Self-assembled Sodium Research Articles

Self-assembled sodium alginate/graphene hydrogel enhances sulfamethoxazole removal: Impacts of hydrogel properties on the microbial community

Sulfamethoxazole (SMX), a common antibiotic, is frequently present in various wastewater sources and threatens ecological health. Biodegradation technology is a sustainable method for removing antibiotics in which biological graphene hydrogel (BGH) has an advantage in SMX removal. However, there is limited understanding of the environmentally friendly method for the formation of bio-graphene complexes and their mechanism in SMX removal. This research is focused on investigating and evaluating the performance of BGH cross-linked with sodium alginate in removing SMX, as well as the mechanisms involved in the removal process. The outcomes showed that the biocompatibility of alginate-BGH (A-BGH) allows for an increase in SMX removal, reaching up to 91.23 %. This improved SMX removal can be attributed to the fuller 3D porous structure and fewer oxygen-containing functional groups of A-BGH, which maintained the microbial community diversity. Therefore, microorganisms involved in SMX degradation, like Pseudomonas, Desulfomicrobium, and Desulfovibrio, maintained a comparable high abundance in A-BGH. This microbial community contributes to three major transformation pathways, including hydroxylation, NC bond cleavage, and N–S bond cleavage, thereby enhancing the SMX removal. The present finding demonstrated the effective adsorption and biodegradation behavior of A-BGH on SMX, indicating the A-BGH may serve as a promising material for aquatic environment remediation and wastewater treatment.

Self-assembled sodium alginate polymannuronate nanoparticles for synergistic treatment of ophthalmic infection and inflammation: Preparation optimization and in vitro/vivo evaluation

Frequent administrations are often needed during the treatment of ocular diseases due to the low bioavailability of the existing eye drops owing to inadequate corneal penetration and rapid drug washout. Herein, sodium alginate polymannuronate (SA) nanocarriers were developed using ionic gelation method that can provide better bioavailability through mucoadhesivity and sustained drug release by binding to the ocular mucus layer. This study disproves the common belief that only the G block of SA participates in the crosslinking reaction during ionic gelation. Self-assembly capability due to the linear flexible structure of the M block, better biocompatibility than G block along with the feasibility of controlling physicochemical characteristics postulate a high potential for designing efficient ocular drug delivery systems. Initially, four crosslinkers of varied concentrations were investigated. Taguchi design of experiment revealed the statistically significant effect of the crosslinker type and concentration on the particle size and stability. The best combination was detected by analyzing the particle size and zeta potential values that showed the desired microstructural properties for ocular barrier penetration. The desired combination was SA-Ca-1 that had particle size within the optimal corneal penetration range, that is 10-200 nm (135 nm). The drug carriers demonstrated excellent entrapment efficiency (∼89 % for Ciprofloxacin and ∼96 % for Dexamethasone) along with a sustained and simultaneous release of dual drug for at least 2 days. The nanoparticles also showed biocompatibility (4 ± 0.6 % hemolysis) and high mucoadhesivity (73 ± 2 % for 0.25 g) which was validated by molecular docking analysis. The prepared formulation was able to reduce the scleral inflammation of the rabbit uveitis models significantly within 3 days. Thus, the eye drop showed remarkable potential for efficient drug delivery leading to faster recovery.

Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by Temperature

Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by Temperature

Highly water permeable ‘reverse osmosis’ polyamide membrane of folded nanoscale film morphology

Desalination membrane is playing a major role to meet the need of clean water for human, agricultural and industrial uses. Engineering of the membrane structure for enhancement of water permeability while maintaining salt rejection efficiency would bring benefits of high throughput product water and quality. We explored fabrication of ‘reverse osmosis’ desalination membrane by use of self-assembled sodium dodecyl sulphate surfactant micelle as structure directing agent in ordering reactive monomers towards an organized network leading to thin-film membrane deposition over the nodular structure of polysulfone porous substrate of 50–100 nm. Using small-angle neutron scattering, we studied the change of nanoscale self-assemblies of micellar structure depending on the surfactant concentration, which influenced on the formation of the membranes of improved performance. We found that the larger micellar structure (ellipsoidal) assisted fabrication gave the membrane with the best improvement in the desalination performance in terms of water flux increment by ∼180 % and further pore size refinement with increment in salt-rejection selectivity by ∼5 %.

