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.

A Smart Lithium Battery with Shape Memory Function.

Rapidly growing flexible and wearable electronics highly demand the development of flexible energy storage devices. Yet, these devices are susceptible to extreme, repeated mechanical deformations under working circumstances. Herein, the design and fabrication of a smart, flexible Li-ion battery with shape memory function, which has the ability to restore its shape against severe mechanical deformations, bending, twisting, rolling or elongation, is reported. The shape memory function is induced by the integration of a shape-adjustable solid polymer electrolyte. This Li-ion battery delivers a specific discharge capacity of ≈140 mAh g-1 at 0.2 C charge/discharge rate with ≈92% capacity retention after 100 cycles and ≈99.85% Coulombic efficiency, at 20 °C. Besides recovery from mechanical deformations, it is visually demonstrated that the shape of this smart battery can be programmed to adjust itself in response to an internal/external heat stimulus for task-specific and advanced applications. Considering the vast range of available shape memory polymers with tunable chemistry, physical, and mechanical characteristics, this study offers a promising approach for engineering smart batteries responsive to unfavorable internal or external stimulus, with potential to have a broad impact on other energy storage technologies in different sizes and shapes.

Thymol, cardamom and Lactobacillus plantarum nanoparticles as a functional candy with high protection against Streptococcus mutans and tooth decay.

Due to the increasing resistance of microorganisms against antibiotics, the use of natural bioactive substances for the prevention of pathogenic bacteria is considered in food products. In this study, thymol, cardamom essential oil, L. plantarum cell-free supernatant (ATCC 14917), and their nanoparticle candies prepared and inhibition activities against S. mutans (ATCC 25175), which is important in causing tooth decay, was investigated. Moisture content, pH, and sensory analyzes of candies measured. Also, SEM and FTIR of treated candy samples were performed. All examined bioactive substances and their nanoparticles showed an inhibitory effect against S. mutans with different minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The prepared candies had pH 5.5 represented a bactericidal effect against S. mutans. SEM and FTIR results approved the antibacterial effects of prepared candies. According to the results, all of the prepared candies significantly decreased S. mutans in saliva compared to the control candy and they are suitable agents for S. mutans growth-inhibiting. Also, cardamom essential oil candy showed the most general acceptance in a sensory analysis by panelists.

Superparamagnetic MOF@GO Ni and Co based hybrid nanocomposites as efficient water pollutant adsorbents.

A series of highly efficient adsorbents were developed using Ni3(BTC)2 and Co3(BTC)2 metal-organic frameworks (MOFs) and Fe3O4 magnetic nanoparticles (MNPs) to functionalize graphene oxide (GO). XRD results show high crystallinity of the prepared nanomaterials and the successful decoration of Ni3(BTC)2 and Co3(BTC)2 MOFs over the GO substrate (BTC = benzene-1,3,5-tricarboxylic acid). SEM and TEM imaging show the successful formation of nanoscale MOFs and Fe3O4 MNPs over GO. IR spectroscopy supports the characterization and successful preparation of the Fe3O4/MOF@GO hybrid composite nanoadsorbents. The prepared composite nanoadsorbents were used to sorb Methylene Blue (MB) as a model for common organic pollutants in water and common ions (Na+, Ca2+, Mg2+, SO42-, SiO32-) from a brackish water model. The adsorbed concentration at equilibrium of MB of the prepared composite nanoadsorbents increases by an average of 30.52 and 13.75 mg/g for the Co and Ni composite, respectively, when compared to the MOFs parent materials. The adsorbed amount of sulfate ions increases by 92.1 mg/g for the Co composite and 112.1 mg/g for the Ni composite, when compared to graphene oxide. This adsorption enhancement is attributed to suppressed aggregation through increased dispersive forces in the MOFs due to the presence of GO, formation of nanoscale MOFs over the GO platform, and the hindering of stacking of the graphene layers by the MOFs. Leaching tests show that the release of Co and Ni ions to water is reduced from 105.2 and 220 mg/L, respectively, in the parent MOF materials to 0.5 and 16.4 mg/L, respectively, in the composite nanoadsorbents. These findings show that the newly developed composite nanoadsorbents can sorb organic pollutants, and target sulfate and silicate anions, which makes them suitable candidates for water and wastewater treatments.

Nanoscale nickel metal organic framework decorated over graphene oxide and carbon nanotubes for water remediation.

