Enhanced Bacterial Growth by Polyelemental Glycerolate Particles.

While polyelemental alloys are shown to be promising for healthcare applications, their effectiveness in promoting bacterial growth remains unexplored. In the present work, we evaluated the interaction of polyelemental glycerolate particles (PGPs) with Escherichia coli (E. coli) bacteria. PGPs were synthesized using the solvothermal route, and nanoscale random distribution of metal cations in the glycerol matrix of PGPs was confirmed. We observed 7-fold growth of E. coli bacteria upon 4 h of interaction with quinary glycerolate (NiZnMnMgSr-Gly) particles in comparison to control E. coli bacteria. Nanoscale microscopic studies on bacteria interactions with PGPs showed the release of metal cations in the bacterium cytoplasm from PGPs. The electron microscopy imaging and chemical mapping indicated bacterial biofilm formation on PGPs without causing significant cell membrane damage. The data showed that the presence of glycerol in PGPs is effective in controlling the release of metal cations, thus preventing bacterial toxicity. The presence of multiple metal cations is expected to provide synergistic effects of nutrients needed for bacterial growth. The present work provides key microscopic insights of mechanisms by which PGPs enhance biofilm growth. This study opens the door for future applications of PGPs in areas where bacterial growth is essential including healthcare, clean energy, and the food industry.

In Situ Microscopic Studies on the Interaction of Multi-Principal Element Nanoparticles and Bacteria.

Multi-principal element nanoparticles are an emerging class of materials with potential applications in medicine and biology. However, it is not known how such nanoparticles interact with bacteria at nanoscale. In the present work, we evaluated the interaction of multi-principal elemental alloy (FeNiCu) nanoparticles with Escherichia coli (E. coli) bacteria using the in situ graphene liquid cell (GLC) scanning transmission electron microscopy (STEM) approach. The imaging revealed the details of bacteria wall damage in the vicinity of nanoparticles. The chemical mappings of S, P, O, N, C, and Cl elements confirmed the cytoplasmic leakage of the bacteria. Our results show that there is selective release of metal ions from the nanoparticles. The release of copper ions was much higher than that for nickel while the iron release was the lowest. In addition, the binding affinity of bacterial cell membrane protein functional groups with Cu, Ni, and Fe cations is found to be the driving force behind the selective metal cations' release from the multi-principal element nanoparticles. The protein functional groups driven dissolution of multielement nanoparticles was evaluated using the density functional theory (DFT) computational method, which confirmed that the energy required to remove Cu atoms from the nanoparticle surface was the least in comparison with those for Ni and Fe atoms. The DFT results support the experimental data, indicating that the energy to dissolve metal atoms exposed to oxidation and/or the to presence of oxygen atoms at the surface of the nanoparticle catalyzes metal removal from the multielement nanoparticle. The study shows the potential of compositional design of multi-principal element nanoparticles for the controlled release of metal ions to develop antibacterial strategies. In addition, GLC-STEM is a promising approach for understanding the nanoscale interaction of metallic nanoparticles with biological structures.

Unveiling growth and dynamics of liposomes by graphene liquid cell-transmission electron microscopy.

Liposome is a model system for biotechnological and biomedical purposes spanning from targeted drug delivery to modern vaccine research. Yet, the growth mechanism of liposomes is largely unknown. In this work, the formation and evolution of phosphatidylcholine-based liposomes are studied in real-time by graphene liquid cell-transmission electron microscopy (GLC-TEM). We reveal important steps in the growth, fusion and denaturation of phosphatidylcholine (PC) liposomes. We show that initially complex lipid aggregates resembling micelles start to form. These aggregates randomly merge while capturing water and forming small proto-liposomes. The nanoscopic containers continue sucking water until their membrane becomes convex and free of redundant phospholipids, giving stabilized PC liposomes of different sizes. In the initial stage, proto-liposomes grow at a rate of 10-15 nm s-1, which is followed by their growth rate of 2-5 nm s-1, limited by the lipid availability in the solution. Molecular dynamics (MD) simulations are used to understand the structure of micellar clusters, their evolution, and merging. The liposomes are also found to fuse through lipid bilayers docking followed by the formation of a hemifusion diaphragm and fusion pore opening. The liposomes denaturation can be described by initial structural destabilization and deformation of the membrane followed by the leakage of the encapsulated liquid. This study offers new insights on the formation and growth of lipid-based molecular assemblies which is applicable to a wide range of amphiphilic molecules.

The potential beneficial effects of education and familiarity with cesarean section procedure and the operating room environment on promotion of anxiety and pain intensity: A randomized controlled clinical trial.

BACKGROUND: Anxiety before and pain intensity after cesarean section is among the factors that should be taken into consideration among the candidates for cesarean section. The present study aimed to investigate the effect of familiarity with cesarean section and the operating room environment on anxiety and pain intensity among the mothers undergoing cesarean section. METHODS: This clinical trial was conducted on 80 women referred to the hospitals affiliated to Shiraz University of Medical Sciences for cesarean section in 2018. The participants were randomly divided into a control (n = 40) and an intervention group (n = 40). The intervention group took part in four educational sessions, while the control group received the hospital's routine care. The Beck Anxiety Inventory was completed by the two groups before and after the intervention. The McGill Pain Questionnaire was also filled out by the two groups in the ward after the cesarean section. After all, the data were entered into the SPSS software, version 21, and were analyzed using independent t-test and ANCOVA. RESULTS: The results showed no significant difference between the two groups regarding the mean score of anxiety prior to the intervention. After the intervention, the mean score of anxiety was 7.98 ± 3.77 in the intervention group and 19.70 ± 6.45 in the control group, and the difference was statistically significant (P < 0.0001). Indeed, the mean intensity of pain was 43.98 ± 7.63 in the intervention group and 57.75 ± 10.69 in the control group after the intervention, and the difference was statistically significant (P < 0.017). CONCLUSION: The patients' familiarity with cesarean section and the operating room environment caused a decline in the anxiety level prior to cesarean section as well as a decrease in the score of pain after the operation. Hence, midwives and nurses have to play effective roles in decreasing pregnant women's anxiety and pain through identification of strategies for empowering them and managing their worries.

Assessment of neuro behavioral disorders in workers exposed to organic solvents in a publication house.

BACKGROUND: Organic solvents are known as a group of organic compounds, widely used in industry and to which many workers are exposed. Neurotoxicity is one of the most important complications of the chronic exposure to the solvents and may causes neurobehavioral disorders in workers. We have studied the frequency of neurobehavioral disorders in workers exposed to organic solvents in one of the publishing houses in Tehran. METHODS: In this cross-sectional study, 510 workers of a publishing house, having been employed at least a year before the research, were selected to be studied. Among them, 345 workers had been exposed to organic solvents and the other (165 workers) had not. Data were collected using a questionnaire. This questionnaire included demographic and occupational information, and the Swedish Q16 questionnaire. Variables included age, duration of employment, working shift, and smoking. Then we compared both groups in terms of neurobehavioral disorders, using statistical methods. RESULTS: The mean score of the Swedish Q16 questionnaire in the exposed group (4.8±4.4) was significantly higher than the non-exposed group (3.2±3.1) (p=0.001). According to the questionnaire score, the frequency of neurobehavioral disorders in the exposed group was 38% and in the non-exposed group was 22% (p=0.001). We estimated that the frequency of neurobehavioral disorders in the exposed group was significantly higher than the non-exposed group (p<0.05) using regression analysis and removal of the confounding factors. CONCLUSION: This study shows that the frequency of the neurobehavioral disorders in the exposed group is significantly higher than the non-exposed group.