The La x Fe 1− y − z Cu y Pd z O 3 shows activity towards the electrooxidation of methanol along with a CO-resilient surface.

Omethoate (OMT) is a highly effective organophosphorus insecticide that progressively accumulates in the food chain, posing serious risks to human health and ecosystem. Therefore, it is essential to establish a detection method for OMT that combines high sensitivity with strong specificity to support food safety and environmental monitoring. In this study, we used a non-immobilized targeting method based on graphene oxide-based systematic evolution of ligands by exponential enrichment (GO-SELEX) to screen aptamers (APTs) of OMT. After 12 rounds of screening, we successfully obtained APTs with high affinity and specificity. We further verified the binding characteristics of the candidate APTs through fluorescence competition assays, molecular docking simulations, and sequence truncation and optimization. APT-8-1 was identified as the optimal candidate sequence (Kd=22.79±1.13 nM). Using it as a recognition element, we developed a competitive lateral flow assay (LFA) for detection of OMT. Under the optimized conditions, the limit of detection (LOD) was 0.69 μg/L, the detection range was 5-1000 μg/L. For the determination of OMT in vegetable samples, recovery rates were 94.21%-109.70%. These results indicate that the proposed LFA provides a rapid, sensitive, and reliable means for monitoring OMT residues in vegetables, offering a practical tool for food safety surveillance.

Alzheimer's disease (AD) is the leading cause of dementia and a major global health issue, affecting over 50 million people worldwide and projected to rise to 139 million by 2050. The disease is marked by senile plaques (SPs) formed from beta-amyloid (A beta) peptide assemblies and neurofibrillary tangles made of tau protein. Brain changes in AD begin decades before symptoms, making early diagnosis critical for potential intervention. Currently, definitive diagnosis is post-mortem, but imaging methods are being explored for early detection. Among them, MRI, due to its wide accessibility and high resolution, is promising but lacks sensitivity for SPs unless contrast agents (CAs) are used. In that context, we have designed vectorized CAs so that they allow imaging specifically SPs. Iron oxide nanoparticles (IONPs) are suitable T2 MRI CAs due to their biocompatibility, MRI properties, and easy functionalization. Indeed, functionalizing these IONPs with targeting ligands (TLs) specific to SPs is very promising to ensure an early diagnosis of AD. Thus, this study focused on developing a class of MRI CAs by coupling Amylovis-a compound developed to bind specifically to A beta peptides-to dendron-coated IONPs. The TLs, Amylovis, were first demonstrated to have high affinity for A beta in silico, even if coupled to dendronized IONPs. Then, dendronized IONPs were synthesized, and Amylovis was successfully coupled to them: the amount of coupled Amylovis was determined as well as the effect of this coupling on colloidal stability and relaxivity measurements of dendronized IONPs. Finally, dendronized IONPs were demonstrated to interact with A beta 1-40/42 fibers only when they bear the Amylovis TLs. The results thus showed a strong potential for these targeted nanoparticles as MRI CAs for early and specific diagnosis of AD.

Carbon nanostructures (dots) have emerged as a novel and sustainable alternative for the photocatalytic degradation of water pollutants. This work presents the synthesis of multidoped carbon nanomaterials (CNs) using a microwave-assisted method. Overall, four types of carbon nanostructures were obtained: (i) nitrogen-doped CNs (N-CDs), (ii) nitrogen and sulfur co-doped CNs (N,S-CNs), (iii) nitrogen and phosphorus co-doped CNs (N,P-CNs), and (iv) nitrogen, sulfur, and phosphorus multi-doped CNs (N,S,P-CNs). The characterization of these nanoparticles was performed via Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), enabling the identification of stretching modes corresponding to C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O, C-N, and N-H functional groups. Additionally, UV-vis and fluorescence spectroscopies allowed the detection of n-pi* and pi-pi* absorption bands at similar to 325 and 400 nm, along with light emission at 438 nm. High-resolution transmission electron microscopy (TEM) characterization confirmed structural and morphological differences between the nanomaterials, which exhibited sizes ranging from 1 to 100 nm, depending on the chemical composition of the starting precursors. Finally, the photocatalytic activity of the CNs towards the degradation of toluidine blue was assessed, considering the effects of morphology, composition, and both catalyst and dye concentration on photodegradation. Such a catalytic process followed pseudo-first-order kinetics, where N-CDs exhibited the highest potential for toluidine blue degradation. Our results highlight that the photocatalytic activity of carbon nanomaterials is a multifactorial process essentially driven by the formation of OH radicals, where doping and particle morphology also play a combined role in photocatalysis. This work opens a route for understanding the chemical composition and structure of photocatalytic nanocarbons and their application to the degradation of organic pollutants in water, thus offering a sustainable alternative for wastewater treatment.

