Impedimetric Sensor for SARS-CoV-2 Spike Protein Detection: Performance Assessment with an ACE2 Peptide-Mimic/Graphite Interface.

The COVID-19 pandemic has prompted the need for the development of new biosensors for SARS-CoV-2 detection. Particularly, systems with qualities such as sensitivity, fast detection, appropriate to large-scale analysis, and applicable in situ, avoiding using specific materials or personnel to undergo the test, are highly desirable. In this regard, developing an electrochemical biosensor based on peptides derived from the angiotensin-converting enzyme receptor 2 (ACE2) is a possible answer.

Synthesis and Characterization of Iridium(III) Complexes with Substituted Phenylimidazo(4,5-)1,10-phenanthroline Ancillary Ligands and Their Application in LEC Devices.

In this work, we report on the synthesis and characterization of six new iridium(III) complexes of the type [Ir(C^N)(N^N)] using 2-phenylpyridine (-) and its fluorinated derivative (-) as cyclometalating ligands (C^N) and R-phenylimidazo(4,5-)1,10-phenanthroline (R = H, CH, F) as the ancillary ligand (N^N). These luminescent complexes have been fully characterized through optical and electrochemical studies. In solution, the - series exhibits quantum yields (Ф) twice as high as the - series, exceeding 60% in dichloromethane and where MLCT/LLCT and LC emissions participate in the phenomenon.

Dynamic susceptibility of FeO nanotubes.

In this work we performed a detailed numerical analysis to investigate the dynamic susceptibility of 1000 nm long FeO nanotubes by varying the diameter, the tube wall thickness and the magnitude of the external magnetic field applied along the tube axis. We found two well-defined modes, one of low frequency associated with the caps of the nanotubes, and another of high frequency associated with the central area of the nanotubes, which can be controlled by varying the geometry of the tubes or the external magnetic field to which they are subjected. These results allow us to suggest the use of these nanotubes in applications that require controlling the resonant frequency in the GHz range.

Hollow Iron Oxide Nanospheres Obtained through a Combination of Atomic Layer Deposition and Electrospraying Technologies.

In the present study, we report on the successful synthesis of hollow iron oxide nanospheres. The hollow FeO nanospheres were synthesized following a four-step procedure: electrospraying spherical PVP particles, coating these particles with alumina (AlO) and hematite (FeO) through atomic layer deposition and, finally, a thermal reduction process to degrade the polymer (PVP) and convert hematite (FeO) into magnetite (FeO). A structural analysis using X-ray diffraction (XRD) confirmed the effectiveness of the thermal reduction process.

Controlled dispersion of ZnO nanoparticles produced by basic precipitation in solvothermal processes.

Zinc oxide nanoparticles were successfully synthesized under precipitation processes, using ZnSO·7HO as a Zn precursor and KCO used as a basic source, and hydrozincite was obtained as an intermediary, which was treated under two procedures; first procedure involved multiple stages to get final precipitated with NaOH, and in the second procedure the hydrozincite was straightforwardly dried at 220 °C. By both processes ZnO structures were obtained, which were turned into nanoparticles by a solvothermal treatment, for four hours in ethylene glycol at 200 °C. The final products for the first procedure was conglomerate of spherical nanoparticles with sizes ranged between 5-10 nm and dispersed ellipsoidal nanoparticles for the second procedure.

Stabilization of Magnetic Skyrmions on Arrays of Self-Assembled Hexagonal Nanodomes for Magnetic Recording Applications.

Magnetic skyrmions are nontrivial spin textures that resist external perturbations, being promising candidates for the next-generation recording devices. Nevertheless, a major challenge in realizing skyrmion-based devices is the stabilization of ordered arrays of these spin textures under ambient conditions and zero applied field. Here, we demonstrate for the first time the formation and stabilization of magnetic skyrmions on the arrays of self-assembled hexagonal nanodomes taking advantage of the intrinsic properties of its curved geometry.

Magnetic properties of FeO antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction.

Magnetic films of magnetite (FeO) with controlled defects, so-called antidot arrays, were synthesized by a new technique called AFIR. AFIR consists of the deposition of a thin film by atomic layer deposition, the generation of square and hexagonal arrays of holes using focused ion beam milling, and the subsequent thermal reduction of the antidot arrays. Magnetic characterizations were carried out by magneto-optic Kerr effect measurements, showing the enhancement of the coercivity for the antidot arrays.

Improvement of Polylactide Properties through Cellulose Nanocrystals Embedded in Poly(Vinyl Alcohol) Electrospun Nanofibers.

Electrospun nanofibers of poly (vinyl alcohol) (PV) were obtained to improve dispersion of cellulose nanocrystals (CNC) within hydrophobic biopolymeric matrices, such as poly(lactic acid) (PLA). Electrospun nanofibers (PV/CNC) were successfully obtained with a final concentration of 23% (/) of CNC. Morphological, structural and thermal properties of developed CNC and electrospun nanofibers were characterized.

Temperature-dependent magnetic properties of Ni nanotubes synthesized by atomic layer deposition.

Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere.

Single-crystal growth of nickel nanowires: influence of deposition conditions on structural and magnetic properties.

This paper examines the influence of electrodeposition potential, pore size, pH, composition, and temperature of the electrolytic bath on the structure of nickel nanowires arrays electrodeposited into anodic alumina oxide porous membranes. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analysis were employed to characterize the structural and morphological properties of the nanowires. Results show that the electrodeposition potential controls the growth of nickel nanowires along some preferential crystallographic planes.