Effect of interparticle interactions on size determination of zirconia and silica based systems – A comparison of SAXS, DLS, BET, XRD and TEM

Delivery of beclomethasone dipropionate nanosuspensions with an electronic cigarette

The aim of this work was to ascertain the ability of electronic nicotine delivery systems (ENDS) to deliver drug nanocrystals through the produced aerosol. A nanocrystal nanosuspension of beclomethasone dipropionate, a synthetic chlorinated corticosteroid diester commonly used by inhalation in the treatment of asthma and chronic obstructive pulmonary disease, was prepared with a wet media milling technique using Poloxamer 188 as stabilizer. The obtained nanosuspension was thoroughly characterized by different techniques: transmission electron microscopy, photon correlation spectroscopy, X-ray powder diffractometry and Fourier transform infrared spectroscopy. The nanosuspension was then loaded in the cartomizer of the electronic cigarette and the produced aerosol was collected and analysed, confirming the presence of drug nanocrystals. The results of this study suggested the possible alternative use of ENDS as medical device for the delivery of poorly soluble drugs.

Epoxy Resin Nanocomposites: The Influence of Interface Modification on the Dispersion Structure—A Small-Angle-X-ray-Scattering Study

The surface functionalization of inorganic nanoparticles is an important tool for the production of homogeneous nanocomposites. The chemical adaptation of the nano-filler surface can lead to effective weak to strong interactions between the fillers and the organic matrix. Here we present a detailed systematic study of different surface-functionalized particles in combination with a SAXS method for the systematic investigation of the interface interaction in the development of epoxy nanocomposites. We investigated the effect of surface modification of spherical SiO2 nanoparticles with 9 nm and 72 nm diameter and crystalline ZrO2 nanoparticles with 22 nm diameter on the homogeneous distribution of the fillers in diethylenetriamine (DETA) cured bisphenol-F-diglycidylether epoxy resin nanocomposites. Unmodified nanoparticles were compared with surface-modified oxides having diethylene glycol monomethyl ethers (DEG), 1,2-diols, or epoxy groups attached to the surface. The influence of surface modification on dispersion quality was investigated by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) for inorganic filler contents of 3, 5 and 10 wt%. It was shown that the dispersion quality can be optimized by varying the coupling agent end group to obtain homogeneous and transparent nanomaterials. UV/VIS measurements confirmed the transparency/translucency of the obtained materials. The relationship between particle–matrix interaction and particle–particle interaction plays a decisive role in homogeneity and is controlled by the surface groups as well as by the type, size, and morphology of the nanoparticles themselves.

Effect of Zirconium oxide nanoparticle on serum level of testosterone and spermatogenesis in the rat: An experimental study

BACKGROUND

Zirconium nanoparticles are used as health agents, pharmaceutical carriers, and in dental and orthopedic implants.

OBJECTIVE

This studyaimed to investigate the effects of Zirconium oxide nanoparticles on the process of spermatogenesis in rat.

MATERIALS AND METHODS

In this experimental study, 32 male Wistar rats (150-200 gr), with range of age 2.5 to 3 months were used and divided into four groups of eight per each. The control group received 0.5 ml of distilled water and the three experimental groups received 50, 200, and 400 ppm doses of Zirconium oxide nanoparticles solution over a 30-day period, respectively. At the end of the experiment, tissue sections were taken from the testis and stained with hematoxylin-eosin. Serum concentration of testosterone was measured by enzyme-linked immunosorbent assay.

RESULTS

In the experimental group receiving 400 ppm Zirconium oxide nanoparticles, the number of Spermatogonia cells (p ≤ 0.01), Spermatocytes (p ≤ 0.01), Spermatids (p ≤ 0.001), and sertoli and Leydig cells (p ≤ 0.05) showed a significant decrease compared to the control group. Serum testosterone concentration did not change significantly in all experimental groups receiving Zirconium oxide nanoparticles compared to the control group. Experimental group received 400 ppm Zirconium oxide nanoparticles shrinkage of seminal tubules and reduced lumen space compared to control group.

CONCLUSION

Zirconium oxide nanoparticles are likely to damage the testes by increasing Reactive oxygen species production and free radicals.

