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The text is an editorial from the Journal of Materials Science discussing a cover paper titled "High-performance, water-resistant and ion-conducting gel used as underwater ECG electrodes" by Shi et al. The paper addresses the challenges of sensing underwater and describes the synthesis and characterization of a single-layer hydrogel electrode that is resistant to swelling in water. The paper is accessible to non-experts and includes photographs, curves, and electrocardiograms to support the findings. Although the article is not open access, it can be accessed through a SharedIt link provided by the publisher. [Extracted from the article]

The hydrogel in this paper is designed to do just that, by using controlled release from a hydrogel to deliver the drug quickly and at a relatively high concentration to the interior of cancer cells. The paper describes the synthesis and in-vitro testing of a hydrogel composite that is designed to maximize toxicity to cancer cells by both efficiently delivering the cancer drug doxorubicin (DOX) and overheating the cells with magnetically induced hyperthermia. This makes it highly desirable to develop a delivery system that can encapsulate the drug, bring the drug directly to the cancer cells then release the drug into the cancer tumor or cells. [Extracted from the article]

A droplet forming microfluidic chip was used to create droplets of precisely controlled size that contained a photocurable monomer as well as nanoparticles of magnetite and manganese dioxide. Manganese dioxide nanoparticles were shown to be effective for decomposing hydrogen peroxide to form oxygen bubbles that provided propulsion, which increased the rate of methylene blue decomposition by the magnetite nanoparticles through enhanced mixing. Dissolving the alginate fiber released the microparticles that contain base-metal catalysts for both the decomposition of hydrogen peroxide, and methylene blue, a common water contaminant [[2]]. [Extracted from the article]

This work describes a technique forforming high-density arraysand patterns of membrane-bound proteins through binding to a curvature-organizedcompositional pattern of metal-chelating lipids (Cu2+-DOIDAor Cu2+-DSIDA). In this bottom-up approach, the underlyingsupport is an e-beam formed, square lattice pattern of hemispheres.This curvature pattern sorts Cu2+-DOIDA to the 200 nm hemisphericallattice sites of a 600 nm × 600 nm unit cell in Ld- Lophase separated lipid multibilayers. Binding ofhistidine-tagged green fluorescent protein (His-GFP) creates a highdensity array of His-GFP-bound pixels localized to the square latticesites. In comparison, the negative pixel pattern is created by sortingCu2+-DSIDA in Ld- Lβ′phase separated lipid multibilayers to the flat grid between thelattice sites followed by binding to His-GFP. Lattice defects in theHis-GFP pattern lead to interesting features such as pattern circularity.We also observe defect-free arrays of His-GFP that demonstrate perfectarrays can be formed by this method suggesting the possibility ofusing this approach for the localization of various active moleculesto form protein, DNA, or optically active molecular arrays. [ABSTRACT FROM AUTHOR]

Abstract: Magnetite nanoparticles (Chemicell SiMAG-TCL) were characterized by SQUID-relaxometry, susceptometry, and TEM. The magnetization detected by SQUID-relaxometry was 0.33% of that detected by susceptometry, indicating that the sensitivity of SQUID-relaxometry could be significantly increased through improved control of nanoparticle size. The relaxometry data were analyzed by the moment superposition model (MSM) to determine the distribution of nanoparticle moments. Analysis of the binding of CD34-conjugated nanoparticles to U937 leukemia cells revealed 60,000 nanoparticles per cell, which were collected from whole blood using a prototype magnetic biopsy needle, with a capture efficiency of >65% from a 750μl sample volume in 1min. [Copyright &y& Elsevier]

We describe the synthesis of highly magnetic iron nanoparticles using a novel surfactant, a β-diketone. We have produced 6 nm iron nanoparticles with an unusually high saturation magnetization of more than 80% the value of bulk iron. Additionally, we measured a particle susceptibility of 14 (MKS units), which is far above the value possible for micron-scale spherical particles. These properties will allow for formation of composites that can be highly structured by magnetic fields. [Copyright &y& Elsevier]

