The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred to as the 'personalized protein corona'). In this study, we demonstrate that graphene oxide (GO) sheets can trigger different biological responses in the presence of coronas obtained from various types of diseases. GO sheets were incubated with plasma from human subjects with different diseases/conditions, including hypofibrinogenemia, blood cancer, thalassemia major, thalassemia minor, rheumatism, fauvism, hypercholesterolemia, diabetes, and pregnancy. Identical sheets coated with varying protein corona decorations exhibited significantly different cellular toxicity, apoptosis, and uptake, reactive oxygen species production, lipid peroxidation and nitrogen oxide levels. The results of this report will help researchers design efficient and safe, patient-specific nano biomaterials in a disease type-specific manner for clinical and biological applications.
The application of Fe3 O4 nanoparticles to the separation of desulfurizing bacterial cells and their influence on the desulfurization activity and reusability of the two bacterial strains Rhodococcus erythropolis FMF and R. erythropolis IGTS8 were investigated. Magnetite nanoparticles were synthesized via the reverse coprecipitation method. Transmission electron microscopy (TEM) images showed that the magnetite nanoparticles had sizes of 5.35 ± 1.13 (F1 nanoparticles) and 8.74 ± 1.18 nm (F2 nanoparticles) when glycine was added during the synthesis of nanoparticles and when it was absent from the reaction mixture, respectively. Glycine was added after the synthesis of both F1 and F2 nanoparticles to stabilize the nanoparticle dispersion. TEM images of cells treated with magnetite nanoparticles indicated that F1 nanoparticles were immobilized on the surface of bacterial cells more evenly than the F2 nanoparticles. Desulfurization activities of the F1 magnetite nanoparticle-coated R. erythropolis FMF and R. erythropolis IGTS8 cells (with sulfur-removal percentage values of 70 ± 4 and 73 ± 3, respectively), as examined with the spectrophotometric Gibbs assay (based on dibenzothiophene degradation and sulfur-removal percentage), were not significantly different from those for the free bacterial cells (67 ± 3 and 69 ± 4, respectively). These results indicate that magnetite nanoparticles cannot affect the desulfurization activity of cells examined in this work. Isolation of bacterial cells from the suspension using a magnet and evaluation of desulfurization activity of separated cells showed that Fe3 O4 nanoparticles can provide a high-efficiency recovery of bacterial cells from a suspension, with the reused magnetite nanoparticle-coated bacterial cells being able to maintain their desulfurization activity efficiently.
Background: Magnetite (Fe3O4) nanoparticles are currently one of the important and acceptable magnetic nanoparticles for biomedical applications. To use magnetite nanoparticles for bacteria cell separation, the surface of nanoparticles would be modified for immobilizing of nanoparticles on the surface of bacteria. Functionalization of magnetite nanoparticles is performed by different surfactants such as glycine or oleic acid to attach on the bacteria cell surface simultaneously. The magnetic nanoparticles have very low toxicity on the living cells. There are some studies on evaluating the toxicity of magnetite nanoparticles on eukaryote cells, which their results showed negligible toxicity in eukaryote cells of the modified magnetite nanoparticles with different surfactants. But the toxicity of magnetite nanoparticles on bacteria cells is not reported. Objectives: in this study, the effect of the magnetic nanoparticles iron oxide (Fe3O4) on the growth rate of the genetically engineered Pseudomonas aeruginosa (PTSOX4) cells in different media with different magnetic nanoparticles concentration have been investigated. Materials and Methods: In this study, the genetically manipulated bacterial cells, Pseudomonas aeruginosa (PTSOX4), were coated with magnetic Fe3O4 nanoparticles to evaluate the toxicity effect of these nanoparticles on the growth rate of this strain in Laurial Bertany (LB) and Basal Salt media (BSM) separately. In addition the minimal inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) tests of these nanoparticles were examined. Results: A low concentration of nanoparticles has little toxicity effect on the cell growth in this bacterium. Maximal level of the growth obtained in the late stationary phase, using a concentration of 500 ppm or more of Fe3O4 nanoparticles, but a high concentration of these nanoparticles, more than 1000 PPM, resulted in reducing the cell growth rate. However, there was not a considerable lethal effect on the cell viability. Moreover, using a high nanoparticle concentration leads to a high level of bacterial cell coating due to more contact of the nanoparticles to bacterial cell surface. Conclusions: It is concluded that magnetite nanoparticles have negligible toxicity on the living bacteria cells and they are so applicable in different parts of biotechnology fields.
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