In this report, highly crystalline and well-dispersed nano-sized nickel metal organic framework (MOFs) was decorated over graphene oxide (GO) and carbon nanotubes (CNTs) platforms to form hybrid nanocomposites. These as-synthesized hybrid nanocomposites were synthesized through a one-pot green solvothermal method. The prepared nanocomposites were characterized by SEM, TEM, EDS, XRD, FT-IR, Raman and TGA techniques. XRD analysis revealed the crystalline structure of the hybrid nanocomposites. Morphological and elemental studies also verified successful decoration of nickel-benzene dicarboxylate (Ni-BDC) MOFs over GO and CNT platforms. Chemical analysis collected through IR, and thermal analysis collected through TGA technique, illustrated the presence of all the components in the hybrid nanomaterials. Methylene blue (MB) was used as a model organic pollutant to analyze the adsorption capacity of the prepared nanocomposites. According to the findings, a strong interaction exists between the MB molecule and the developed adsorbents at which due to the synergistic effect, the hybrid nanocomposites show several times higher adsorption capacity compared to that of parent materials. This improvement can be due to several reasons: high surface area of the MOFs in the composites resulting from the smaller size of MOFs, presence of the pores formed between the MOFs and the platforms and different morphological characteristic of Ni-BDC MOFs in hybrid nanocomposites, compared to bare Ni-BDC MOFs. Furthermore, the isotherm and kinetic studies revealed that the adsorption of MB onto the newly prepared adsorbents could best be explained by the Langmuir and Pseudo-second order kinetic models. A regeneration study demonstrated the highly stable nature of the hybrid nanocomposites.

Sustainable synthesis and remarkable adsorption capacity of MOF/graphene oxide and MOF/CNT based hybrid nanocomposites for the removal of Bisphenol A from water.

A series of novel absorbents based on Cu-BDC MOFs decorated over graphene oxide (GrO) and carbon nanotubes (CNTs) hybrid nanocomposites, namely Cu-BDC@GrO and Cu-BDC@CNT, are synthesized via a facile and one-pot green solvothermal method for water remediation. The nanocomposites were characterized by XRD, TEM, SEM, EDS, Raman, FTIR, TGA, XPS, Zetasizer and ICP-OES instruments. XRD results confirmed the high crystalline structure of the synthesized hybrid nanocomposites. Morphological analysis by SEM and TEM verified the successful decoration of nano-sized Cu-BDC MOFs over GrO and CNT platforms; whereas, EDS and XPS analysis confirmed the presence of all components in the hybrid nanocomposites. Bisphenol A was used in this study as a model organic pollutant that is sometimes present in the industrial wastewater to test the adsorption capacity of the prepared hybrid nanomaterials toward their removal from water. The hybrid nanomaterials showed remarkable adsorption capacity of 182.2 and 164.1 mg/g toward the removal of BPA, which was several times higher than that of 60.2 mg/g for Cu-BDC MOF itself. The Langmuir, Freundlich, Temkin and D-R isotherm models were applied to analyze the experimental data and the results revealed that the Freundlich model describes the experimental data best. A kinetic study was carried out and it showed that the prepared nanomaterials could remove maximum amount of BPA from water in 30 min. The pseudo-first order, pseudo-second order and intra-particle diffusion models were applied to evaluate the kinetic data and the results suggested that the kinetics data could be well fitted to the pseudo-second order kinetic model. Additionally, the BAP adsorption process onto the hybrid nanocomposites was spontaneous and exothermic. The π-π interactions between the BPA and hybrid nanomaterials played a vital role during the BPA adsorption process. The higher adsorption capacity and water stability makes them a good candidate for water remediation applications.

Immobilization and microencapsulation of Lactobacillus caseii and Lactobacillus plantarum using zeolite base and evaluating their viability in gastroesophageal-intestine simulated condition / Inmovilización y microencapsulación de Lactobacillus caseii y Lactobacillus plantarum usando base de zeolita y evaluando su viabilidad en condiciones simuladas de gastroesofágico-intestino