A microfluidic device has been developed that can adsorb proteins from solution, hold them with negligible denaturation, and release them on command. The active element in the device is a 4-nanometer-thick polymer film that can be thermally switched between an antifouling hydrophilic state and a protein-adsorbing state that is more hydrophobic. This active polymer has been integrated into a microfluidic hot plate that can be programmed to adsorb and desorb protein monolayers in less than 1 second. The rapid response characteristics of the device can be manipulated for proteomic functions, including preconcentration and separation of soluble proteins on an integrated fluidics chip. [ABSTRACT FROM AUTHOR]

Core-shell nanostructures are promising candidates for the next generation of catalysts due to synergistic effects which can arise from having two active species in close contact, leading to increased activity. Likewise, catalysts displaying added functionality, such as a magnetic response, can have increased scientific and industrial potential. Here, Pd/Fe3O4 core-shell nanowire clusters are synthesized and applied as hydrogenation catalysts for an industrially important hydrogenation reaction: the conversion of acetophenone to 1-phenylethanol. During synthesis, the palladium nanowires self-assemble into clusters which act as a high-surface-area framework for the growth of a magnetic iron oxide shell. This material demonstrates excellent catalytic activity due to the presence of palladium while the strong magnetic properties provided by the iron oxide shell enable facile catalyst recovery. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "Tailorable, visible light emission from silicon nanocrystals,” by Dale Huber, Jess Wilcoxon, and George Samara from issue 74 (1999).

Abstract: We use dynamic susceptometry measurements to extract semiempirical temperature-dependent, 255–400K, magnetic parameters that determine the behavior of single-core nanoparticles useful for SQUID relaxometry in biomedical applications. Volume susceptibility measurements were made in 5K degree steps at nine frequencies in the 0.1–1000Hz range, with a 0.2mT amplitude probe field. The saturation magnetization (M s ) and anisotropy energy density (K) derived from the fitting of theoretical susceptibility to the measurements both increase with decreasing temperature; good agreement between the parameter values derived separately from the real and imaginary components is obtained. Characterization of the Néel relaxation time indicates that the conventional prefactor, 0.1ns, is an upper limit, strongly correlated with the anisotropy energy density. This prefactor decreases substantially for lower temperatures as K increases. We find, using the values of the parameters determined from the real part of the susceptibility measurements at 300K, that SQUID relaxometry measurements of relaxation and excitation curves on the same sample are well described. [ABSTRACT FROM AUTHOR]

Controlling the formation of nanosized branched nanoparticles with high uniformity is one of the major challenges in synthesizing nanocatalysts with improved activity and stability. Using a cubic‐core hexagonal‐branch mechanism to form highly monodisperse branched nanoparticles, we vary the length of the nickel branches. Lengthening the nickel branches, with their high coverage of active facets, is shown to improve activity for electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF), as an example for biomass conversion. [ABSTRACT FROM AUTHOR]

Die Kontrolle der Bildung von verzweigten Nanopartikeln mit hoher Homogenität ist eine der größten Herausforderungen bei der Herstellung von Nanokatalysatoren mit verbesserter Aktivität und Stabilität. Mithilfe eines Mechanismus unter Nutzung eines kubischen Kerns und hexagonaler Verzweigung zur Bildung hochgradig monodisperser verzweigter Nanopartikel wurde die Länge der Nickelverzweigungen variiert. Es hat sich gezeigt, dass die Verlängerung der Nickelzweige mit ihrer hohen Bedeckung der aktiven Facetten die Aktivität für die elektrokatalytische Oxidation von 5‐Hydroxymethylfurfural (HMF) als Beispiel für die Umwandlung von Biomasse verbessert. [ABSTRACT FROM AUTHOR]

