Unilateral rNurr1-V5 transgene expression in nigral dopaminergic neurons mitigates bilateral neuropathology and behavioral deficits in parkinsonian rats with α-synucleinopathy

JOURNAL/nrgr/04.03/01300535-202409000-00039/figure1/v/2024-01-16T170235Z/r/image-tiff Parkinsonism by unilateral, intranigral β-sitosterol β-D-glucoside administration in rats is distinguished in that the α-synuclein insult begins unilaterally but spreads bilaterally and increases in severity over time, thus replicating several clinical features of Parkinson's disease, a typical α-synucleinopathy. As Nurr1 represses α-synuclein, we evaluated whether unilateral transfected of rNurr1-V5 transgene via neurotensin-polyplex to the substantia nigra on day 30 after unilateral β-sitosterol β-D-glucoside lesion could affect bilateral neuropathology and sensorimotor deficits on day 30 post-transfection. This study found that rNurr1-V5 expression but not that of the green fluorescent protein (the negative control) reduced β-sitosterol β-D-glucoside-induced neuropathology. Accordingly, a bilateral increase in tyrosine hydroxylase-positive cells and arborization occurred in the substantia nigra and increased tyrosine hydroxylase-positive ramifications in the striatum. In addition, tyrosine hydroxylase-positive cells displayed less senescence marker β-galactosidase and more neuron-cytoskeleton marker βIII-tubulin and brain-derived neurotrophic factor. A significant decrease in activated microglia (positive to ionized calcium-binding adaptor molecule 1) and neurotoxic astrocytes (positive to glial fibrillary acidic protein and complement component 3) and increased neurotrophic astrocytes (positive to glial fibrillary acidic protein and S100 calcium-binding protein A10) also occurred in the substantia nigra. These effects followed the bilateral reduction in α-synuclein aggregates in the nigrostriatal system, improving sensorimotor behavior. Our results show that unilateral rNurr1-V5 transgene expression in nigral dopaminergic neurons mitigates bilateral neurodegeneration (senescence and loss of neuron-cytoskeleton and tyrosine hydroxylase-positive cells), neuroinflammation (activated microglia, neurotoxic astrocytes), α-synuclein aggregation, and sensorimotor deficits. Increased neurotrophic astrocytes and brain-derived neurotrophic factor can mediate the rNurr1-V5 effect, supporting its potential clinical use in the treatment of Parkinson's disease.

Direct Polyphenol Attachment on the Surfaces of Magnetite Nanoparticles, Using Vitis vinifera, Vaccinium corymbosum, or Punica granatum

This study presents an alternative approach to directly synthesizing magnetite nanoparticles (MNPs) in the presence of Vitis vinifera, Vaccinium corymbosum, and Punica granatum derived from natural sources (grapes, blueberries, and pomegranates, respectively). A modified co-precipitation method that combines phytochemical techniques was developed to produce semispherical MNPs that range in size from 7.7 to 8.8 nm and are coated with a ~1.5 nm thick layer of polyphenols. The observed structure, composition, and surface properties of the MNPs@polyphenols demonstrated the dual functionality of the phenolic groups as both reducing agents and capping molecules that are bonding with Fe ions on the surfaces of the MNPs via -OH groups. Magnetic force microscopy images revealed the uniaxial orientation of single magnetic domains (SMDs) associated with the inverse spinel structure of the magnetite (Fe3O4). The samples' inductive heating (H0 = 28.9 kA/m, f = 764 kHz), measured via the specific loss power (SLP) of the samples, yielded values of up to 187.2 W/g and showed the influence of the average particle size. A cell viability assessment was conducted via the MTT and NRu tests to estimate the metabolic and lysosomal activities of the MNPs@polyphenols in K562 (chronic myelogenous leukemia, ATCC) cells.

