MXenes with ordered triatomic-layer borate polyanion terminations.

Surface terminations profoundly influence the intrinsic properties of MXenes, but existing terminations are limited to monoatomic layers or simple groups, showing disordered arrangements and inferior stability. Here we present the synthesis of MXenes with triatomic-layer borate polyanion terminations (OBO terminations) through a flux-assisted eutectic molten etching approach. During the synthesis, Lewis acidic salts act as the etching agent to obtain the MXene backbone, while borax generates BO species, which cap the MXene surface with an O-B-O configuration.

Comparative Analysis of Metal Electrodeposition Rates towards Formation of High-Entropy WFeCoNiCu Alloy.

This study presents a calculation and comparison of Fe, Co, Ni and Cu deposition rates in the tungsten codeposition process based on the electrodeposition of numerous tungsten alloys. Eight different tungsten alloys containing from two to five metals were electrodeposited in constant conditions in order to compare the exact reduction rates. The calculated rates enabled control of the alloy composition precise enough to obtain a high-entropy WFeCoNiCu alloy with a well-balanced composition.

Removal of doxorubicin hydrochloride and crystal violet from aqueous solutions using spray-dried niobium oxide coated with chitosan-activated carbon: Experimental and DFT calculations.

Spray-dried niobium oxide coated with chitosan-activated carbon (NIC) was synthesized and used to remove doxorubicin hydrochloride and crystal violet from aqueous solutions under different parameters such as solution pH (2, 4, 6, and 8), contact time (1 to 9 h), initial concentration (20 to 200 mg L), and competing ions (0.1 M of CaCl and NaCl). The addition of 5 % chitosan-activated carbon to the matrix of niobium oxide slightly increased the specific surface area from 26 to 30 m g, with the introduction of a carboxylic functional group.

Application of biocompatible and ultrastable superparamagnetic iron(III) oxide nanoparticles doped with magnesium for efficient magnetic fluid hyperthermia in lung cancer cells.

Magnetic fluid hyperthermia (MFH) is a promising therapeutic strategy that targets malignant tissues by heating to 40-43 °C using magnetic nanoparticles (MNPs) subjected to an alternating magnetic field (AMF). In this study, novel magnetic iron(III) oxide nanoparticles doped with magnesium (Mg-γ-FeO(mPEG-silane)) were synthesized, and their structural, chemical, and magnetic properties were analyzed using the following techniques: Fourier-transform infrared spectroscopy, Raman spectroscopy, vibrating magnetometer analysis, powder X-ray diffraction, inductively coupled plasma mass spectrometry, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The as-synthesized MNPs were used as water ferrofluids for MFH under an AMF in two calorimetric setups, namely phantom and lung cancer cell (A549) models.

Exosomes derived from lung cancer cells: Isolation, characterization, and stability studies.

Recent advances in nanomedicine have paved the way for developing targeted drug delivery systems. Nanoscale exosomes are present in almost every body fluid and represent a novel mechanism of intercellular communication. Because of their membrane origin, they easily fuse with cells, acting as a natural delivery system and maintaining the bioactivity and immunotolerance of cells.

STEM Tomography of Au Helical Assemblies.

Composite, helical nanostructures formed using cooperative interactions of liquid crystals and Au nanoparticles were studied using a scanning transmission electron microscopy (STEM) mode. The investigated helical assemblies exhibit long-range hierarchical order across length scales, as a result of the crystallization (freezing) directed growth mechanism of nanoparticle-coated twisted nanoribbons and their ability to form organized bundles. Here, STEM methods were used to reproduce the 3D structure of the Au nanoparticle double helix.

Enantioselective sensing of (S)-Thalidomide in blood plasma with a chiral naphthalene diimide derivative.

Fast, simple in use and highly effective voltammetric enantiosensor dedicated for determination of thalidomide (TD) enantiomers (especially towards the toxic (S)-enantiomer) in blood plasma is still desirable. Here we have proven that newly synthesized chiral naphthalene diimide (NDI) derivatives are excellent electroactive materials for TD enantiosensors. The recognition process relies on the specific interaction between the chiral NDI receptor and the thalidomide enantiomer of the opposite configuration.

Preparation of Pt-skin PtRhNi Nanoframes Decorated with Small SnO Nanoparticles as an Efficient Catalyst for Ethanol Oxidation Reaction.

