Microplastics are commonly referred to as tiny plastic fragments polluting our environment, although their nanometric forms have also been found in our drinking water supplies and many living systems. Their removal is relevant for preserving our health and sustainability and is being pursued according to many different strategies, including filtration through selective porous materials or agglomeration using flocculant agents. An alternative nanotechnological approach described in this paper deals with the capture and degradation of micro and nanoplastics by enzyme-immobilized magnetic nanoparticles.
View Article and Find Full Text PDFJacobsite is a relatively rare mineral of composition MnFe2O4, found in Urandi (Bahia State) in Brazil. It is also a common species in the deep-sea manganese nodules, attracting the interest of many mineral-extracting companies. Because of its spinel constitution similar to magnetite, Jacobsite is commonly called a manganese-ferrite.
View Article and Find Full Text PDFRSC Adv
June 2024
A supramolecular complex μ--tetra(4-pyridyl) porphyrinate nickel(ii)tetrakis[bis(bipyridine)(chloro)ruthenium(ii)] ([NiTPyP{Ru(bipy)Cl}]) was intercalated into the interlayer space of natural smectite clay (shortened as Ba) collected in a Cameroonian deposit at Bagba hill. Physicochemical characterization of the resulting material using ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) confirmed the intercalation of the porphyrin within the interlayer space of the clay. The intercalated clay was then used to form a stable thin film onto a glassy carbon electrode (GCE) by drop casting a suspension of the hybrid material.
View Article and Find Full Text PDFNanoporous gold electrodes are of great interest in electroanalytical chemistry, because of their unusual activity and large surface area. The electrochemical activity can be further improved by coating with molecular catalysts such as the tetraruthenated cobalt-tetrapyridylporphyrazines investigated in this work. The plasmonic enhancement of the scattered light at the nanoholes and borders modifies the electrode's optical characteristics, improving the transmission through the surface-enhanced Raman scattering (SERS) effect.
View Article and Find Full Text PDFCo-abietate and Cu-abietate complexes were obtained by a low-cost and eco-friendly route. The synthesis process used resin and an aqueous solution of CuSO/CoSO at a mild temperature (80 °C) without organic solvents. The obtained complexes are functional pigments for commercial architectural paints with antipathogenic activity.
View Article and Find Full Text PDFUrease is an enzyme containing a dinuclear nickel active center responsible for the hydrolysis of urea into carbon dioxide and ammonia. Interestingly, inorganic models of urease are unable to mimic its mechanism despite their similarities to the enzyme active site. The reason behind the discrepancy in urea decomposition mechanisms between inorganic models and urease is still unknown.
View Article and Find Full Text PDFThe search for less expensive and viable products is always one of the challenges for research development. Commonly, the synthesis of coordination compounds involves expensive ligands, through expensive and low-yield routes, in addition to generating toxic and unusable residues. In this work, the organic ligand used is derived from the resin of a reforestation tree, Pinus elliottii var.
View Article and Find Full Text PDFInflammasomes are cytosolic complexes composed of a Nod-like receptor, NLR, the adaptor protein, ASC, and a proteolytic enzyme, caspase-1. Inflammasome activation leads to caspase-1 activation and promotes functional maturation of IL-1β and IL-18, two prototypical inflammatory cytokines. Besides, inflammasome activation leads to pyroptosis, an inflammatory type of cell death.
View Article and Find Full Text PDFMolecular machines, as exemplified by the kinesin and microtubule system, are responsible for molecular transport in cells. The monitoring of the cellular machinery has attracted much attention in recent years, requiring sophisticated techniques such as optical tweezers, and dark field hyperspectral and fluorescence microscopies. It also demands suitable procedures for immobilization and labeling with functional agents such as dyes, plasmonic nanoparticles and quantum dots.
View Article and Find Full Text PDFA new supramolecular electrocatalyst for Oxygen Evolution Reaction (OER) was synthesized from a central multibridging cobalt tetrapyridylporphyrazine (CoTPyPz) species by attaching four [Ru(bpy)Cl] groups. Both CoTPyPz and the tetraruthenated cobalt porphyrazine species, TRuCoTPyPz, form very homogenous molecular films just by dropcasting their methanol solutions onto GCE electrodes. Such films exhibited low overpotentials for O evolution, e.
