Exploring multiple effects of Zn0.15Mg0.85O nanoparticles on Bacillus subtilis and macrophages.

The increasing number of multidrug resistant bacteria raises a serious public-health concern, which is exacerbated by the lack of new antibiotics. Metal oxide nanoparticles are already applied as an antibacterial additive in various products used in everyday life but their modes of action have remained unclear. Moreover, their potential negative effects to human health are still under evaluation. We explored effects of mixed metal oxide Zn0.15Mg0.85O on Bacillus subtilis, as a model bacterial organism, and on murine macrophages. Zn0.15Mg0.85O killed planktonic bacterial cells and prevented biofilm formation by causing membrane damages, oxidative stress and metal ions release. When exposed to a sub-inhibitory amount of Zn0.15Mg0.85O, B. subtilis up-regulates proteins involved in metal ions export, oxidative stress response and maintain of redox homeostasis. Moreover, expression profiles of proteins associated with information processing, metabolism, cell envelope and cell division were prominently changed. Multimode of action of Zn0.15Mg0.85O suggests that no single strategy may provide bacterial resistance. Macrophages tolerated Zn0.15Mg0.85O to some extend by both the primary phagocytosis of nanoparticles and the secondary phagocytosis of damaged cells. Bacterial co-treatment with ciprofloxacin and non-toxic amount of Zn0.15Mg0.85O increased antibiotic activity towards B. subtilis and E. coli.

Regenerative Core-Shell Nanoparticles for Simultaneous Removal and Detection of Endotoxins.

Detection and removal of lipopolysaccharides (LPS) from food and pharmaceutical preparations is important for their safe intake and administration to avoid septic shock. We have developed an abiotic system for reversible capture, removal, and detection of LPS in aqueous solutions. Our system comprises long C18 acyl chains tethered to Fe3O4/Au/Fe3O4 nanoflowers (NFs) that act as solid supports during the separation process. The reversible LPS binding is mediated by facile hydrophobic interactions between the C18 chains and the bioactive lipid A component present on the LPS molecule. Various parameters such as pH, solvent, sonication time, NF concentration, alkane chain length, and density are optimized to achieve a maximum LPS capture efficiency. The NFs can be reused at least three times by simply breaking the NF-LPS complexes in the presence of food-grade surfactants, making the entire process safe, efficient, and scalable. The regenerated particles also serve as colorimetric labels in dot blot bioassays for simple and rapid estimation of the LPS removed.

Pure and multi metal oxide nanoparticles: synthesis, antibacterial and cytotoxic properties.

Th antibacterial activity of metal oxide nanoparticles has received marked global attention as they can be specifically synthesized to exhibit significant toxicity to bacteria. The importance of their application as antibacterial agents is evident keeping in mind the limited range and effectiveness of antibiotics, on one hand, and the plethora of metal oxides, on the other, along with the propensity of nanoparticles to induce resistance being much lower than that of antibiotics. Effective inhibition against a wide range of bacteria is well known for several nano oxides consisting of one metal (Fe3O4, TiO2, CuO, ZnO), whereas, research in the field of multi-metal oxides still demands extensive exploration. This is understandable given that the relationship between physicochemical properties and biological activity seems to be complex and difficult to generalize even for metal oxide nanoparticles consisting of only one metal component. Also, despite the broad scope that metal oxide nanoparticles have as antibacterial agents, there arise problems in practical applications taking into account the cytotoxic effects. In this respect, the consideration of polymetallic oxides for biological applications becomes even greater since these can provide synergetic effects and unify the best physicochemical properties of their components. For instance, strong antibacterial efficiency specific of one metal oxide can be complemented by non-cytotoxicity of another. This review presents the main methods and technological advances in fabrication of nanostructured metal oxides with a particular emphasis to multi-metal oxide nanoparticles, their antibacterial effects and cytotoxicity.

Ambivalent Outcomes of Cell Apoptosis: A Barrier or Blessing in Malaria Progression.

The life cycle of Plasmodium in two evolutionary distant hosts, mosquito, and human, is a complex process. It is regulated at various stages of developments by a number of diverged mechanisms that ultimately determine the outcome of the disease. During the development processes, Plasmodium invades a variety of cells in two hosts. The invaded cells tend to undergo apoptosis and are subsequently removed from the system. This process also eliminates numerous parasites along with these apoptotic cells as a part of innate defense against the invaders. Plasmodium should escape the invaded cell before it undergoes apoptosis or it should manipulate host cell apoptosis for its survival. Interestingly, both these phenomena are evident in Plasmodium at different stages of development. In addition, the parasite also exhibits altruistic behavior and triggers its own killing for the selection of the best 'fit' progeny, removal of the 'unfit' parasites to conserve the nutrients and to support the host survival. Thus, the outcomes of cell apoptosis are ambivalent, favorable as well as unfavorable during malaria progression. Here we discuss that the manipulation of host cell apoptosis might be helpful in the regulation of Plasmodium development and will open new frontiers in the field of malaria research.