Pt-based nanoframes are one of the most promising catalysts for ethanol oxidation reaction in direct ethanol fuel cells. It is important to understand the mechanisms responsible for creating these hollow nanoframe-based catalysts. Herein, for the first time, Pt-skin PtRhNi rhombic dodecahedral nanoframes were decorated with small SnO nanoparticles and were used as an efficient catalyst for the ethanol oxidation reaction.

Reduced graphene oxide doping with nanometer-sized ferrocene moieties - New active material for glucose redox sensors.

Herein, we present that the reduced graphene oxide (rGO) doped with nanometer-sized ferrocene moieties is a new, excellent active material for redox sensors. Two distinct approaches were utilized for the modification of rGO. The first method was based on the covalent decoration of rGO via the addition of azomethine ylide generated from the ferrocenecarboxaldehyde oxime.

Physical and chemical changes in Alhydrogel™ damaged by freezing.

Accidental freezing of aluminum-based vaccines occurs during their storage and transportation, in both developed and developing countries. Freezing damages the freeze-sensitive aluminum adjuvanted vaccines, through separation of lattice between aluminum adjuvant and antigen, leading to formation of aluminum aggregates, and loss of potency. In this study, we examined Alhydrogel™ ([AlO(OH)]xnHO, aluminum hydroxide, hydrated for adsorption) stored under recommended conditions, and exposed to freezing temperature until solid-frozen.

Single-step synthesis of Er and Yb ions doped molybdate/GdO core-shell nanoparticles for biomedical imaging.

Nanostructures as color-tunable luminescent markers have become major, promising tools for bioimaging and biosensing. In this paper separated molybdate/GdO doped rare earth ions (erbium, Er and ytterbium, Yb) core-shell nanoparticles (NPs), were fabricated by a one-step homogeneous precipitation process. Emission properties were studied by cathodo- and photoluminescence.

Electrochemical examination of ability of dsDNA/PAM composites for storing and releasing of doxorubicin.

Composites consisting of ss- and ds-DNA strands and polyacrylamide (PAM) hydrogel have been synthesized. DNA was entrapped non-covalently. The obtained DNA biomaterial exhibited a strong increase in guanine and adenine anodic currents when temperature reached the physiological level.

A novel type of electrochemical sensor based on ferromagnetic carbon-encapsulated iron nanoparticles for direct determination of hemoglobin in blood samples.

An effective, fast, facile and direct electrochemical method of determination of hemoglobin (Hb) in blood sample without any sample preparation is described. The method is accomplished by using the ferromagnetic electrode modifier (carbon-encapsulated iron nanoparticles) and an external magnetic field. The successful voltammetric determination of hemoglobin is achieved in PBS buffer as well as in the whole blood sample.

Tannic acid modified silver nanoparticles show antiviral activity in herpes simplex virus type 2 infection.

The interaction between silver nanoparticles and herpesviruses is attracting great interest due to their antiviral activity and possibility to use as microbicides for oral and anogenital herpes. In this work, we demonstrate that tannic acid modified silver nanoparticles sized 13 nm, 33 nm and 46 nm are capable of reducing HSV-2 infectivity both in vitro and in vivo. The antiviral activity of tannic acid modified silver nanoparticles was size-related, required direct interaction and blocked virus attachment, penetration and further spread.

Hydrogel with chains functionalized with carboxyl groups as universal 3D platform in DNA biosensors.

Application of hydrogel based on N-isopropylacrylamide with carboxyl groups grafted to the chains enabled the immobilization of DNA at an extent exceeding that for flat surfaces by at least one order of magnitude. The probe DNA strands in the 3D platform were fully available for the hybridization process. The examination of the gels containing different amounts of grafted carboxyl groups (1-10%) was done using quartz crystal microbalance, electrochemical impedance spectroscopy, chronoamperometry and ionic coupled plasma with laser ablation.

Progress in targeting tumor cells by using drug-magnetic nanoparticles conjugate.

To limit cytotoxicity of anticancer drugs against healthy cells, an appropriate carrier should be synthesized to deliver the drug to the tumor tissue only. A good solution is to anchor a magnetic nanoparticle to the molecule of the drug and to use a properly directed external magnetic field. The synthesis of the conjugate of doxorubicin with magnetic nanoparticles (iron oxide) modified by us resulted in a substantial depression of the aggregation process of the nanoparticles and therefore allowed the correct examination of cytotoxicity of the modified drug.