Aims: In order to improve survival in gastrointestinal conditions, probiotic bacteria, i.e. we developed a new encapsulation method of probiotics based on zeolite and by calcium-alginate zeolite-starch as an effective method for safer delivery of probiotics. Material and Methods: Lactobacillus casei (ATCC 39392) and Lactobacillus plantarum (ATCC 29521) were used as probiotics. After microorganism’s immobilization on zeolite base, encapsulation was done by calcium-alginate zeolite-starch with the extrusion method. Afterwards, they were incubated in the simulated gastric and intestinal condition. Viability of these bacteria was calculated on the basis of time required to reduce the logarithmic base in the microbial population. SEM techniques were used to study the appearance of the capsules. Results: after incubation for 120 min under simulated gastric condition and 180 min in intestinal juice conditions (pH=8.2), the count of alive L. casei and L. plantarum cells were 6.3 log cfu/ml and 7.3 log cfu/ ml. However, for controlling the cells, this value was zero and 2.1 log cfu/ml respectively. Conclusion: According to the results, we had an increase of the survival rate of L. casei and L. plantarum in gastroesophageal-intestine simulated condition. These results indicated good efficacy and high performance of zeolite for immobilization and microencapsulation of probiotics

Objetivos: Para mejorar la supervivencia en condiciones gastrointestinales de las bacterias probióticas, hemos desarrollado un nuevo método de encapsulación de probióticos a base de zeolita y almidón de zeolita de alginato de calcio como método eficaz para la administración más segura de probióticos. Material y métodos: se utilizaron Lactobacillus casei (ATCC 39392) y Lactobacillus plantarum (ATCC 29521) como probióticos. Después de la inmovilización del microorganismo en la base de zeolita, la encapsulación se realizó mediante zeolita-almidón de alginato de calcio con el método de extrusión. Posteriormente, se incubaron en la condición gástrica e intestinal simulada. La viabilidad de estas bacterias se calculó sobre la base del tiempo requerido para reducir la base logarítmica en la población microbiana. Las técnicas SEM se usaron para estudiar la apariencia de las cápsulas. Resultados: después de la incubación durante 120 minutos bajo condición gástrica simulada y 180 minutos en condiciones de jugo intestinal (pH = 8,2), el recuento de células vivas de L. casei y L. plantarum fue de 6,3 log ufc / ml y de 7,3 log ufc / ml. Sin embargo, para controlar las células, este valor era cero y 2,1 log cfu / ml respectivamente

Lactobacillus plantarum as a Probiotic Potential from Kouzeh Cheese (Traditional Iranian Cheese) and Its Antimicrobial Activity.

The aim of this study is to isolate and identify Lactobacillus plantarum isolates from traditional cheese, Kouzeh, and evaluate their antimicrobial activity against some food pathogens. In total, 56 lactic acid bacteria were isolated by morphological and biochemical methods, 12 of which were identified as Lactobacillus plantarum by biochemical method and 11 were confirmed by molecular method. For analyzing the antimicrobial activity of these isolates properly, diffusion method was performed. The isolates were identified by 318 bp band dedicated for L. plantarum. The isolated L. plantarum represented an inhibitory activity against four of the pathogenic bacteria and showed different inhibition halos against each other. The larger halos were observed against Staphylococcus aureus and Staphylococcus epidermidis (15 ± 0.3 and 14.8 ± 0.7 mm, respectively). The inhibition halo of Escherichia coli was smaller than that of other pathogen and some L. plantarum did not show any inhibitory activity against E. coli, which were resistant to antimicrobial compounds produced by L. plantarum. The isolated L. plantarum isolates with the antimicrobial activity in this study had strong probiotic properties. These results indicated the nutritional value of Kouzeh cheese and usage of the isolated isolates as probiotic strains.

Novel nanofiberous membrane fabricated via electrospinning of wastage fuzzes of mechanized carpet used for dye removal of the carpet dyeing wastewater.

Novel nanofibrous membrane was fabricated by using electrospinning of wastage fuzzes of mechanized carpet which was used to remove the dye of the textile wastewater. SEM images showed that nanofibers with average diameters of 200 nm were successfully fabricated by electrospinning technique. The physicochemical properties of electrospun nanofiberous membranes were studied by differential scanning calorimetry (DSC), energy-dispersive X-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. FTIR confirmed the presence of C≡N, C=N, and C‒N groups in the electrospun nanofibers which are the main functional groups of polyacrilonitrile (PAN). The resulting membrane showed dye retention of 96% of carpet dyeing wastewater, demonstrating the high separation potential of such membrane for wastewater treatment. We believe that simple approaches such as the present one would open up enormous possibilities in effective uses of wastage fuzzes of textile industry, considering the fact that electrospinning is a cost-effective method for the mass scale production of nanofibers.