Experimental and computational insights into self-assembly sodium oleate on anodized aluminum interface in electric field

Electrochemical etching method has been used to construct anode aluminum foils with large surface area for electrolytic capacitor application. The applied current concentrated on surface defects would cause excessive corrosion of aluminum substrate and accelerate the initiation of merged tunnels. Self-assembly treatment with sodium oleate presents considerable improvement on optimization of size and structure of etched tunnels. Experimentally, aluminum foils with high etched tunnel density nearly 1.5027 × 107 cm−2 could be prepared after 0.10 mmol L−1 sodium oleate treatment. Theoretically, molecular dynamic and quantum chemistry calculations reveal the self-assembly process of sodium oleate in forms of oleic acid on Al (100) facet. The results indicate that the oleic acid monolayer will form at molecular density nearly 0.855, 0.847 and 0.844 mol. nm−2 as electric field E equal 0, 0.10 V Å−1 and 1.00 V Å−1, respectively. Based on the calculations of surface coverage in electric field conditions, experimental adsorption isotherm has been corrected to determine the optimal concentration of self-assembly composition.

Facile design of a stable and inorganic underwater superoleophobic copper mesh modified by self-assembly sodium silicate and aluminum oxide for oil/water separation with high flux

Separation meshes with special wettability for oil/water separation have drawn much research attention and the preparation of superhydrophobic or underwater superoleophobic materials for oil/water separation has been extensively studied. However, the preparation procedures of inorganic coatings in previous studies were complex and the widely used organic compounds for surface modification were costly and unstable. To address these challenges, the layer-by-layer self-assembly process of inorganic sodium silicate and aluminum oxide powders (SSA) on the copper (Cu) mesh was explored in this paper. Hierarchical and rough structures after electrodepostion were observed by scanning electron microscope (SEM). On the SSA modified Cu mesh, contact angles (CA) of underwater trichloromethane and water in the air were 153° and 1°, respectively. Besides, the modified mesh exhibited high thermal stability, good oil/water separation properties with water flux of 19832 Lm−2h−1 and separation efficiency > 95%, and high recycling performance. The oil/water separation mechanism was that the positive intrusion pressure and the repulsive force for oil contributed to the oil/water separation performance of the mesh. The obtained mesh featured in facile design, unique wettability (underwater superoleophobic), high flux, and good recyclability and thermal stability. Therefore, it is believed that the self-assembly strategy proposed in this paper may provide a reference for preparing a highly stable inorganic mesh for oil/water separation.

Optimization and Formulation of Nanostructured and Self-Assembled Caseinate Micelles for Enhanced Cytotoxic Effects of Paclitaxel on Breast Cancer Cells.

Background: Paclitaxel (PTX) is a widely used anti-cancer drug for treating various types of solid malignant tumors including breast, ovarian and lung cancers. However, PTX has a low therapeutic response and is linked with acquired resistance, as well as a high incidence of adverse events, such as allergic reactions, neurotoxicity and myelosuppression. The situation is compounded when its complex chemical structure contributes towards hydrophobicity, shortening its circulation time in blood, causing off-target effects and limiting its therapeutic activity against cancer cells. Formulating a smart nano-carrier may overcome the solubility and toxicity issues of the drug and enable its more selective delivery to the cancerous cells. Among the nano-carriers, natural polymers are of great importance due to their excellent biodegradability, non-toxicity and good accessibility. The aim of the present research is to develop self-assembled sodium caseinate nanomicelles (NaCNs) with PTX loaded into the hydrophobic core of NaCNs for effective uptake of the drug in cancer cells and its subsequent intracellular release. Methods: The PTX-loaded micelle was characterized with high-performance liquid chromatography (HPLC), Fourier Transform Infrared Spectra (FTIR), High Resolution-Transmission Electron Microscope (HR-TEM), Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray (EDX). Following treatment with PTX-loaded NaCNs, cell viability, cellular uptake and morphological changes were analyzed using MCF-7 and MDA-MB 231 human breast cancer cell lines. Results: We found that PTX-loaded NaCNs efficiently released PTX in an acidic tumor environment, while showing an enhanced cytotoxicity, cellular uptake and in-vivo anti-tumor efficacy in a mouse model of breast cancer when compared to free drug and blank micelles. Additionally, the nanomicelles also presented improved colloidal stability for three months at 4 °C and −20 °C and when placed at a temperature of 37 °C. Conclusions: We conclude that the newly developed NaCNs is a promising carrier of PTX to enhance tumor accumulation of the drug while addressing its toxicity issues as well.