Polyacrylate microspheres composite for all-solid-state reference electrodes.

A novel concept is proposed for the encapsulation of components within polyacrylate microspheres, prior to their incorporation into a membrane phase. Thus finer and better controlled dispersion of heterogeneous membrane components can be achieved. This concept was verified by using a poly(n-butyl acrylate) membrane-based reference electrode as an example.

Substantial difference between temperature dependencies of dsDNA predenaturation process obtained by voltammetry and spectroscopy.

The electrooxidation of double stranded DNA has been studied in a wide temperature range by cyclic and square wave voltammetries and the results were compared with UV-Vis and CD spectroscopies. A twofold increase of dsDNA voltammetric peaks related to the conformation changes preceding the denaturation process was found to begin at a temperature lower than the well known increase of dsDNA absorbance upon denaturation (the melting point) by circa 20 degrees C. Since the dsDNA voltammetric peaks are related directly to the electrooxidation of guanine and adenine, early conformational changes in guanine-cytosine (G-C) and adenine-thymine (A-T) pairs in dsDNA are possible reasons for the increase of the voltammetric peaks.

Modification of electrode surfaces: deposition of thin layers of polypyrrole--Au nanoparticle materials using a combination of interphase synthesis and dip-in method.

Formation of thin layers of the composite material by a method based on interphase polymerization induced by a transport-controlled redox reaction is described. The obtained films were of 0.2-1 microm thickness, consisted of polypyrrole and gold nanoparticles (up to 13.

Influence of a magnetic nanoparticle as a drug carrier on the activity of anticancer drugs: interactions of double stranded DNA and doxorubicin modified with a carrier.

Magnetic drug targeting executed by nanoparticles as carriers is a promising cancer treatment which avoids the side effects of conventional chemotherapy. We have modified doxorubicin with magnetic nanoparticles. Doxorubicin (adriamycin) is a potential anticancer drug yet nonspecific in its antibiotic action.

Electroanalytical and spectroscopic procedures for examination of interactions between double stranded DNA and intercalating drugs.

A method is presented for the electroanalytical characterization of interactions of dsDNA with a drug, under conditions that both agents are dissolved in the phosphate buffer solution and both are electroactive. Normal pulse, square wave, differential pulse, and cyclic voltammetries were employed in the measurements of the drug and dsDNA oxidation signals at carbon electrodes. UV-Vis spectroscopy was used as a non-electrochemical method to support the electroanalytical data.

Electrodeposition of poly(N-vinylcarbazole) at the three-phase junction. Formation of very different polymer structures.

Poly(N-vinylcarbazole) films can be deposited at the three-phase boundary when the organic phase contains only monomer, N-vinylcarbazole, while the aqueous phase contains supporting electrolyte. A cylindrical platinum microelectrode is immersed into the two-liquid system in such a way that a part of it is located in one liquid and the other part resides in the second liquid. The thickness of the reaction layer, or the width of the microelectrode zone where the polymer grows, depends on the kind of ions present in the aqueous phase and the time of the experiment.

Electrooxidation of dissolved dsDNA backed by in situ UV-Vis spectroscopy.

The electrooxidation of double-stranded DNA (dsDNA) from calf thymus was carried by using cyclic voltammetry. A glassy carbon disk-, a platinum disk-, a platinum mesh- and a carbon vapor-deposited platinum mesh electrodes were used. It is shown that the appropriate chemical and biological (steam treatment) purification of the complete cell allows, for the graphite electrode, formation of a wide anodic dsDNA signal with two visible anodic peaks.

Effect of change in angle between microelectrode surface and jet direction in flow system on current response in solutions of different ionic strength.

The influence of stream orientation versus surface of microelectrode detector was examined in the range between vertical and parallel flow for various jet velocities and various levels of supporting electrolyte. The flow cell was equipped with a conical body Pt microdisk electrode, and the measurements involved voltammetry and chronoamperometry. Ferrocene, two its charged derivatives (sodium ferrocenylo sulfate and ferrocenylomethyltrimethylamino hexafluorophosphate) and sodium iodide were employed as the substrates in the experiments.