ZnO nanoparticles functionalized with APTES were obtained to evaluate their CH4 and CO2 adsorption at 298 K in a range between 0 and 10 bar. First, ZnO nanoparticles were obtained by a precipitation method and subsequently coated with (3-aminopropyl)triethoxysilane (APTES). As a preliminary study, the results were compared with previously reported naked nanoparticles in order to evaluate the influence of APTES coating on CO2 selectivity. UV-Vis, FT-IR spectroscopy, TGA, XRD, TEM/EDX, XPS and N2 adsorption at 77 K were used to characterize the evaluated material. It was observed that the amount of gas adsorbed on the surface of the nanostructure was very small in comparison with other materials traditionally used for this purpose but slightly higher than those obtained in naked nanoparticles evaluated in previous studies. The affinity of CO2 for the amines groups of the APTES ligand was also discussed.

In this work, we present the design, fabrication, and automation of a customized and affordable system capable of performing the thin film deposition techniques of Dip-Coating and SILAR at room temperature. To automate the system, parts from disused equipment were reused, new pieces were fabricated through additive manufacturing, and open-source software was also utilized. The device was controlled using an Arduino UNO R3. Additionally, a graphical interface was developed in Python with the PyQt library to adjust the motion settings and transmit parameters to the Arduino via serial communication. We validated the system by fabricating layers of Cu2O and CuO, subsequently comparing their structural and morphological properties with findings previously reported in the literature.

Copper(II) oxide (CuO) nanostructures based solar cells have a great potential due to the optimal absorber characteristic of this material. Furthermore, CuO is stable, composed by abundant elements in the Earth's crust and can be obtained by inexpensive and simple synthesis methods. The substrates seeding is an important technological step with great influence in the morphology of CuO nanorods obtained by the hydrothermal technique. We have studied the influence of dip coating and spin coating as seeding techniques on the CuO nanorods properties. The materials are also evaluated after a sequential annealing until 500 degrees C. The samples were characterized by means of scanning electron microscopy (SEM) and Raman spectroscopy.

The increasing use of cytostatic in cancer therapy, with new antitumor agents, such as copper complexes, has become a serious environmental problem due to their high toxicity, even at low concentrations. Various sorbent materials have been used to remove these contaminants in wastewater. However, these sorbents present some difficulties related to waste management and have a high cost. One of the sorbents with satisfactory results for the retention of heavy metals is the Metalzorb™ sponge. This material is a high porous and economic ion exchange material with selective affinity to retain heavy metals in both cationic and anionic states. Such material is able to promote high rates of adsorption and flexibility, which enables their compressibility into an extremely small volume to facilitate its disposal once the capacity of the material has been exhausted. The objective of this work was the selection of the best conditions for the batch sorption process in Metalzorb™ sponge of trans-[Cu(Cl)2(NH3)2] in dissolution. For this, the synthesis process of the compound and its characterization by Infrared Spectroscopy and X-ray Diffraction were optimized. The best results were obtained for pH 8, in a solution volume of 15 mL, m/V = 1 g L−1 and a contact time of 60 min. The experimental data were adjusted to kinetic and equilibrium models for 25, 50 and 70 °C, obtaining a maximum capacity approximated to 49 mg g−1 meaning a 98% retention in all cases.