Background: Novel methods are necessary to reduce morbidity and mortality of patients suffering from infections with Pseudomonas aeruginosa. Being the most common infectious species of the Pseudomonas genus, P. aeruginosa is the primary Gram-negative etiology responsible for nosocomial infections. Due to the ubiquity and high adaptability of this species, an effective universal treatment method for P. aeruginosa infection still eludes investigators, despite the extensive research in this area. Results: We report bacterial inhibition by iron-oxide (nominally magnetite) nanoparticles (NPs) alone, having a mean hydrodynamic diameter of ~ 16 nm, as well as alginate-capped iron-oxide NPs. Alginate capping increased the average hydrodynamic diameter to ~ 230 nm. We also investigated alginate-capped iron-oxide NP-drug conjugates, with a practically unchanged hydrodynamic diameter of ~ 232 nm. Susceptibility and minimum inhibitory concentration (MIC) of the NPs, NP-tobramycin conjugates, and tobramycin alone were determined in the PAO1 bacterial colonies. Investigations into susceptibility using the disk diffusion method were done after 3 days of biofilm growth and after 60 days of growth. MIC of all compounds of interest was determined after 60-days of growth, to ensure thorough establishment of biofilm colonies. Conclusions: Positive inhibition is reported for uncapped and alginate-capped iron-oxide NPs, and the corresponding MICs are presented. We report zero susceptibility to iron-oxide NPs capped with polyethylene glycol, suggesting that the capping agent plays a major role in enabling bactericidal ability in of the nanocomposite. Our findings suggest that the alginate-coated nanocomposites investigated in this study have the potential to overcome the bacterial biofilm barrier. Magnetic field application increases the action, likely via enhanced diffusion of the iron-oxide NPs and NP-drug conjugates through mucin and alginate barriers, which are characteristic of cystic-fibrosis respiratory infections. We demonstrate that iron-oxide NPs coated with alginate, as well as alginate-coated magnetite–tobramycin conjugates inhibit P. aeruginosa growth and biofilm formation in established colonies. We have also determined that susceptibility to tobramycin decreases for longer culture times. However, susceptibility to the iron-oxide NP compounds did not demonstrate any comparable decrease with increasing culture time. These findings imply that iron-oxide NPs are promising lower-cost alternatives to silver NPs in antibacterial coatings, solutions, and drugs, as well as other applications in which microbial abolition or infestation prevention is sought. [ABSTRACT FROM AUTHOR]

The article reports on the need for soft magnetic materials to improve electric power conversion capabilities. It discusses the use of iron and silicon steel, the promise of soft ferrites and nanocrystalline alloys, and the ongoing search for new materials and improvements to current materials.

Abstract: We present a method for the synthesis and precise size control of magnetic nanoparticles in a reversible magnetic agglomeration mechanism. In this approach, nanoparticles nucleate and grow until a critical susceptibility is reached, in which magnetic attraction overcomes dispersive forces, leading to agglomeration and precipitation. This phase change in the system arrests nanoparticle growth and gives true thermodynamic control over the size of nanoparticles. We then show that increasing the alkyl chain length of the surfactant, and hence increasing steric stabilization, allows nanoparticles to grow to larger sizes before agglomeration occurs. Therefore, simply by choosing the correct surfactant, the size and magnetic properties of iron nanoparticles can be tailored for a particular application. With the continuous addition of the precursor solution, we can repeat the steps of nucleation, growth, and magnetic agglomeration indefinitely, making the approach suitable for large scale syntheses. [ABSTRACT FROM AUTHOR]

Abstract: We present a method for the synthesis and precise size control of magnetic nanoparticles in a reversible magnetic agglomeration mechanism. In this approach, nanoparticles nucleate and grow until a critical susceptibility is reached, in which magnetic attraction overcomes dispersive forces, leading to agglomeration and precipitation. This phase change in the system arrests nanoparticle growth and gives true thermodynamic control over the size of nanoparticles. We then show that increasing the alkyl chain length of the surfactant, and hence increasing steric stabilization, allows nanoparticles to grow to larger sizes before agglomeration occurs. Therefore, simply by choosing the correct surfactant, the size and magnetic properties of iron nanoparticles can be tailored for a particular application. With the continuous addition of the precursor solution, we can repeat the steps of nucleation, growth, and magnetic agglomeration indefinitely, making the approach suitable for large scale syntheses. [ABSTRACT FROM AUTHOR]