PH-Dependent Chiral Recognition of D- and L-Arginine Derived Polyamidoamino Acids by Self-assembled Sodium Deoxycholate.

D- and L-arginine-based polyamidoamino acids, called D- and L-ARGO7, retain the chirality and acid/base properties of the parent α-amino acids and show pH-dependent self-structuring in water. The ability of the ARGO7 chiral isomers to selectively interact with chiral biomolecules and/or surfaces was studied by choosing sodium deoxycholate (NaDC) as a model chiral biomolecule for its ability to self-assembly into globular micelles, showing enantio-selectivity. To this purpose, mixtures of NaDC with D-, L- or D,L-ARGO7, respectively, in water were analysed by circular dichroism (CD) spectroscopy and small-angle neutron scattering (SANS) at different levels of acidity expressed in terms of pD and concentrations. Differences in the CD spectra indicated chiral discrimination for NaDC/ARGO7 mixtures in the gel phase (pD 7.30) but not in the solution phase (pD 9.06). SANS measurements confirmed large scale structural perturbation induced by this chiral discrimination in the gel phase yet no modulation of the structure in the solution phase. Together, these techniques shed light on the mechanism by which ARGO7 stereoisomers modify the morphology of NaDC micelles as a function of pH. This work demonstrates chirality-dependent interactions that drive structural evolution and phase behaviour of NaDC, opening the way for designing novel smart drug delivery systems.

Enhanced Treatment Effects of Tilmicosin Against Staphylococcus aureus Cow Mastitis by Self-Assembly Sodium Alginate-Chitosan Nanogel.

The Staphylococcus aureus (S. aureus) cow mastitis causes great losses to the cow industry. In order to improve the treatment effect of tilmicosin against cow mastitis, the combination of solid lipid nanoparticle (SLN) technology with in situ hydrogel technology was used to prepare the self-assembly tilmicosin nanogel (TIL-nanogel). The physicochemical characteristics, in vitro release, antibacterial activity and in vivo treatment efficacy of TIL-SLNs and TIL-nanogel were studied, respectively. The results showed the loading capacity (LC), encapsulation efficiency (EE), size, zeta potential and poly dispersion index (PDI) of TIL-nanogel were 23.33 ± 0.77%, 67.89 ± 3.01%, 431.57 ± 12.87 nm, 8.3 ± 0.06 mv and, 0.424 ± 0.032, respectively. The TIL-nanogel showed stronger sustained release in vitro than TIL-SLNs and commercial injection. The cure rate of half dosage and normal dosage of TIL-nanogel was 58.3% and 75.0%, which was higher than that of commercial injection (50.0%) at normal dosage. The results suggest that the treatment dosage of tilmicosin for cow mastitis could be reduced by TIL-nanogel. The novel TIL-nanogel will be beneficial by decreasing the usage of tilmicosin and the treatment costs of cow mastitis.

Assessment of synergistic interactions on self-assembled sodium alginate/nano-hydroxyapatite composites: to the conception of new bone tissue dressings

The aim of this work is to assess the behavior of biocomposites (CPSs) in regard to the generation of biogenic hydroxyapatite and also their degradation depending on the concentration of cross-linker agent, pH, and ionic strength. The development of these composites with potential application in bone tissue regeneration is based on alginate and synthetic nano-hydroxyapatite (nano-HA), which was used as a cross-linker agent. The CPSs showed the capability to develop biogenic hydroxyapatite when they were incubated in simulated body fluid (SBF) depending on the incubation time and concentration of the linker. These results were analyzed by x-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Furthermore, the CPSs have shown resistance to the degradation (demonstrated by swelling and dissolution tests) when the mentioned conditions were modified. Finally, the development of a liquid crystalline phase within the composites, which contributes to reinforce their structure, is a novel finding in this study. This behavior has been shown by means of optical microscopy (OM) with crossed polaroids. Thus, these composites displayed promising results to be used as bone filling materials in the future.