An effective approach for size characterization and mass quantification of silica nanoparticles in coffee creamer by AF4-ICP-MS

Silicon dioxide (SiO₂) has been used as a food additive (E551) for decades. However, some safety concerns have been raised recently due to the detection of silica nanoparticles (SiO₂ NPs) in a variety of foodstuffs and their unknown long-term health risk to humans. In order for risk assessment to be conducted, it is essential to establish a reliable, valid, and pragmatic method for analysis of SiO₂ NPs in foods for estimation of exposure. This paper presents an effective approach for both size characterization and mass quantification of SiO₂ NPs in commercial high-fat coffee creamer using asymmetric flow field-flow fractionation (AF4) coupled to inductively coupled plasma mass spectrometry (ICP-MS). SiO₂ NPs from coffee creamer were well extracted after cleanup with hexane in a two-phase (hexane vs. water) aqueous environment. Size determination of SiO₂ NPs was performed by on-line AF4-ICP-MS based on calibration with monodispersed standards. The dominant primary size of SiO₂ NPs in the studied sample was 36.5 nm. The mass percentages of SiO₂ NPs (vs. total SiO₂) were 18.6% for the dominant primary nano-silica particles by prechannel calibration and 35.7% for total SiO₂ NPs (≤ 100 nm) by postchannel calibration, with recoveries of 89-96% for the former and 75% for the latter. The established approach was demonstrated to be efficient and practical for routine analysis of polydispersed SiO₂ NPs with wide nano-size distribution in coffee creamer. This method may be extended to monitor the presence of SiO₂ NPs in other similar complex food matrices. Graphical abstract.

A Micelle Electrolyte Enabled by Fluorinated Ether Additives for Polysulfide Suppression and Li Metal Stabilization in Li-S Battery

The Li-S battery is a promising next-generation technology due to its high theoretical energy density (2600 Wh kg⁻¹) and low active material cost. However, poor cycling stability and coulombic efficiency caused by polysulfide dissolution have proven to be major obstacles for a practical Li-S battery implementation. In this work, we develop a novel strategy to suppress polysulfide dissolution using hydrofluoroethers (HFEs) with bi-functional, amphiphlic surfactant-like design: a polar lithiophilic “head” attached to a fluorinated lithiophobic “tail.” A unique solvation mechanism is proposed for these solvents whereby dissociated lithium ions are readily coordinated with lithiophilic “head” to induce self-assembly into micelle-like complex structures. Complex formation is verified experimentally by changing the additive structure and concentration using small angle X-ray scattering (SAXS). These HFE-based electrolytes are found to prevent polysulfide dissolution and to have excellent chemical compatibility with lithium metal: Li||Cu stripping/plating tests reveal high coulombic efficiency (>99.5%), modest polarization, and smooth surface morphology of the uniformly deposited lithium. Li-S cells are demonstrated with 1395 mAh g⁻¹ initial capacity and 71.9% retention over 100 cycles at >99.5% efficiency—evidence that the micelle structure of the amphiphilic additives in HFEs can prohibit polysulfide dissolution while enabling facile Li⁺ transport and anode passivation.

Nanoscale perfluorocarbon expediates bone fracture healing through selectively activating osteoblastic differentiation and functions

BACKGROUND AND RATIONALE

Fracture incidence increases with ageing and other contingencies. However, the strategy of accelerating fracture repair in clinical therapeutics remain a huge challenge due to its complexity and a long-lasting period. The emergence of nano-based drug delivery systems provides a highly efficient, targeted and controllable drug release at the diseased site. Thus far, fairly limited studies have been carried out using nanomedicines for the bone repair applications. Perfluorocarbon (PFC), FDA-approved clinical drug, is received increasing attention in nanomedicine due to its favorable chemical and biologic inertness, great biocompatibility, high oxygen affinity and serum-resistant capability. In the premise, the purpose of the current study is to prepare nano-sized PFC materials and to evaluate their advisable effects on promoting bone fracture repair.

RESULTS

Our data unveiled that nano-PFC significantly enhanced the fracture repair in the rabbit model with radial fractures, as evidenced by increased soft callus formation, collagen synthesis and accumulation of beneficial cytokines (e.g., vascular endothelial growth factor (VEGF), matrix metalloprotein 9 (MMP-9) and osteocalcin). Mechanistic studies unraveled that nano-PFC functioned to target osteoblasts by stimulating their differentiation and activities in bone formation, leading to accelerated bone remodeling in the fractured zones. Otherwise, osteoclasts were not affected upon nano-PFC treatment, ruling out the potential target of nano-PFC on osteoclasts and their progenitors.