Solid-state Pb(II) ion selective electrodes were developed, which are based on 3,3-disubstituted 1-acylthioureas as ionophores and use PVC membranes. 1-Benzoyl, 1-(2-furoyl), 3,3-diethyl and 3,3-diphenyl were the substituent groups on the thioureide core. The analytical parameters for the constructed electrodes were studied. The electrodes based on 3,3-diethyl substituted thiourea derivatives showed better analytical response to Pb(II) ions with suitable sensitivity and an average lifetime of more than 30 days. Cu(II), Hg(II) and Ag(I) ions were interfering species during Pb(II) detection. Scanning electron microscopy and atomic force microscopy micrographs of the activated sensing membranes revealed morphological changes, which have been associated with the performance of the sensors. The studies have suggested that the detection of few large size particles or aggregates at the membrane surface are responsible for inadequate functioning of the prepared electrodes. This pattern was mainly observed for the sensing membranes based on 3,3-diphenyl groups as substituents and is related to unfavorable steric and electronic factors. Furthermore, X-ray photoelectron spectroscopy profiles S2p and Pb4f supported chemically the analytical response displayed for the four membrane systems. The X-ray photoelectron spectroscopy results combined with scanning electron microscopy and atomic force microscopy studies shed light on the working mechanism of the studied electrodes.

Abstract In the last few decades, the use of iron oxide nanoparticles (IONPs) with magnetic properties, especially in biomedicine, has gained a great attention due to the wide range of applications of those systems in various fields. In the present work, iron oxide nanoparticles (IONPs) using β-cyclodextrin (β-CD) as capping agent were synthesized by normal co-precipitation and reverse co-precipitation methods. Syntheses were made at 25 kHz y 45 kHz and without ultrasound for both methods. As-synthetized IONPs were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction, thermal analysis, scanning electron microscopy, transmission electron microscopy, dynamic light scattering (DLS) and electrophoretic light scattering (z potentials). The analyses of vibration sample magnetometer confirmed that the nanoparticles have magnetic properties. Differences in particle size, organic coating degrees, and magnetization values for normal and reverse co-precipitation methods for obtained IONPs were observed. The particle size determined by Scherrer equation, SEM, TEM and DLS was increased at 45 kHz for both methodologies. The z potentials nearby ˗30 mV suggest that nanoparticles dispersion are moderately stable from aggregation. Potential use a platform for magnetic separation of IONPs modified with β-CD obtained by normal co-precipitation method in this work, are analyzed by FT-IR spectroscopy, using as a model IBF, taking in account the formation of inclusion complex between this molecule and the β-CD on the surface of IONPs.

Alzheimer's disease is characterized by an early aggregation of amyloid plaques in the brain, principally composed of beta amyloid peptides (βA). These structures could be visualized with the appropriate sensitivity and resolution by Magnetic Resonance Imaging (MRI), for which it is necessary contrast agents functionalized with compounds with high affinity to βA. Today, in the clinic, the implementation of metal oxide nanoparticles as contrast agents are an interesting research field. The goal of this work is to obtain, by polyol method, gadolinium(III) oxide nanoparticles (Gd2O3NPs) conjugated with Amylovis®, a family of naphthyl derivate compounds, obtained by the Cuban Center for Neurosciences, that has shown affinity for βA. The Gd2O3NPs were synthetized by the polyol method and functionalized with terminal carboxyl groups, for later conjugation with Amylovis®, through the Steglich reaction, (Gd2O3@PEGdiCOOHx-Amylovis®NPs). Gd2O3NPs were purified by dialysis and ultrafiltration and characterized by FT-IR, DLS and TEM. The relaxivity values and its gadolinium content were estimated by RMI. Gd2O3@PEGdiCOOHx-Amylovis®NPs obtained showed a near band to 1639 cm-1 ( (amide)). The diameter of Gd2O3@PEGdiCOOH600-Amylovis®NPs and Gd2O3@PEGdiCOOH1200-Amylovis®NPs (TEM: 2 and 6 nm; DLS: 156 and 128 nm, respectively) and the relaxivity values (r1= 1,6 and 5,8 mM-1s-1, respectively) allow to assure their potential use as contrast agent.

The use of nanomaterials rationally engineered to treat cancer is a burgeoning field that has reported great medical achievements. Iron-based polymeric nano-formulations with precisely tuned physicochemical properties are an expanding and versatile therapeutic strategy for tumor treatment. Recently, a peculiar type of regulated necrosis named ferroptosis has gained increased attention as a target for cancer therapy. Here, we show for the first time that novel iron oxide nanoparticles coated with gallic acid and polyacrylic acid (IONP–GA/PAA) possess intrinsic cytotoxic activity on various cancer cell lines. Indeed, IONP–GA/PAA treatment efficiently induces ferroptosis in glioblastoma, neuroblastoma, and fibrosarcoma cells. IONP–GA/PAA-induced ferroptosis was blocked by the canonical ferroptosis inhibitors, including deferoxamine and ciclopirox olamine (iron chelators), and ferrostatin-1, the lipophilic radical trap. These ferroptosis inhibitors also prevented the lipid hydroperoxide generation promoted by the nanoparticles. Altogether, we report on novel ferroptosis-inducing iron encapsulated nanoparticles with potent anti-cancer properties, which has promising potential for further in vivo validation.