Preparation of Nanowire Silica Inside Self-Assembled Sodium Bis(2-ethylhexyl) Sulfosuccinate (AOT) Gels.

In conventional sol-gel methods, gel formation occurs due to aggregation of particles into irregular shapes of larger size. In this study, we conducted hydrolysis-condensation reactions of tetraethyl orthosilicate (TEOS) within water-laden channels inside the space created by self-assembled AOT molecules to prepare regular and nanosized silica in self-assembled sodium bis(2-ethylhexyl) sulfosuccinate (AOT) gels. The AOT gels were obtained by adding small amounts of water to organic solvents containing high concentrations of AOT. Adding silica significantly influenced the rheological properties and microstructures of these AOT/silica gels. Rheological studies showed that the storage modulus G' and loss modulus G″ of the AOT gel systems became very close and even crossed, indicating that the gel is "weak"; however, for the AOT/silica gel systems, the rheological data demonstrated that G' is greater than G″ at all frequencies, indicative of a real gel with a G' of approximately 10(5) pa. Small-angle X-ray scattering (SAXS) results showed that the gels initially had a hexagonal close-packed cylindrical structure with long-range order and transitioned to nonclose-packed cylindrical structures without long-range order as the silica formed. The cylinder is expected to comprise stacks of silica molecules surrounded by AOT molecules, and the radius of the cylinder is close to the sum of the length of one AOT molecule and half the size of one silica molecule. The rheological and SAXS data show that silica in the AOT/silica systems grew in the axial direction due to the confinement of these cylindrical structures, leading to nanowire silica structures. After removal of the AOT components, the nanowire silica was approximately 5-10 nm in diameter, as observed using transmission electron microscopy (TEM).

Preparation and characterization of highly water-soluble magnetic Fe3O4 nanoparticles via surface double-layered self-assembly method of sodium alpha-olefin sulfonate

A kind of double-layered self-assembly sodium alpha-olefin sulfonate (AOS) capped Fe3O4 magnetic nanoparticles (Fe3O4-AOS-MN) with highly water-solubility was prepared by a wet co-precipitation method with a pH of 4.8. The resulting Fe3O4-AOS-MN could be dispersed into water to form stable magnetic fluid without other treatments. The result of X-ray diffraction (XRD) indicated that the Fe3O4-AOS-MN maintained original crystalline structure and exhibited a diameter of about 7.5nm. The iron oxide phase of nanoparticles determined by Raman spectroscopy is Fe3O4. Transmission electron microscopy (TEM) analysis confirmed that the Fe3O4-AOS-MN with spherical morphology were uniformly dispersed in water. FT-IR spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) verified the successful preparation of Fe3O4-AOS-MN capped with double-layered self-assembled AOS. The corresponding capacities of monolayer chemical absorption and the second-layer self-assembly absorption were respectively 4.07 and 14.71wt% of Fe3O4-MN, which were much lower than those of other surfactants. Vibrating sample magnetometer (VSM) test result showed Fe3O4-AOS-MN possessed superparamagnetic behavior with the saturation magnetization value of about 44.45emu/g. The blocking temperature TB of Fe3O4-AOS-MN capped with double-layered AOS is 170K.