CONCLUSIONS

These results suggest that nano-PFC provides a potential perspective for selectively targeting osteoblast cell and facilitating callus generation. This study opens up a new avenue for nano-PFC as a promising agent in therapeutics to shorten healing time in treating bone fracture.

Enhanced Photogenerated Electron Transfer in a Semiartificial Photosynthesis System Based on Highly Dispersed Titanium Oxide Nanoparticles

In this study, a hybrid semiartificial photosynthesis system based on chloroplast (CLP) and titanium oxide nanoparticles (TiO₂ NPs) was constructed. 2,6-Dichlorophenolindophenol (DCPIP) reduction by TiO₂/CLP complex and methylene blue (MB) reduction by TiO₂ were used to determine enhanced photogenerated electron transfer in this hybrid system. The DCPIP reduction by the TiO₂/CLP complex showed the same trend as MB reduction by TiO₂ as a function of concentration of TiO₂ NPs, indicating interception of photogenerated electrons in TiO₂ by CLP that leads to enhanced photosynthesis efficiency. Decreased photoluminescence intensity and shortened excited-state lifetime of the TiO₂/CLP complex compared to that of pure TiO₂ also support electron transfer from TiO₂ to CLP. Longer visible light absorption wavelength and increasing valence band edges reveal the narrower band gap of TiO₂/CLP, which finally results in the enhanced electron transfer from TiO₂ to CLP. Higher ferricyanide reduction and enhanced ATP formation with the TiO₂/CLP complex demonstrate the accelerated electron-transfer rate of the electron-transfer chain. This study reveals the mechanism of how TiO₂ interacts with CLP to enhance the photosynthesis via constructing a semiartificial photosynthesis system.

Dual-peptide functionalized acetalated dextran-based nanoparticles for sequential targeting of macrophages during myocardial infarction

The advent of nanomedicine has recently started to innovate the treatment of cardiovascular diseases, in particular myocardial infarction. Although current approaches are very promising, there is still an urgent need for advanced targeting strategies. In this work, the exploitation of macrophage recruitment is proposed as a novel and synergistic approach to improve the addressability of the infarcted myocardium achieved by current peptide-based heart targeting strategies. For this purpose, an acetalated dextran-based nanosystem is designed and successfully functionalized with two different peptides, atrial natriuretic peptide (ANP) and linTT1, which target, respectively, cardiac cells and macrophages associated with atherosclerotic plaques. The biocompatibility of the nanocarrier is screened on both macrophage cell lines and primary macrophages, showing high safety, in particular after functionalization of the nanoparticles' surface. Furthermore, the system shows higher association versus uptake ratio towards M2-like macrophages (approximately 2-fold and 6-fold increase in murine and human primary M2-like macrophages, respectively, compared to M1-like). Overall, the results demonstrate that the nanosystem has potential to exploit the "hitchhike" effect on M2-like macrophages and potentially improve, in a dual targeting strategy, the ability of the ANP peptide to target infarcted heart.

Recent Advances in Water Treatment Using Graphene-based Materials

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A variety of processes were reported for efficient removing of heavy metal from wastewater, including but not limited to ion exchange, reverse osmosis, membrane filtration, flotation, coagulation, chemical precipitation, solvent extraction, electrochemical treatments, evaporation, oxidation, adsorption, and biosorption. Among the aforementioned techniques, adsorption/ion exchange has been known as a most important method for removing heavy metal ions and organic pollutants due to great removal performance, simple and easy process, cost-effectiveness and the considerable choice of adsorbent materials.

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Nanotechnology and its applications have been developed in most branches of science and technology. Extensive studies have been conducted to remove heavy metal ions from wastewater by preparation and applications of various nanomaterials. Nanomaterials offer advantages in comparison to other materials including an extremely high specific surface area, low-temperature modification, short intraparticle diffusion distance, numerous associated sorption sites, tunable surface chemistry, and pore size. In order to evaluate an adsorbent, two key parameters are: the adsorption capacity and the desorption property. The adsorption parameters including the absorbent loading, pH and temperature, concentration of heavy metal ion, ionic strength, and competition among metal ions are often studied and optimized.

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Several reviews have been published on the application of Graphene (G), Graphene Oxide (GO) in water treatment. In this minireview, we attempted to summarize the recent research advances in water treatment and remediation process by graphene-based materials and provide intensive knowledge of the removal of pollutants in batch and flow systems. Finally, future applicability perspectives are offered to encourage more interesting developments in this promising field. This minireview does not include patent literature.