Solid-state Pb2+-ion selective electrodes (Pb2+-ISEs) based on liquid membranes using three 1-aroyl-3,3-dimethylthioureas as ionophores were developed. The receptors differ structurally in the aromatic ring of the 1-aroyl group and have been labeled as FDM, BDM, and TDM. The analytical performance of the constructed electrodes was studied by determining the calibration parameters. The electrodes showed Nernstian behavior with average sensitivities of 30.1, 31.5 and 26.6 mV/dec, as well as average lifetimes of 100, 60 and 7 days, respectively. Cd2+ and Cu2+ cations were interfering toward Pb2+ ions detection. The sensing membranes were studied by SEM-EDS and the results have suggested the formation of aggregates through time related to complex species Pb2+-aroylthioureas. Additionally, quantum chemical calculations were carried out at the B3LYP/6-311G(d,p) level of theory to compute the geometry, frontier molecular orbital energies and global reactivity parameters of the aroylthioureas in tributyl phosphate (TBP) as solvent mediator. Correlation studies between the receptor's quantum chemical parameters and the experimental analytical response of the Pb2+-ISEs were addressed in order to clarify the differences observed in the analytical response of the constructed electrodes. The results support the chemical model of interaction between thioureas and Pb2+ ions through orbital control involving vacant d-orbitals of the metal ion and electrons from the HOMO of the organic molecule.

Specific contrast agents facilitate the use of Magnetic Resonance Imaging (MRI) in the early diagnosis of Alzheimer's disease (AD). In the present work, a procedure for the synthesis of a potential MRI contrast agent based on PEGylated Gd2O3 particles is developed for conjugation to Amylovis®, a family of compounds that has shown a high affinity for the pathological structures present in AD. The products obtained were characterized by FT-IR, ICP, TGA, DLS and SEM. Amylovis-functionalized Gd2O3 particles showed a spherical morphology, with an average hydrodynamic diameter of 2.5 μm. These particles presented an adequate value of the ratio between the longitudinal (r1) and transversal (r2) relaxivities (r2/r1 = 2.4). This suggests that once these particles have a hydrodynamic diameter smaller than 200 nm, they could be used as a potential contrast agent for MRI.

Thiourea derivatives have been used as receptors in the development of selective electrodes to metallic ions (ISEs). Among the receptors used in the construction of ISEs to Pb(II) ions are: 1benzoyl-3,3-dimethylthiourea (1), 1-(2-furoyl)-3,3-dimethylthiourea (2) and 1-(2-thiophenyl)3,3-dimethylthiourea (3). Although, there are several analytical studies on the performance of those sensors, the development of theoretical models is important to elucidate the differences observed in their response. In this work, the density functional B3LYP and the 6-311G (d, p) basis set was used to calculate the geometry, the electronic structure, the IR spectra, the energies of the HOMO-LUMO orbitals and the global reactivity parameters of these molecules. The calculated parameters were related with those of the analytical response characteristics for the constructed sensors. A good correspondence between theoretical and experimental parameters was found and could be established the order of reactivity: (3)> (1) ≈ (2) for the studied receptors.

The coordination of photosensitizing dyes to zinc oxide nanoparticles (ZnO NPs) has attracted extensive attention as promising candidates for applications in solar cells. Here, we report the synthesis of ZnO NPs functionalized with geometric isomers of ruthenium(II)-polypyridyl complexes and a preliminary study of their photophysical properties by fluorescence spectroscopy. ZnO NPs synthesis was carried out by direct precipitation. IR, UV-Vis spectroscopy, XRD and TG-DTA techniques were used for ZnO NPs characterization. Trans and cis complexes of Ru(II) using 2,2 '-bipyridine and 2,2'-bipyridine-4,4'-dicarboxylic acid as ligands were assembled to ZnO NPs. The presence not only of a band of around 355 nm, but also at 465 nm, in the electronic spectrum indicates the modification of the ZnO surface with the synthesized complexes. The fluorescence behaviour of Ru(II) complexes modified ZnO NPs suggested an electron transfer process through the system. Remarkably, the trans isomer modified system showed better response during the electron transfer. This information could be considered during the design of photoanodes in Dye-Sensitized Solar Cells.