New Phases Found in Reverse Micelle Systems with High Concentrations of AOT

This paper discusses the phase behavior, rheology, and structure of self-assembled sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelle systems at high AOT concentrations. When the amount of AOT and w(o) (the molar ratio of water to AOT) were changed, many different phases were found, a fact which is not discussed in the literature. Opaque gel-like phase (phase separation) occurred with high concentrations of AOT in organic solvents without water. When the AOT concentration and w(o) were increased to 18-72 m and 2, respectively, the samples were gel-like and translucent. Dynamic rheological results indicate that the viscoelastic transition agreed with a multirelaxation time model. Small-angle X-ray scattering (SAXS) results imply that these samples showed a hexagonally close-packed cylindrical structure in which the diameter of a cylinder was ~2.5-3.0 nm, depending on the water contents. Moreover, these AOT cylinders self-assembled into fiber bundles with a diameter of 1-10 μm, as determined using a polarized optical microscope. As w(o) was increased to 2-6 in 72 m AOT samples, similar rheological and SAXS results were obtained. However, a different type of viscoelastic transition occurred, from multirelaxation to single-relaxation, when w(o) was increased to 7-11. The samples were in the transparent gel-like phase, and the structures determined by SAXS were a combination of hexagonally packed cylindrical and lamellar structure. The close-packed cylindrical structures had larger radii and shorter lengths with increasing w(o). Furthermore, when w(o) was increased to 12, the gel-like phase disappeared and a highly viscous solution was observed. This is because all the cylindrical structures collapsed and transformed into lamellar structures when the amount of water was further increased.

NANOSIZE STRUCTURE OF SELF-ASSEMBLY SODIUM DODECYL SULFATE: A STUDY BY SMALL ANGLE NEUTRON SCATTERING (SANS)

Small Angle Neutron Scattering (SANS) investigation on the self-assembly sodium dodecyl sulfate (SDS) molecules as a function of concentration and additives has been carried out. SANS spectrometer which has been completely installed at the neutron scattering laboratory (NSL) BATAN in Serpong, Indonesia has played most important role to determine the growth (size) and also the shapes of a micelle structure. In this works we report that spherical micelle structure with a radius of 16.7 Å will transform to ellipsoidal or rod-like micelle structure with the long axis extends up to 50 Å by increasing the concentration of SDS. Similar to that the micelle structures change by addition of salt in SDS micellar solutions. Keywords: nanostructure, micelle, self-assembly

Control of uniform nanostructured α-Ni(OH) 2 with self-assembly sodium dodecyl sulfate templates

Morphological control of the nanostructured α-Ni(OH) 2 is achievable via self-assembly of sodium dodecyl sulfate (SDS) as templates accompanied with microwave-assisted homogeneous alkalization process. The synthesized α-Ni(OH) 2 can be 2-D hexagonal nano-sheets, macroporous micro-spheres or irregular-shaped platelets, depending on the SDS concentration. Further, the interlayer spacing of the synthesized α-Ni(OH) 2 crystalline was determined to be 2.47 nm, indicating the intercalation of DS − anions between brucite layers. The results explain the morphological change of the synthesized α-Ni(OH) 2 with SDS concentration, which provides a way to morphological control of metal hydroxides. The corresponding electrochemical properties for the α-Ni(OH) 2 synthesized with and without SDS are characterized as well, showing the advantages of the 2-D hexagonal nano-sheets.

Atomic Force Microscopy Study of Self-Assembled Sodium Chloride Nanocrystallites and Their Morphology Transitions

Identically oriented NaCl nanocrystallites have been grown on mica surfaces based on a facile solution-evaporated method. With an increase in humidity, the morphology of the NaCl nanocrystallites evolves in succession from triangular pyramids to cubic islands and then to long lines with lengths of up to millimeters. These nanocrystallites can self-assemble into highly ordered arrays with large spatial extents of ∼10 mm2 under high humidity conditions when the value of relative humidity is higher than 40%. Their morphology transitions and self-assemblies can be understood in terms of controlled epitaxial crystallization together with water adsorption at the surface of the growing nanocrystallites.

Rodlike silica and titania objects templated on extremely dilute aqueous dispersions of self-assembled sodium lithocholate nanotubes

Simple methods for preparation of mesoporous rodlike silica and titania nanoobjects, some with exceedingly high aspect ratios, are described. They involve hydrolytic sol–gel processes using nanotubes from aqueous assemblies of very dilute (0.1 wt%) sodium lithocholate as templates. Shearing of the lithocholate nanotubes results in aligned, templated silica rods. The relative rates of lithocholate self-assembly and of polymerization of the titania precursors, especially, appear to be important factors in templating efficiency.