Bilingual Peptide Nucleic Acids: Encoding the Languages of Nucleic Acids and Proteins in a Single Self-Assembling Biopolymer

Nucleic acids and proteins are the fundamental biopolymers that support all life on Earth. Nucleic acids store large amounts of information in nucleobase sequences while peptides and proteins utilize diverse amino acid functional groups to adopt complex structures and perform wide-ranging activities. Although nature has evolved machinery to read the nucleic acid code and translate it into amino acid code, the extant biopolymers are restricted to encoding amino acid or nucleotide sequences separately, limiting their potential applications in medicine and biotechnology. Here we describe the design, synthesis, and stimuli-responsive assembly behavior of a bilingual biopolymer that integrates both amino acid and nucleobase sequences into a single peptide nucleic acid (PNA) scaffold to enable tunable storage and retrieval of tertiary structural behavior and programmable molecular recognition capabilities. Incorporation of a defined sequence of amino acid side-chains along the PNA backbone yields amphiphiles having a "protein code" that directs self-assembly into micellar architectures in aqueous conditions. However, these amphiphiles also carry a "nucleotide code" such that subsequent introduction of a complementary RNA strand induces a sequence-specific disruption of assemblies through hybridization. Together, these properties establish bilingual PNA as a powerful biopolymer that combines two information systems to harness structural responsiveness and sequence recognition. The PNA scaffold and our synthetic system are highly generalizable, enabling fabrication of a wide array of user-defined peptide and nucleotide sequence combinations for diverse future biomedical and nanotechnology applications.

Understanding effect of solution chemistry on heteroaggregation of zinc oxide and copper oxide nanoparticles

The reported presence of mixture of nanoparticles in environmental water warrants developing understanding on their aggregation and fate. This study tried to address this question and focused on understanding effects of pH (3,7 and 10), background electrolyte concentration (1 mM and 10 mM as NaCl) and nanoparticle (NP) concentration (1 and 10 mg/L) on stability of suspension containing mixture of two commonly-found metal oxide-based NP (i.e., ZnO and CuO NPs) in a 6-h study (output variables: aggregation rate constant, settling rate constant, difference in zeta potential, change of metal content in suspension and on aggregates). Two iso-electric point values were obtained: pH 3.08 and 8.33 for mixture suspension in DI (De-ionized) water and pH 5.69 and 8.65 for mixture suspension with 10 mM electrolyte concentration. Settling rate constant and aggregation rate constant values of suspension containing mixture of NPs varied between 0.02 and 0.23 NTU/(NTU-hour) and 0.0002 and 0.03 nm/s, respectively. At natural pH condition, settling rate constant and aggregation rate constant values were obtained to be 0.05 NTU/(NTU- hour) and 0.012 nm/s. The Derjaguin-Landau-Verway-Overbeek (DLVO) analyses indicated that aggregation of mixture of NPs might be happening due to combined effects of ionic layer compression, charge neutralization and van der Waals attraction. Dissolution of nanoparticles was found to be significantly affected by change in pH of suspension. Stability of mixture of nanoparticles was observed to decrease with increasing pH, ionic strength and nanoparticle concentration values. For ZnO and CuO nanoparticles, model equations were developed for predicting their (i) aggregation rate constant, (ii) settling rate constant, (iii) difference in zeta potential, (iv) percentage change of metal in suspension and (v) solid Zn fractions of mixture of nanoparticles as a function of pH, ionic strength and NP concentration. These information are useful in understanding fate of mixture of NPs in suspension as well as in settled solids in natural water bodies and in water treatment systems.

Mesoporous bioactive glasses for the combined application of osteosarcoma treatment and bone regeneration

In this study, mesoporous bioactive glass (MBG) sub-micro particles were prepared through sol-gel synthesis and possessed a uniform and spherical structure with particle size of 302 ± 43 nm, a pore size of 4 nm and a high surface area of 354 m² g^-1. Alendronate (AL) is often used for the treatment of bone associated diseases, in particular osteosarcoma. However, due to the low bioavailability and high toxicity at increased doses, local and sustained release would be an ideal approach to AL delivery. Here, MBGs and aminated MBGs (AMBG) were applied as carriers for AL loading. High encapsulation efficiency of 75% and 85% and loading efficiency of 60% and 63%, for MBG and AMBG, respectively, was achieved. The release profile of AL from AMBG showed a better sustained and controlled release mechanism compared to MBG. In vitro results demonstrated the non-cytotoxic nature of both MBG and AMBG following exposure to MG63 osteoblast like cell line. AL release from MBG and AMBG, even at lower concentration, provoked decreased MG63 proliferation. The osteogenic potential of MBG and AMBG following exposure to dental pulp stem cells was evaluated using alizarin red assay.