The use of magnetic nanoparticles (MNPs), such as iron oxide nanoparticles (IONPs), in biomedicine is considered to be a valuable alternative to the more traditional materials due to their chemical stability, cost-effectiveness, surface functionalization, and the possibility to selectively attach and transport targeted species to the desired location under a magnetic field. One of the many main applications of MNPs is DNA separation, which enables genetic material manipulation; consequently, MNPs are used in numerous biotechnological methods, such as gene transfection and molecular recognition systems. In addition, the interaction between the surfaces of MNPs and DNA molecules and the magnetic nature of the resulting composite have facilitated the development of safe and effective gene delivery vectors to treat significant diseases, such as cancer and neurological disorders. Furthermore, the special recognition properties of nucleic acids based on the binding capacity of DNA and the magnetic behavior of the nanoparticles allowing magnetic separation and concentration of analytes have led to the development of biosensors and diagnostic assays; however, both of these applications face important challenges in terms of the improvement of selective nanocarriers and biosensing capacity. In this review, we discuss some aspects of the properties and surface functionalization of MNPs, the interactions between DNA and IONPs, the preparation of DNA nanoplatforms and their biotechnological applications, such as the magnetic separation of DNA, magnetofection, preparation of DNA vaccines, and molecular recognition tools.

The use of magnetic nanoparticles (MNPs), such as iron oxide nanoparticles (IONPs), in biomedicine is considered to be a valuable alternative to the more traditional materials due to their chemical stability, cost-effectiveness, surface functionalization, and the possibility to selectively attach and transport targeted species to the desired location under a magnetic field. One of the many main applications of MNPs is DNA separation, which enables genetic material manipulation; consequently, MNPs are used in numerous biotechnological methods, such as gene transfection and molecular recognition systems. In addition, the interaction between the surfaces of MNPs and DNA molecules and the magnetic nature of the resulting composite have facilitated the development of safe and effective gene delivery vectors to treat significant diseases, such as cancer and neurological disorders. Furthermore, the special recognition properties of nucleic acids based on the binding capacity of DNA and the magnetic behavior of the nanoparticles allowing magnetic separation and concentration of analytes have led to the development of biosensors and diagnostic assays; however, both of these applications face important challenges in terms of the improvement of selective nanocarriers and biosensing capacity. In this review, we discuss some aspects of the properties and surface functionalization of MNPs, the interactions between DNA and IONPs, the preparation of DNA nanoplatforms and their biotechnological applications, such as the magnetic separation of DNA, magnetofection, preparation of DNA vaccines, and molecular recognition tools.

Gold and silver nanoparticles were synthesized via mild alkoxide reduction of Ag+ and AuCl4- in water, under alkaline conditions. Three non-toxic polyols (glycerin, beta-cyclodextrin (beta CD), and a polymer (of beta-cyclodextrin)) were employed in each case as reducing and capping agent. TEM analysis revealed larger nanoparticles when glycerin was used, followed by beta-cyclodextrin, and finally by the polymer. Different numbers of population maxima in nanoparticles size distribution from one alkoxide to another were observed and such variation was dependent on alkoxide's structure complexity. In UV-Vis spectra the typical bands for gold and silver nano-particles were detected. zeta-potential measurements showed more electrostatically stable capping layer for glycerin and beta CD. For the polymer, the stability of the layer should be a result of bulk effects. On the other hand, Ag-Au bi-metallic nanoparticles with core-shell structure were obtained using glycerin and beta-cyclodextrin, whereas a mixture of gold and silver nanoparticles was the result with the polymer. The latter was corroborated via TEM images, EDX, UV-Vis, -potential, and DLS measurements. A systematic study was carried out to elucidate the influence of the different alkoxide molecules on the properties of the resulting nanoparticles.

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