Impact of metal oxide nanoparticles on cotton(Gossypium hirsutum L.):a physiological perspective

Cotton production substantiated a crucial part in the escalating economic development of many countries.To realize the increasing global demand for cotton,the emphasis should be laid on to improve cotton fiber growth and production.The bioengineered transgenic cotton proved expedient in resolving inadequacies of conventional cotton,but still required improvements to encounter heightened demand of textile industries.One possible solution pertaining to this has been provided by nanoscience in the form of metal or metal oxide nanoparticles.These metal oxide nanoparticles have easy access to the various parts of cotton plants through its transportation system,and thus significantly influence several parameters relative to the growth and production of cotton fiber.This review summarizes the distribution and accumulation of metal oxide nanoparticles in cotton plant and its impact on different plant growth-promoting factors,which resulted in the improved cotton yields.

Determination of the mechanism of photoinduced toxicity of selected metal oxide nanoparticles(ZnO,CuO,Co_3O_4 and TiO_2)to E.coli bacteria

Cytotoxicity of selected metal oxide nanoparticles（MNPs）（ZnO,CuO,Co 3 O 4 and TiO 2）was investigated in Escherichia coli both under light and dark conditions.Cytotoxicity experiments were conducted with spread plate counting and the LC 50 values were calculated.We determined the mechanism of toxicity via measurements of oxidative stress,reduced glutathione,lipid peroxidation,and metal ions.The overall ranking of the LC 50 values was in the order of ZnO 〈 CuO 〈 Co 3 O 4 〈 TiO 2 under dark condition and ZnO 〈 CuO 〈 TiO 2 〈 Co 3 O 4 under light condition.ZnO MNPs were the most toxic among the tested nanoparticles.Our results indicate depletion of reduced glutathione level and elevation of malondialdehyde level correlated with the increase in oxidative stress.Released metal ions were found to have partial effect on the toxicity of MNPs to E.coli.In summary,the dynamic interactions of multiple mechanisms lead to the toxicity of the tested MNPs to E.coli.

Precipitation of metal oxide nanoparticles using a miniemulsion technique

A method to precipitate nanoparticles using a miniemulsion technique is described, in which miniemulsion droplets between 100 and 1000 nm in size serve as nanoreactors enabling both the control of particle formation and particle growth. The application of miniemulsion droplets to synthesise nanoparticles comprises three advantages： first, the size of the precipitated particles is limited by the reactant concentration within the emulsion droplet; second, particle agglomeration is prevented as nanoparticle collision outside the nanoreactor is avoided; and third, easy technical scale up can be realized by increasing emulsion volume and thus the number of nanoreactors, while local conditions within the reactors are not changed, The miniemulsion technique is an easy scalable process which allows defined synthesis of particles by precipitation reactions. The miniemulsion technique involves first the preparation of a stable water-in- oil miniemulsion by high pressure homogenisation. Whereas a water soluble reactant is provided within the aqueous droplets, another oilas well as water-soluble reactant can be introduced to the emulsion after homogenisation. The precipitation reaction is induced by the diffusion of the second reactant into the emulsion droplet. Together with this contribution, a method is described and discussed which uses a high pressure homogenisation process to produce stable water-in-oil miniemulsions serving as a reaction medium to precipitate metal oxides.

ZnO,TiO_2,SiO_2,and Al_2O_3 Nanoparticles-induced Toxic Effects on Human Fetal Lung Fibroblasts

Objective This study aims to investigate and compare the toxic effects of four types of metal oxide （ZnO, TiO2, SiO2, and Al2O3） nanoparticles with similar primary size （-20 nm） on human fetal lung fibroblasts （HFL1） in vitro.Methods The HFL1 cells were exposed to the nanoparticles, and toxic effects were analyzed by using MTT assay, cellular morphology observation and Hoechst 33 258 staining.Results The results show that the four types of metal oxide nanoparticles lead to cellular mitochondrial dysfunction, morphological modifications and apoptosis at the concentration range of 0.25-1.50 mg/mL and the toxic effects are obviously displayed in dose-dependent manner. ZnO is the most toxic nanomaterials followed by TiO2, SiO2, and Al2O3 nanoparticles in a descending order.Conclusion The results highlight the differential cytotoxicity associated with exposure to ZnO, TiO2, SiO2, and Al2O3 nanoparticles, and suggest an extreme attention to safety utilization of these nanomaterials.