Cycle Stability and Hydration Behavior of Magnesium Oxide and Its Dependence on the Precursor-Related Particle Morphology

Thermochemical energy storage is considered as an auspicious method for the recycling of medium-temperature waste heat. The reaction couple Mg(OH)₂⁻MgO is intensely investigated for this purpose, suffering so far from limited cycle stability. To overcome this issue, Mg(OH)₂, MgCO₃, and MgC₂O₄·2H₂O were compared as precursor materials for MgO production. Depending on the precursor, the particle morphology of the resulting MgO changes, resulting in different hydration behavior and cycle stability. Agglomeration of the material during cyclization was identified as main reason for the decreased reactivity. Immersion of the spent material in liquid H₂O decomposes the agglomerates restoring the initial reactivity of the material, thus serving as a regeneration step.

Antibacterial Activity of Fructose-Stabilized Silver Nanoparticles Produced by Direct Current Atmospheric Pressure Glow Discharge towards Quarantine Pests

Development of efficient plant protection methods against bacterial phytopathogens subjected to compulsory control procedures under international legislation is of the highest concern having in mind expensiveness of enforced quarantine measures and threat of the infection spread in disease-free regions. In this study, fructose-stabilized silver nanoparticles (FRU-AgNPs) were produced using direct current atmospheric pressure glow discharge (dc-APGD) generated between the surface of a flowing liquid anode (FLA) solution and a pin-type tungsten cathode in a continuous flow reaction-discharge system. Resultant spherical and stable in time FRU-AgNPs exhibited average sizes of 14.9 ± 7.9 nm and 15.7 ± 2.0 nm, as assessed by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. Energy dispersive X-ray spectroscopy (EDX) analysis revealed that the obtained nanomaterial was composed of Ag while selected area electron diffraction (SAED) indicated that FRU-AgNPs had the face-centered cubic crystalline structure. The fabricated FRU-AgNPs show antibacterial properties against Erwinia amylovora, Clavibacter michiganensis, Ralstonia solanacearum, Xanthomonas campestris pv. campestris and Dickeya solani strains with minimal inhibitory concentrations (MICs) of 1.64 to 13.1 mg L-1 and minimal bactericidal concentrations (MBCs) from 3.29 to 26.3 mg L-1. Application of FRU-AgNPs might increase the repertoire of available control procedures against most devastating phytopathogens and as a result successfully limit their agricultural impact.

Poly(meth)acrylate-PVDF core–shell particles from emulsion polymerization: preferential formation of the PVDF β crystal phase

PVDF-poly(methacrylate) core–shell particles prepared via emulsion polymerization preferentially show β phase PVDF crystallinity.

Non-Noble Metal Oxide Catalysts for Methane Catalytic Combustion: Sonochemical Synthesis and Characterisation

The aim of this study was to obtain nanocrystalline mixed metal-oxide–ZrO₂ catalysts via a sonochemically-induced preparation method. The effect of a stabiliser’s addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and µRaman. The sonochemical preparation method allowed us to manufacture the catalysts with uniformly dispersed metal-oxide nanoparticles at the support surface. The catalytic activity was tested in a methane combustion reaction. The activity of the catalysts prepared by the sonochemical method was higher than that of the reference catalysts prepared by the incipient wetness method without ultrasonic irradiation. The cobalt and chromium mixed zirconia catalysts revealed their high activities, which are comparable with those presented in the literature.

Essential oil-mediated glycerosomes increase transdermal paeoniflorin delivery: optimization, characterization, and evaluation in vitro and in vivo