View Article and Find Full Text PDFA ranelate ion, an old antiosteoporotic drug, readily reacts with gold(III) ions generating stable gold nanoparticles (AuNP@Ran). The reaction proceeds rapidly under green conditions and is specific for gold ions at room temperature. Their characteristic color associated with the plasmonic resonance effects allows its use in colorimetric/spectrophotometric analysis, as well as in spot test assays.
View Article and Find Full Text PDFThis data article is associated with the work "Ecofriendly synthesis of Zn-abietate complex derived from resin and its application as an antibacterial pigment against and ". The characterization data of the Zn-abietate complex obtained from resin and their reactional intermediary (Na-abietate) are reported. The Na-abietate was prepared with purified Pinus resin and sodium hydroxide (≥ 99%) in a stoichiometric ratio of 1:1.
View Article and Find Full Text PDFThe analytical determination of lithium ions is usually performed by atomic absorption and X-ray fluorescence methods. Chemical analysis based on polyfluoroporphyrin chromogenic methods is also being employed, especially for biological samples. However, all existing methods are expensive and not suitable for routine work or field assays.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
November 2021
Inspired on the outstanding behavior of the BODIPY dye, a new fluorescent boron fluoride derivative of the classical 2,2'-dihydroxy-1,1'-naphtalazine or YELLOW 101 dye has been synthesized and investigated in this work. Analogously to YELLOW 101 (λ = 510 nm), the new species, here denoted BYELLOW 101, exhibits strong fluorescence around 570 and 535 nm in the solid form and in organic solvents, respectively. The observed red shift of the luminescence emission can be explored in the superparamagnetic fluorescent materials employed in MPI (magnetic particle inspection) technology, decreasing the influence of the FRET mechanism, - a critical limitation in this type of system.
View Article and Find Full Text PDFThe production of materials that contain more than one functional constituent, the so-called multifunctional materials, is quite relevant in advanced technology. By acting as building blocks, nanoparticles can be suitably explored for generating higher-order multifunctional structures. In this regard, herein, a special clustered magneto-fluorescent superstructure has been developed for non-destructive detection of flaws and shallow subsurface discontinuities in industrial ferromagnetic materials.
View Article and Find Full Text PDFThe time scale for interfacial photoinduced electron transfer (PeT) in plasmonic nanoparticles is not well established and the details are still under debate. This has renewed the interest in studying the electron transfer effect from both experimental and theoretical points of view. We present a quantitative analysis of PeT in single spherical gold (Au) and gold@palladium core@shell (Au@Pd) nanoparticles supported on reduced graphene oxide (RGO) using dark-field hyperspectral microscopy (DFHM) and electrochemical impedance spectroscopy (EIS).
View Article and Find Full Text PDFPentacyanidoferrate(II) complexes of aromatic N-heterocycles, such as 4-cyanopyridine, exhibit characteristic colors and strong metallochromism associated with the donor-acceptor interactions of the metal ions with the cyanide ligands. In the presence of transition metal ions insoluble polymeric complexes are formed, displaying bright yellow, red, brown and green colors with zinc(II), nickel(II), copper(II) and iron(III) ions, respectively. Such metallochromic response is better observed on filter paper, allowing applications in analytical spot tests.
View Article and Find Full Text PDFMicron
June 2019
Turkevich gold nanoparticles colloidal solutions undergo further changes after ageing for several weeks or months, and in most cases a spongy dark material can be observed suspended in the red solution. CytoViva® dark-field microscopy images and high resolution transmission electron micrographys (HRTEM) of the strange body played a central role and revealed a fibrous structure, consistent with cellulose, as commonly found in the cell-walls of many fungi. Surprisingly, the interior of the fibers are filled with gold nanoparticles, responsible for the high contrasting images obtained in this work.