Bioaccumulation and effects of sediment-associated gold-and graphene oxide nanoparticles on Tubifex tubifex

With the development of nanotechnology,gold（Au） and graphene oxide（GO） nanoparticles have been widely used in various fields,resulting in an increased release of these particles into the environment.The released nanoparticles may eventually accumulate in sediment,causing possible ecotoxicological effects to benthic invertebrates.However,the impact of Au-NPs and GO-NPs on the cosmopolitan oligochaete,Tubifex tubifex,in sediment exposure is not known.Mortality,behavioral impact（GO-NP and Au-NP） and uptake（only Au-NP） of sediment-associated Au-NPs（4.9±0.14 nm） and GO-NPs（116±0.05 nm） to T.tubifex were assessed in a number of 5-day exposure experiments.The results showed that the applied Au-NP concentrations（10 and 60 μg Au/g dry weight sediment） had no adverse effect on T.tubifex survival,while Au bioaccumulation increased with exposure concentration.In the case of GO-NPs,no mortality of T.tubifex was observed at a concentration range of 20 and180 μg GO/g dry weight sediment,whereas burrowing activity was significantly reduced at 20 and 180 μg GO/g dry weight sediment.Our results suggest that Au-NPs at 60 μg Au/g or GO-NPs at 20 and 180 μg GO/g were detected by T.tubifex as toxicants during short-term exposures.

Nanoreactors derived from silica-protection-assisted metal-organic framework

The construction of highly stable and regular nanoreactors is a major challenge.In this work,we use a facile template protection method to obtain ZIF-67@SiO2(JS) and to encapsulate metal oxide nanoparticles(Co3O4) into nanoreactors(SiO2).ZIF-67 crystals provide a cobalt species;SiO2 was first used as a protective layer of ZIF-67 and then as a nanoreactor for metastable metal oxide nanoparticles.On this basis,Co3O4@SiO2 with dodecahedron morphology were synthesized by calcining JS at different tempe ratures,followed by a hydrothermal reaction to obtain Co3(OH)4Si2O5.Subsequently,CoSx and CoP-SiO2 were fabricated through sulfuration and phosphorization.The results in this work show that nanoreactors derived from metal-organic frameworks(MOFs) with a rational structure have broad development prospects.

Catheters coated with Zn-doped CuO nanoparticles delay the onset of catheter-associated urinary tract infections

Catheter-associated urinary tract infections （CAUTIs） are among the most common bacterial infections associated with medical devices. In the current study, the synthesis, coating, antibiofilm properties, and biocompatibility of urinary catheters coated with Zn-doped CuO （Zn0.12Cu0.880） nanoparticles （NPs） were examined. The doped NPs were synthesized and subsequently deposited on the catheter by the sonochemical method. The coated catheters displayed high antibiofilm activity and promising biocompatibility, as indicated by low in vitro cytotoxicity, negligible associated cytokine secretion, and absence of detectable irritation. The biocompatibility and ability of the Zn-doped CuO coating to inhibit biofilm formation were also evaluated in vivo using a rabbit model. Rabbits catheterized with uncoated catheters scored positive for CAUTI by day 4 of the experiment. In contrast, rabbits catheterized with Zn-doped CuO-coated catheters did not exhibit CAUTI until day 7 or remained completely uninfected for the whole duration of the 7-day experiment. Furthermore, the in vivo biocompatibility assays and examinations supported the biosafety of Zn-doped CuO-coated catheters. Taken together, these data highlight the potential of Zn-doped CuO nanocomposite as effective antibiofilm compound.

Synthesis of Cu3.8Ni/CoO and Cu3.8Ni/MnO nanoparticles for advanced lithium-ion battery anode materials

We synthesized Cu3.8Ni/CoO and Cu3.8Ni/MnO nanoparticles via an easy and scalable solution synthesis. The synthesized Cu3.8Ni/CoO and Cu3.8Ni/MnO nano- particles were annealed to remove the organic surfactants without phase transitions or side reactions. Electrons can be transferred via metallic Cu3.8Ni, which will not react with lithium ions. The heterogeneous structures of Cu3.8Ni/CoO and Cu3.8Ni/MnO nanopartides could enhance the lithium ion mobility and improve the life cycle, and these materials are therefore promising candidates as high- power-density and high-energy-density anode materials for lithium-ion batteries in diverse applications, such as electrical vehicles.

Stable isotope labeling of nanomaterials for biosafety evaluation and drug development

Quantitative information,such as environmental migration,absorption,biodistribution,biotransformation,and elimination,is fundamental and essential for the nanosafety evaluations of nanomaterials.Due to the complexity of biological and environmental systems,it is challenging to develop quantitative approaches and tools that could characterize intrinsic behaviors of nanomaterials in the organisms.The isotopic tracers are ideal candidates to tune the physical properties of nanomaterials while preserving their chemical properties.In this review article,we summarized the stable isotope labeling methods of nanomaterials for evaluating their environmental and biological effects.The skeleton labeling protocols of carbon nanomaterials and metal/metal oxide nanoparticles were introduced.The advantages and disadvantages of stable isotope labeling were discussed in comparison with other quantitative methods for nanomaterials.The quantitative information of nanomaterials in environmental and biological systems was summarized along with the biosafety data.The benefits for drug development of nanomedicine were analyzed based on the targeting effects,persistent accumulation,and safety.Finally,the challenges and future perspectives of stable isotope labeling in nanoscience and nanotechnology were discussed.