In this study, a novel glycerosome carrier containing essential oils was prepared for topical administration of paeoniflorin (PF) to enhance its transdermal drug delivery and improve drug absorption in the synovium. The formulation of glycerosomes was optimized by a uniform design, and the final vehicle was composed of 5% (w/v) phospholipid, 0.6% (w/v) cholesterol, and 10% (v/v) glycerol, with 2% (v/v) Speranskia tuberculata essential oil (STO) as the transdermal enhancer. The in vitro transdermal flux of PF loaded in the STO-glycerosomes was 1.4-fold, 1.6-fold, and 1.7-fold higher than those of glycerosomes, liposomes, and tinctures, respectively. In vivo studies showed that the use of STO-glycerosomes was associated with a 3.1-fold greater accumulation of PF in the synovium than that of common glycerosomes. This finding was confirmed by in vivo imaging studies, which found that the fluorescence intensity of Cy5.5-loaded STO-glycerosomes in mice knee joints was 1.8-fold higher than that of the common glycerosomes 5 h after administration. The glycerosomes mediated by STO exhibited considerable skin permeability as well as improved drug absorption in the synovium, indicating that STO-glycerosomes may be a potential PF transdermal delivery vehicle for the treatment of rheumatoid arthritis caused by synovium lesions.

Poly (ethylene-co-vinyl alcohol)-based polymeric thermo-responsive nanocarriers for controlled delivery of epirubicin to hepatocellular carcinoma

In this study, poly(ethylene-co-vinyl alcohol) (EVOH) as a novel biocompatible polymeric scaffold was surface modified by succinylation to get EVOHS and further pegylated to improve structural properties using methoxypolyethylene glycol (5000 Da) succinate (PEGS) along with targeting with retinoic acid (RA) to get final modified active and passive targeted conjugate (PEGS-EVOHS-RA) to evaluate its ability in carrying and delivery of epirubicin to hepatocellular carcinoma cell lines in response to varying temperatures. In this regard, the PEGS-EVOHS-RA conjugate was prepared through the desired chemical reactions and its structure was confirmed using ¹H-NMR and FT-IR spectra. The micelles were prepared from PEGS-EVOHS-RA by dialysis method. The Particle size and zeta potential were measured, and entrapment efficacy along with in vitro release efficiency in different temperatures were also studied. The structural morphology of optimized nanomicelle was studied by transmission electron microscopy micrographs. The desired final micelles were evaluated for their toxicity using MTT assay on HepG2 human hepatocellular carcinoma cell lines at normal (37 °C) and elevated temperature (45 °C). The results revealed that, as the hydrophilicity of micelles increased, all characteristic properties improved. Then, these micelles can be considered as potentially effective thermo responsive delivery systems for targeted delivery of cytotoxic agents to hepatocellular carcinoma.

Insight to Nanoparticle Size Analysis-Novel and Convenient Image Analysis Method Versus Conventional Techniques

The aim of this paper is to introduce a new image analysis program "Nanoannotator" particularly developed for analyzing individual nanoparticles in transmission electron microscopy images. This paper describes the usefulness and efficiency of the program when analyzing nanoparticles, and at the same time, we compare it to more conventional nanoparticle analysis techniques. The techniques which we are concentrating here are transmission electron microscopy (TEM) linked with different image analysis methods and X-ray diffraction techniques. The developed program appeared as a good supplement to the field of particle analysis techniques, since the traditional image analysis programs suffer from the inability to separate the individual particles from agglomerates in the TEM images. The program is more efficient, and it offers more detailed morphological information of the particles than the manual technique. However, particle shapes that are very different from spherical proved to be problematic also for the novel program. When compared to X-ray techniques, the main advantage of the small-angle X-ray scattering (SAXS) method is the average data it provides from a very large amount of particles. However, the SAXS method does not provide any data about the shape or appearance of the sample.

Sub-CMC solubilization of dodecane by rhamnolipid in saturated porous media

Experiments were conducted with a two-dimensional flow cell to examine the effect of monorhamnolipid surfactant at sub-CMC concentrations on solubilization of dodecane in porous media under dynamic flow conditions. Quartz sand was used as the porous medium and artificial groundwater was used as the background solution. The effectiveness of the monorhamnolipid was compared to that of SDBS, Triton X-100, and ethanol. The results demonstrated the enhancement of dodecane solubility by monorhamnolipid surfactant at concentrations lower than CMC. The concentrations (50–210 μM) are sufficiently low that they do not cause mobilization of the dodecane. Retention of rhamnolipid in the porous medium and detection of nano-size aggregates in the effluent show that the solubilization is based on a sub-CMC aggregate-formation mechanism, which is significantly stronger than the solubilization caused by the co-solvent effect. The rhamnolipid biosurfactant is more efficient for the solubilization compared to the synthetic surfactants. These results indicate a strategy of employing low concentrations of rhamnolipid for surfactant-enhanced aquifer remediation (SEAR), which may overcome the drawbacks of using surfactants at hyper-CMC concentrations.