Processing and Physicochemical Properties of Magnetite Nanoparticles Coated with Curcuma longa L. Extract

In this work, Curcuma longa L. extract has been used in the synthesis and direct coating of magnetite (Fe₃O₄) nanoparticles ~12 nm, providing a surface layer of polyphenol groups (-OH and -COOH). This contributes to the development of nanocarriers and triggers different bio-applications. Curcuma longa L. is part of the ginger family (Zingiberaceae); the extracts of this plant contain a polyphenol structure compound, and it has an affinity to be linked to Fe ions. The nanoparticles' magnetization obtained corresponded to close hysteresis loop M_s = 8.81 emu/g, coercive field H_c = 26.67 Oe, and low remanence energy as iron oxide superparamagnetic nanoparticles (SPIONs). Furthermore, the synthesized nanoparticles (G-M@T) showed tunable single magnetic domain interactions with uniaxial anisotropy as addressable cores at 90-180°. Surface analysis revealed characteristic peaks of Fe 2p, O 1s, and C 1s. From the last one, it was possible to obtain the C-O, C=O, -OH bonds, achieving an acceptable connection with the HepG2 cell line. The G-M@T nanoparticles do not induce cell toxicity in human peripheral blood mononuclear cells or HepG2 cells in vitro, but they can increase the mitochondrial and lysosomal activity in HepG2 cells, probably related to an apoptotic cell death induction or to a stress response due to the high concentration of iron within the cell.

Cerebral dopamine neurotrophic factor transfection in dopamine neurons using neurotensin-polyplex nanoparticles reverses 6-hydroxydopamine-induced nigrostriatal neurodegeneration

Overexpression of neurotrophic factors in nigral dopamine neurons is a promising approach to reverse neurodegeneration of the nigrostriatal dopamine system, a hallmark in Parkinson's disease. The human cerebral dopamine neurotrophic factor (hCDNF) has recently emerged as a strong candidate for Parkinson's disease therapy. This study shows that hCDNF expression in dopamine neurons using the neurotensin-polyplex nanoparticle system reverses 6-hydroxydopamine-induced morphological, biochemical, and behavioral alterations. Three independent electron microscopy techniques showed that the neurotensin-polyplex nanoparticles containing the hCDNF gene, ranging in size from 20 to 150 nm, enabled the expression of a secretable hCDNF in vitro. Their injection in the substantia nigra compacta on day 21 after the 6-hydroxydopamine lesion resulted in detectable hCDNF in dopamine neurons, whose levels remained constant throughout the study in the substantia nigra compacta and striatum. Compared with the lesioned group, tyrosine hydroxylase-positive (TH⁺) nigral cell population and TH⁺ fiber density rose in the substantia nigra compacta and striatum after hCDNF transfection. An increase in βIII-tubulin and growth-associated protein 43 phospho-S41 (GAP43p) followed TH⁺ cell recovery, as well as dopamine and its catabolite levels. Partial reversal (80%) of drug-activated circling behavior and full recovery of spontaneous motor and non-motor behavior were achieved. Brain-derived neurotrophic factor recovery in dopamine neurons that also occurred suggests its participation in the neurotrophic effects. These findings support the potential of nanoparticle-mediated hCDNF gene delivery to develop a disease-modifying treatment against Parkinson's disease. The Institutional Animal Care and Use Committee of Centro de Investigación y de Estudios Avanzados approved our experimental procedures for animal use (authorization No. 162-15) on June 9, 2019.

Nanobiomechanical behavior of Fe3O4@SiO2and Fe3O4@SiO2-NH2nanoparticles over HeLa cells interfaces

In this work, we studied the impact of magnetic nanoparticles (MNPs) interactions with HeLa cells when they are exposed to high frequency alternating magnetic field (AMF). Specifically, we measured the nanobiomechanical properties of cell interfaces by using atomic force microscopy (AFM). Magnetite (Fe₃O₄) MNPs were synthesized by coprecipitation and encapsulated with silica (SiO₂): Fe₃O₄@SiO₂and functionalized with amino groups (-NH₂): Fe₃O₄@SiO₂-NH₂, by sonochemical processing. HeLa cells were incubated with or without MNPs, and then exposed to AMF at 37 °C. A biomechanical analysis was then performed through AFM, providing the Young's modulus and stiffness of the cells. The statistical analysis (p < 0.001) showed that AMF application or MNPs interaction modified the biomechanical behavior of the cell interfaces. Interestingly, the most significant difference was found for HeLa cells incubated with Fe₃O₄@SiO₂-NH₂and exposed to AMF, showing that the local heat of these MNPs modified their elasticity and stiffness.