View Article and Find Full Text PDFSignificant differences were found in the proton-coupled redox chemistry and catalytic behavior of the binuclear [{Ru(H2O)(bpz)}2(tpy2ph)](PF6)4 complex [bpz = 2,2'-bipyrazine; tpy2ph = 1,3-bis(4'-2,2':6',2''-terpyridin-4-yl)benzene] as compared with the structurally analogous derivative with 2,2'-bipyridine (bpy) instead of bpz. The differences were assigned to the stronger π-accepting character of bpz relative to bpy as the ancillary ligand. The expectation of a positive shift for the Ru-centered redox potentials was confirmed for the lower oxidation state species, but that trend was reversed in the formation of the high-valence catalytic active species as shown by a negative shift of 0.
View Article and Find Full Text PDFDrugs bearing metal-coordinating moieties can alter biological metal distribution. In this work, a complex between iron(II) and diflunisal was prepared in the solid state, exhibiting the following composition: [Fe(diflunisal)(HO)], (Fe(dif)). The ability of diflunisal to alter labile pools of both plasmatic and cellular iron was investigated in this work.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
November 2018
The Raman spectral profile of p-methylcarbohydrazonethioamide (MCHT) is completely changed due to strong SERS effects upon bonding onto gold nanoparticles surface, but some vibrational modes are further enhanced in the presence of Hg(II) ions. The lack of SERS response for most common metal ions indicates that the coordinating groups are interacting with the gold nanoparticles surface and not available for binding metal ions in solution, except for mercury ions. The selective enhancement of some vibrational modes is consistent with significant conformational changes upon binding of Hg(II) ion onto the AuNP@MCHT hybrid, as confirmed by TEM/EDS measurements, demonstrating its potentiality as a highly selective and sensitive SERS substrate.
View Article and Find Full Text PDFThe simultaneous electrochemical detection of mood disorder related substances, such as amitriptyline, melatonin and tryptophan, was successfully achieved by using a novel nano-magnetic electrochemical sensor design, encompassing FeO nanoparticles decorated with carbon quantum dots (MagNPs/Cdots). The magnetic composite was characterized using HR-TEM microscopy, XRD and Raman spectroscopy, and was applied onto a glassy carbon electrode using a miniature neodymium magnet. The determination of amitriptyline, melatonin and tryptophan was performed by monitoring oxidation promoted by MagNPs/Cdots in BR-buffer at pH 3.
View Article and Find Full Text PDFAn unusual photooxidation of a coordinated 4-mercaptopyridine ( SpyH) ligand in the [Ru(Hmctpy)(dmbpy)(κ S-SpyH)]complex (Hmctpy = 4'-carboxy-2,2';6',2″-terpyridine, dmbpy = 4,4'-dimethyl-2,2'-bipyridine) takes place under visible and UV irradiation, in aerated acetonitrile. The [Ru(mctpy)(dmbpy)(κ S-SOpy)] sulfinato product has been characterized by a variety of methods, including X-ray diffraction which supports the presence of the Ru-κ S-SpyH isomer in the starting complex. The photooxidation of the 4-mercaptopyridine ligand enhances the back-bonding interactions in the complex by means of the strongly acceptor 4-pyridinesulfinato-SOpy species, increasing the redox potential of the Ru(III)/Ru(II) couple significantly from 1.
View Article and Find Full Text PDFThe kinesin-microtubule pair has attracted much attention in recent years due to their promising use in the development of synthetic nanotransport machines. One of the challenges to study such system is how to observe the motility of either kinesin or microtubule. The usual technique for observation of the molecular machinery pair is by fluorescence microscopy, where fluorescent probes are bound to one, or both species, through a biotin-avidin linker.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
June 2018
The extraction of dysprosium (Dy3+) ions from aqueous solution was carried out successfully, using magnetite (Fe3O4) nanoparticles functionalized with diethylenetriaminepentaacetic acid (MagNP@DTPA). The process was monitored by energy dispersive X-ray fluorescence spectroscopy, as a function of concentration, proceeding according to a Langmuir isotherm with an equilibrium constant of 2.57 × 10-3 g(MagNP) L-1 and a saturation limit of 63.
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