Synthesis of indium nanoparticles at ambient temperature; simultaneous phase transfer and ripening

The synthesis of size-monodispersed indium nanoparticles via an innovative simultaneous phase transfer and ripening method is reported. The formation of nanoparticles occurs in a one-step process instead of well-known two-step phase transfer approaches. The synthesis involves the reduction of InCl₃ with LiBH₄ at ambient temperature and although the reduction occurs at room temperature, fine indium nanoparticles, with a mean diameter of 6.4 ± 0.4 nm, were obtained directly in non-polar n-dodecane. The direct synthesis of indium nanoparticles in n-dodecane facilitates their fast formation and enhances their size-monodispersity. In addition, the nanoparticles were highly stable for more than 2 months. The nanoparticles were characterised by dynamic light scattering (DLS), small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy to determine their morphology, structure and phase purity.

Near room-temperature thermocatalysis: a promising avenue for the degradation of polyethylene using NiCoMnO4 powders

Low-temperature thermocatalytic degradation of LDPE is successfully achieved by NiCoMnO₄ powders.

Influence of Ligand Shell Composition upon Interparticle Interactions in Multifunctional Nanoparticles

The interactions of nanoparticles with biomolecules, surfaces, or other nanostructures are dictated by the nanoparticle's surface chemistry. Thus, far, shortcomings of syntheses of nanoparticles with defined ligand shell architectures have limited our ability to understand how changes in their surface composition influence reactivity and assembly. We report new synthetic approaches to systematically control the number (polyvalency), length, and steric interactions of omega-functionalized (targeting) ligands within an otherwise passivating (diluent) ligand shell. A mesofluidic reactor was used to prepare nanoparticles with the same core diameter for each of the designed ligand architectures. When the targeting ligands are malonamide groups, the nanoparticles assemble via cross-linking in the presence of trivalent lanthanides. We examined the influence of ligand composition on assembly by monitoring the differences in optical properties of the cross-linked and free nanoparticles. Infrared spectroscopy, electron microscopy, and solution small-angle X-ray scattering provided additional insight into the assembly behavior. Lower (less than 33%) malonamide ligand densities (where the binding group extends beyond the periphery of diluent ethylene glycol ligands) produce the strongest optical responses and largest assemblies. Surprisingly, nanoparticles containing a higher surface number of targeting ligand did not produce an optical response or assemble, underscoring the importance of an informed mixed ligand strategy for highest nanoparticle performance.

Nanoparticle dosage-a nontrivial task of utmost importance for quantitative nanosafety research

For a detailed and correct understanding of effects of colloidal nanoparticles exposed to organisms, a correlation of such effects to the physicochemical properties of the nanoparticles is a necessity. Such correlation is complex by the fact that many physicochemical parameters such as size, shape, surface charge, and colloidal stability are interlinked, and nontrivial to experimentally determine. This review aims to give an overview regarding such correlations. Particular focus will be given on the role of determining nanoparticle concentrations, which is the basis for most quantitative toxicity evaluations. A comparison of mass versus particle number concentrations is given, and their respective differences are highlighted. WIREs Nanomed Nanobiotechnol 2016, 8:479-492. doi: 10.1002/wnan.1378 For further resources related to this article, please visit the WIREs website.

Core-Shell Structure of Monodisperse Poly(ethylene glycol)-Grafted Iron Oxide Nanoparticles Studied by Small-Angle X-ray Scattering

The promising applications of core-shell nanoparticles in the biological and medical field have been well investigated in recent years. One remaining challenge is the characterization of the structure of the hydrated polymer shell. Here we use small-angle X-ray scattering (SAXS) to investigate iron oxide core-poly(ethylene glycol) brush shell nanoparticles with extremely high polymer grafting density. It is shown that the shell density profile can be described by a scaling model that takes into account the locally very high grafting density near the core. A good fit to a constant density region followed by a star-polymer-like, monotonously decaying density profile is shown, which could help explain the unique colloidal properties of such densely grafted core-shell nanoparticles. SAXS experiments probing the thermally induced dehydration of the shell and the response to dilution confirmed that the observed features are associated with the brush and not attributed to structure factors from particle aggregates. We thereby demonstrate that the structure of monodisperse core-shell nanoparticles with dense solvated shells can be well studied with SAXS and that different density models can be distinguished from each other.

