nanomedicine. In our present study, Penicillium decumbens (MTCC-2494) was brought from Institute of Microbial Technology (IMTECH) Chandigarh and employed for extracellular biological synthesis of silver nanoparticles. Ag-NPs formation was appeared with a dark brown color inside the conical flask. Characterization of Ag-NPs were done by UV-Spectrophotometric analysis which showed absorption peak at 430 nm determines the presence of nanoparticles, Fourier transform infrared (FT-IR) spectroscopic analysis, showed amines and amides are the possible proteins involved in the stabilization of nanoparticles as capping agent. Atomic force Microscopy (AFM) confirmed the particle are spherical, size was around 30 to 60 nm and also the roughness of nanoparticles. Field emission scanning electron microscopy (FE-SEM) showed the topology of the nanoparticles and were spherical in shape. The biosynthesis process was found fast, ecofriendly and cost effective. Nano-silver particle was found to have a broad antimicrobial activity and also it showed good enhancement of antimicrobial activity of Carbenicillin, Piperacillin, Cefixime, Amoxicillin, Ofloxacin and Sparfloxacin in a synergistic mode. These Ag-NPs showed good anti-cancer activity at 80 μg·mL(-1)upon 24 hours of incubation and toxicity increases upon 48 hours of incubation against A-549 human lung cancer cell line and the synergistic formulation of the antibiotic with the synthesized nanoparticles was found more effective against the pathogenic bacteria studied.
Anti-Bacterial Agents ; metabolism ; pharmacology ; Antineoplastic Agents ; metabolism ; pharmacology ; Bacteria ; drug effects ; Cell Line, Tumor ; Humans ; Lung Neoplasms ; drug therapy ; Metal Nanoparticles ; chemistry ; Microbial Sensitivity Tests ; Penicillium ; metabolism ; Silver ; metabolism ; pharmacology

BACKGROUND: The bacterium Chlamydia trachomatis is one of the leading causes of sexually transmitted diseases worldwide. Since no simple and effective tool exists to diagnose C. trachomatis infections, we evaluated a novel point-of-care (POC) test, aQcare Chlamydia TRF kit, which uses europium-chelated nanoparticles and a time-resolved fluorescence reader. METHODS: The test performance was evaluated by comparing the results obtained using the novel POC testing kit with those obtained using a nucleic acid amplification test (NAAT), using 114 NAAT-positive and 327 NAAT-negative samples. RESULTS: The cut-off value of the novel test was 20.8 with a detection limit of 0.27 ng/mL. No interference or cross-reactivity was observed. Diagnostic accuracy showed an overall sensitivity of 93.0% (106/114), specificity of 96.3% (315/327), positive predictive value (PPV) of 89.8% (106/118), and negative predictive value (NPV) of 97.5% (315/323). The sensitivity of the novel test was much higher than that of currently available POC tests. Furthermore, the relative ease and short turnaround time (30 min) of this assay enables C. trachomatis-infected individuals to be treated without a diagnostic delay. CONCLUSIONS: This simple and novel test is a potential tool to screen a larger population, especially those in areas with limited resources.
Adult ; Aged ; Aged, 80 and over ; Chlamydia Infections/*diagnosis ; Chlamydia trachomatis/*genetics/isolation & purification ; DNA, Bacterial/chemistry/metabolism ; Europium/*chemistry ; Female ; Humans ; Male ; Metal Nanoparticles/*chemistry ; Middle Aged ; Point-of-Care Systems ; Reagent Kits, Diagnostic ; Real-Time Polymerase Chain Reaction ; Sensitivity and Specificity ; Young Adult

Due to the good tumor-targeting and excellent biocompatibility, the drug-loading nanoparticles (NPs) has been widely applied in the diagnosis and treatment of cancer. However, after the NPs are recognized and internalized by cancer cells, the effects of NPs on cell migration behavior were unclear. In the present study, the self-assembly techniques (SAMs) was used to modify gold (Au) nanoparticles (Au NPs) with different chemical functional groups (CH3, OH, COOH and NH2) as model NPs. The dispersion of these groups in solution and the distribution in cells were studied by transmission electron microscope (TEM), respectively, and the proliferation was examined by MTT assay in vitro. The wound-healing and the Transwell assay were used to examine the effect of internalized Au-NPs on HepG2 cells migration. The results showed that different Au-NPs mainly distributed at the edge of the vesicle membrane and the gap between cells. The Au-NPs resulted in decreased cell viability in a concentration-depended manner. In addition, the results of wound-healing and Transwells assay indicated that the internalization of the NH2-NPs and OH-NPs would inhibit cell migration compared with those in the control group.
Carcinoma, Hepatocellular ; metabolism ; Cell Movement ; Cell Proliferation ; Cell Survival ; Gold ; Hep G2 Cells ; Humans ; Liver Neoplasms ; metabolism ; Metal Nanoparticles ; chemistry

OBJECTIVES: With recent advances in nanoparticle manufacturing and applications, potential exposure to nanoparticles in various settings is becoming increasing likely. No investigation has yet been performed to assess whether respiratory tract exposure to cerium oxide (CeO2) nanoparticles is associated with alterations in protein signaling, inflammation, and apoptosis in rat lungs. METHODS: Specific-pathogen-free male Sprague-Dawley rats were instilled with either vehicle (saline) or CeO2 nanoparticles at a dosage of 7.0 mg/kg and euthanized 1, 3, 14, 28, 56, or 90 days after exposure. Lung tissues were collected and evaluated for the expression of proteins associated with inflammation and cellular apoptosis. RESULTS: No change in lung weight was detected over the course of the study; however, cerium accumulation in the lungs, gross histological changes, an increased Bax to Bcl-2 ratio, elevated cleaved caspase-3 protein levels, increased phosphorylation of p38 MAPK, and diminished phosphorylation of ERK-1/2-MAPK were detected after CeO2 instillation (p<0.05). CONCLUSIONS: Taken together, these data suggest that high-dose respiratory exposure to CeO2 nanoparticles is associated with lung inflammation, the activation of signaling protein kinases, and cellular apoptosis, which may be indicative of a long-term localized inflammatory response.
Animals ; Apoptosis/*drug effects ; Caspase 3/metabolism ; Cerium/chemistry ; Inflammation ; Lung/*drug effects/metabolism/pathology ; Male ; Metal Nanoparticles/chemistry/*toxicity ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; Mitogen-Activated Protein Kinases/*metabolism ; Phosphorylation/drug effects ; Proto-Oncogene Proteins c-bcl-2/metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction/*drug effects ; bcl-2-Associated X Protein/metabolism ; p38 Mitogen-Activated Protein Kinases/metabolism