We report a new assay for breakdown of high molecular weight, insoluble lignin based on lignin films. In this method, decrease in film thickness is detected upon solubilization of mass through either chemical alteration of the lignin or molecular weight reduction. The assay was performed with organosolv lignin, the only chemical modification being an oxidative pretreatment to provide film stability with respect to dissolution. The assay is sensitive to release of as little as 20 Å of material from the film. A multiplexed format was developed using a silicone block in the form of a standard 96-well plate, allowing simultaneous assaying of a large number of reaction conditions. The assay was demonstrated using the Fenton reaction, revealing new insights into the physicochemical aspects of this reaction system with insoluble lignin. In particular, mass solubilized from the film was found to pass through a maximum as a function of the initial concentration of FeCl2 ([FeCl2]o), with the maximum occurring at [FeCl2]o = 1 mM for [H2O2]o = 5%. At that condition, solubilization of mass occurs in two stages. The reaction produces mostly ring-opened products of mass greater than 700 g mol−1, along with a minority of low molecular weight aromatics. The new insight from this work is an important step toward optimizing this complex reaction system for effective lignin breakdown. [ABSTRACT FROM AUTHOR]

Wereport a real time investigation into the effect of seed ageon the growth of gold nanorods using a microfluidic reaction apparatus.Through small-angle X-ray scattering (SAXS) and ultraviolet–visiblespectroscopy (UV–vis) analysis, we observe the seeds agingin accordance with Ostwald ripening. A seed solution is then agedin situ and continuously injected into a microfluidic chip to initiaterod growth. We track nanorod formation in real time using in-lineultraviolet–visible and near-infrared (UV–vis–NIR)monitoring and observe a dramatic decrease in yield with increasingseed age. We then demonstrate that, by diluting the gold seed solutionimmediately following synthesis, the rate of aging can be reducedand nanorods synthesized continuously, in good yield. These findingssuggest ultrasmall, catalytically active seeds, which are rapidlylost due to ripening and are critical for the formation of gold nanorods. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic characterization of spherical, oxide-free, bcc iron nanoparticles synthesized with β-diketone surfactants has been performed. The results of this characterization, which included particles with diameters ranging between 2 and 5nm show that the nanoparticles have an average anisotropy of 1.9×106±0.3×106 J/m3, which is more than an order of magnitude greater than the magnetocrystalline anisotropy of bulk iron. Despite their unusually large anisotropy, these particles can have saturation magnetizations of up to 210Am2/kg (slightly lower than bulk iron). High-energy X-ray diffraction data indicates that the Fe particles have a distorted bcc lattice, which could, at least in part, explain the magnetic behavior of these nanoparticles. Dipolar coupling between particles, while present, is weak and cannot account for the high anisotropy of these nanoparticles. [Copyright &y& Elsevier]

The behavior of iron nanoparticles is heavily influenced by their highly reactive surfaces. A better understanding of organic ligand/particle interactions must be achieved in order to synthesize iron nanoparticles with magnetic saturations ( σ sat) equivalent to bulk iron. Even when synthesized using careful, air-free chemistry techniques and ligands more weakly interacting than those often reported in the literature, the magnetic saturation of iron nanoparticles generally only approaches, but not equals, the magnetic saturation of bulk iron. Here, iron nanoparticles are synthesized using Schlenk line chemistry methods and two different weakly interacting ligands: 2,4-pentanedione and hexaethylene glycol monododecylether. These particles have saturation magnetizations slightly lower than bulk iron, which is believed to be caused by interactions between the passivating ligands and the surface of the nanoparticles. Using X-ray absorption fine structure studies, it is shown that oxidized species of iron exist at the nanoparticles' surface and can be attributed to iron/ligand interaction. The percentage of oxidized species scales with the surface to volume ratio of the nanoparticles, and therefore appears limited to the nanoparticle surface. X-ray absorption fine structure analysis also shows that the nanoparticles have an expanded crystalline lattice, which can further impact their magnetic properties. [ABSTRACT FROM AUTHOR]

X‐ray absorption fine structure experiments reveal the interaction between iron nanoparticles synthesized with both 2,4‐pentanedione and hexaethylene glycol monododecylether ligands, and are presented by Todd Monson and co‐workers on page 258. Oxidized species of iron exist at the nanoparticles' surface and can be attributed to iron/ligand interactions. These oxidized species can play a significant role in the nanoparticles' magnetic properties. [ABSTRACT FROM AUTHOR]