Magnetic domains orientation in (Fe3O4/γ-Fe2O3) nanoparticles coated by Gadolinium-diethylenetriaminepentaacetic acid (Gd3+-DTPA)

In this work, the magnetic domains (MDs) orientation was evaluated from magnetite/maghemite nanoparticles (Fe3O4/γ-Fe2O3) NPs coated with Gadolinium (Gd3+) chelated with diethylenetriamine pentaacetate acid (Gd–DTPA). The (Fe3O4/γ–Fe2O3) superparamagnetic cores were configured by adding a DTPA organic layer and paramagnetic Gd as (Fe3O4/γ–Fe2O3)@Gd–DTPA NPs. The cores were obtained by coprecipitation and coated with additional modifications to the synthesis with Gd–DTPA. Analysis of properties showed that particles 9–12 nm, with Gd–DTPA layer thickness ∼10 nm increased their magnetisation from 62.72 to 75.82 emu/g. The result showed that the structure, particle size, composition, thickness and interface defects, as well as the anisotropy, play an important role in MDs orientation of (Fe3O4/γ–Fe2O3)@Gd–DTPA NPs. Magnetic force microscopy (MFM) analysis showed an MDs uniaxial orientation of 90° at magnetisation and disorder at zero conditions and demagnetisation. The MDs interactions showed uniaxial anisotropy defined in the direction of the magnetic field. These addressable and rotational features could be considered for potential applications to induce hydrogen proton alignment in water by longitudinal spin-lattice relaxation T 1 and transversal spin-spin relaxation T 2 as a dual contrast agent and as a theranostic trigger.

Biological synthesis of iron nanoparticles using hydrolysates from a waste-based biorefinery

The purpose of this work was to produce iron nanoparticles (Fe-NP) by microbial pathway from anaerobic bacteria grown in anaerobic fluidized bed reactors (AnFBRs) that constitute a new stage of a waste-based biorefinery. Bioparticles from biological fluidized bed reactors from a biorefinery of organic fraction of municipal solid wastes (that produces hydrolysates rich in reducing sugars) were nanodecorated (embedded nanobioparticle or nanodecorated bioparticle, ENBP) by biological reduction of iron salts. Factors "origin of bioparticles" (either from hydrogenogenic or methanogenic fluidized bed reactor) and "type of iron precursor salt" (iron chloride or iron citrate) were explored. SEM and high-resolution transmission electron microscopy (HRTEM) showed amorphous distribution of nanoparticles (NP) on the bioparticles surface, although small structures that are nanoparticle-like could be seen in the SEM micrographs. Some agglomeration of NPs was confirmed by DLS. Average NP size was lower in general for NP in ENBP-M than ENBP-H according to HRTEM. The factors did not have a significant influence on the specific surface area of NPs, which was high and in the range 490 to 650 m² g^-1. Analysis by EDS displayed consistent iron concentration 60-65% iron in nanoparticles present in ENBP-M (bioparticles previously grown in methanogenic bioreactor), whereas the iron concentration in NPs present in ENBP-H (bioparticles previously grown in hydrogenogenic bioreactor) was more variable in a range from 8.5 to 62%, depending on the iron salt. X-ray diffraction patterns showed the typical peaks for magnetite at 35° (3 1 1), 43° (4 0 0), and 62° (4 0 0); moreover, siderite diffraction pattern was found at 26° (0 1 2), 38° (1 1 0), and 42° (1 1 3). Results of infrared analysis of ENBP in our work were congruent with presence of magnetite and occasionally siderite determined by XRD analysis as well as presence of both Fe⁺² and F⁺³ (and selected satellite signal peaks) observed by XPS. Our results on the ENBPs hold promise for water treatment, since iron NPs are commonly used in wastewater technologies that treat a wide variety of pollutants. Finally, the biological production of ENBP coupled to a biorefinery could become an environmentally friendly platform for nanomaterial biosynthesis as well as an additional source of revenues for a waste-based biorefinery.