Recovering the size of nanoparticles by digital in-line holography

The development of methods to measure the size of nanoparticles is a challenging topic of research. The proposed method is based on the metrology of the stable vapor bubble created by thermal coupling between a laser pulse and the nanoparticle in a droplet. The measurement is realized by digital in-line holography. The size of the nanoparticle is deduced from numerical simulations computed with a photo-thermal finite element method.

Aggregation of low-concentration dirhamnolipid biosurfactant in electrolyte solution

Cryo-transmission electron microscopy tests show aggregate formation for dirhamnolipid biosurfactant at concentrations lower than surface-tension-based critical micelle concentration (CMC_st).

Ionic nanoparticle networks: development and perspectives in the landscape of ionic liquid based materials

This article summarizes the research performed on ionic nanoparticle networks compared with other hybrid materials like ionogels or imidazolium modified nanoparticles.

SAXS characterization of polymer-embedded hollow nanoparticles and of their shell porosity

Size parameters of SiO2/TiO2hollow nanoparticles (HNPs) of 25–100 nm in diameter were characterized by small-angle X-ray scattering (SAXS). On the basis of the decoupling and the Percus–Yevick approximations, and using a hollow sphere model, size information on HNPs was extracted, including average outer diameter, average inner diameter and polydispersity. Application of an alternative form factor based on hollow ellipsoids, and of a sticky hard sphere structure factor, did not improve the fit significantly. The shell porosity of the HNPs and the size of the pores in the HNP shell were further characterized by combining SAXS with gas adsorption methods. The above HNPs were then supported on a porous poly(ethylene oxide) scaffold by freeze drying from aqueous solution. To characterize the product, a multishell model was applied to fit the experimental SAXS curves and extract the following morphological information: distribution of HNPs between the surface and interior of the polymer, thickness of the polymer layers lining the outer and inner surfaces of HNPs, and densities of the outer and inner polymer layers. The work demonstrates the versatility of SAXS in obtaining key information on dissolved and polymer-supported HNPs in applications such as drug delivery and catalysis.

Capacity of mesoporous bioactive glass nanoparticles to deliver therapeutic molecules

Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 μg ml(-1). Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration.

Characterizing size and porosity of hollow nanoparticles: SAXS, SANS, TEM, DLS, and adsorption isotherms compared

A combination of experimental methods, including transmission and grazing incidence small-angle X-ray scattering (SAXS and GISAXS), small-angle neutron scattering (SANS), transmission electron microscopy (TEM), dynamic light scattering (DLS), and N(2) adsorption-desorption isotherms, was used to characterize SiO(2)/TiO(2) hollow nanoparticles (HNPs) of sizes between 25 and 100 nm. In the analysis of SAXS, SANS, and GISAXS data, the decoupling approximation and the Percus-Yevick structure factor approximation were used. Brunauer-Emmett-Teller, t-plot, and a spherical pore model based on Kelvin equation were applied in the treatment of N(2) isotherms. Extracted parameters from the scattering and TEM methods are the average outer and inner diameters and polydispersity. Good agreement was achieved between different methods for these extracted parameters. Merits, advantages, and disadvantages of the different methods are discussed. Furthermore, the combination of these methods provided us with information on the porosity of the shells of HNPs and the size of intrawall pores, which are critical to the applications of HNPs as drug delivery vehicles and catalyst supports.

Nanoparticle assemblies as probes for self-assembled monolayer characterization: correlation between surface functionalization and agglomeration behavior

The ordering of dodecyl chains has been investigated in mixed monolayers of phosphonic acid capping agents on the surface of hydrothermally prepared zirconia nanocrystals. Methyl-, phenyl-, pyryl-, and tert-butylphosphonic acids have been used to investigate series with different mixing ratios with dodecylphosphonic acid as the cocapping agent for the mixed monolayer formation. Fourier transform infrared (FTIR) studies revealed that an increasing amount (different for each type) of coadsorbed capping agent reduces the ordering of the dodecyl chains significantly. Small-angle X-ray scattering (SAXS) verified that with increasing amount of cocapping agent the agglomeration of the particles decreases. The strong correlation of the agglomeration behavior with the ordering of the surface-bound alkyl chains leads to the conclusion that interparticle bilayers, formed via long alkyl chain packing, are responsible and can be controlled on a molecular level by coadsorbing various molecules. On the basis of this correlation, nanoparticles can be used as probes for self-assembled monolayer investigation by an indirect structural method (SAXS) and correlated with the routine spectroscopical method for the chemical analysis of surface groups (FTIR).