Growth Mechanism and Properties of Self-Assembled InN Nanocolumns on Al Covered Si(111) Substrates by PA-MBE

Self-assembled InN nanocolumns were grown at low temperatures by plasma-assisted molecular beam epitaxy with a high crystalline quality. The self-assembling procedure was carried out on AlN/Al layers on Si(111) substrates avoiding the masking process. The Al interlayer on the Si(111) substrate prevented the formation of amorphous SiN. We found that the growth mechanism at 400 ∘ C of InN nanocolumns started by a layer-layer (2D) nucleation, followed by the growth of 3D islands. This growth mechanism promoted the nanocolumn formation without strain. The nanocolumnar growth proceeded with cylindrical and conical shapes with heights between 250 and 380 nm. Detailed high-resolution transmission electron microscopy analysis showed that the InN nanocolumns have a hexagonal crystalline structure, free of dislocation and other defects. The analysis of the phonon modes also allowed us to identify the hexagonal structure of the nanocolumns. In addition, the photoluminescence spectrum showed an energy transition of 0.72 eV at 20 K for the InN nanocolumns, confirmed by photoreflectance spectroscopy.

Solution based synthesis of Cu(In,Ga)Se2 microcrystals and thin films

Herein, for the first time, we report the synthesis of quaternary Cu(In,Ga)Se₂ microcrystals (CIGSe MCs) using a facile and economical one-pot heating-up method. The most important parameters such as reaction temperature and time were varied to study their influences on the structural, morphological, compositional and optical properties of the MCs. Based on the results, the formation of CIGSe was initiated from binary β-CuSe and then converted into pure phase CIGSe by gradual incorporation of In³⁺ and Ga³⁺ ions into the β-CuSe crystal lattice. As the reaction time increases, the band gap energy was increased from 1.10 to 1.28 eV, whereas the size of the crystals increased from 0.9 to 3.1 μm. Besides, large-scale synthesis of CIGSe MCs exhibited a high reaction yield of 90%. Furthermore, the CIGSe MCs dispersed in the ethanol was coated as thin films by a drop casting method, which showed the optimum carrier concentration, high mobility and low resistivity. Moreover, the photoconductivity of the CIGSe MC thin film was enhanced by three order magnitude in comparison with CIGSe NC thin films. The solar cells fabricated with CIGSe MCs showed the PCE of 0.59% which is 14.75 times higher than CIGSe NCs. These preliminary results confirmed the potential of CIGSe MCs as an active absorber layer in low-cost thin film solar cells.

Herein, for the first time, we report the synthesis of quaternary Cu(In,Ga)Se₂ microcrystals (CIGSe MCs) using a facile and economical one-pot heating-up method.

Growth and Self-Assembly of Silicon⁻Silicon Carbide Nanoparticles into Hybrid Worm-Like Nanostructures at the Silicon Wafer Surface

This work describes the growth of silicon⁻silicon carbide nanoparticles (Si⁻SiC) and their self-assembly into worm-like 1D hybrid nanostructures at the interface of graphene oxide/silicon wafer (GO/Si) under Ar atmosphere at 1000 °C. Depending on GO film thickness, spread silicon nanoparticles apparently develop on GO layers, or GO-embedded Si⁻SiC nanoparticles self-assembled into some-micrometers-long worm-like nanowires. It was found that the nanoarrays show that carbon⁻silicon-based nanowires (CSNW) are standing on the Si wafer. It was assumed that Si nanoparticles originated from melted Si at the Si wafer surface and GO-induced nucleation. Additionally, a mechanism for the formation of CSNW is proposed.

The mechanochemical synthesis of PbTe nanostructures: following the Ostwald ripening effect during milling

A fundamental understanding of the Ostwald ripening effect (ORE) during the mechanochemical synthesis of PbTe nanostructures is presented. The ripening process involves the coarsening of larger particles from those of smaller size; this phenomenon was systematically evaluated at different stages of milling by microscopy analyses (AFM, TEM, STEM and HRTEM). At the early stage of milling, smaller particles and quantum dots are eventually dissolved to lower the total energy assciated with their surfaces. The ripening process - during milling - involves short-range mass transfer among particles. HRTEM analyses allowed us to identify that coarsening occurs by thermo-mechanically activated cooperative mechanisms. The detachment of the atoms from smaller particles to form bigger ones plays a major role in the particle coarsening. It was found that the coarsening process was not limited to crystalline nanostructures; so grain boundaries, edge dislocations and boundaries among crystalline and amorphous phases also play an important role to determine how species migration contributes to generate coarse particles. Those serve as sites for inducing coarsening in an equivalent way as surfaces do. Secondary ion mass spectrometry and elemental chemical mapping (EDX-STEM) revealed that both the purity and the chemical homogeneity of the PbTe nanostructures are prominent features of this material. Additionally, a direct band gap enhancement (780 nm) compared to bulk PbTe (3859 nm) was detected. It occurred due to the quantum confinement effect, lattice imperfections and even surface properties of the nanostructures. It is important to point out that the whole optical behaviour of the PbTe nanostructures was dependent upon the embedded nanoparticles and quantum dots in the clusters and coarse particles ranging from 15 nm to 35 nm.

Liposomes Loaded with Cisplatin and Magnetic Nanoparticles: Physicochemical Characterization, Pharmacokinetics, and In-Vitro Efficacy

With the aim improving drug delivery, liposomes have been employed as carriers for chemotherapeutics achieving promising results; their co-encapsulation with magnetic nanoparticles is evaluated in this work. The objective of this study was to examine the physicochemical characteristics, the pharmacokinetic behaviour, and the efficacy of pegylated liposomes loaded with cisplatin and magnetic nanoparticles (magnetite) (Cis-MLs). Cis-MLs were prepared by a modified reverse-phase evaporation method. To characterize their physicochemical properties, an evaluation was made of particle size, ζ-potential, phospholipid and cholesterol concentration, phase transition temperature (T_m), the encapsulation efficiency of cisplatin and magnetite, and drug release profiles. Additionally, pharmacokinetic studies were conducted on normal Wistar rats, while apoptosis and the cytotoxic effect were assessed with HeLa cells. We present a method for simultaneously encapsulating cisplatin at the core and also embedding magnetite nanoparticles on the membrane of liposomes with a mean vesicular size of 104.4 ± 11.5 nm and a ζ-potential of −40.5 ± 0.8 mV, affording a stable formulation with a safe pharmacokinetic profile. These liposomes elicited a significant effect on cell viability and triggered apoptosis in HeLa cells.

Magnetic domain interactions of Fe3O4 nanoparticles embedded in a SiO2 matrix

Currently, superparamagnetic functionalized systems of magnetite (Fe₃O₄) nanoparticles (NPs) are promising options for applications in hyperthermia therapy, drug delivery and diagnosis. Fe₃O₄ NPs below 20 nm have stable single domains (SSD), which can be oriented by magnetic field application. Dispersion of Fe₃O₄ NPs in silicon dioxide (SiO₂) matrix allows local SSD response with uniaxial anisotropy and orientation to easy axis, 90° <001> or 180° <111>. A successful, easy methodology to produce Fe₃O₄ NPs (6-17 nm) has been used with the Stöber modification. NPs were embedded in amorphous and biocompatible SiO₂ matrix by mechanical stirring in citrate and tetraethyl orthosilicate (TEOS). Fe₃O₄ NPs dispersion was sampled in the range of 2-12 h to observe the SiO₂ matrix formation as time function. TEM characterization identified optimal conditions at 4 h stirring for separation of SSD Fe₃O₄ in SiO₂ matrix. Low magnetization (M_s) of 0.001 emu and a coercivity (H_c) of 24.75 Oe indicate that the embedded SSD Fe₃O₄ in amorphous SiO₂ reduces the M_s by a diamagnetic barrier. Magnetic force microscopy (MFM) showed SSD Fe₃O₄ of 1.2 nm on average embedded in SiO₂ matrix with uniaxial anisotropy response according to Fe³⁺ and Fe²⁺ electron spin coupling and rotation by intrinsic Neél contribution.

Development of a Parenteral Formulation of NTS-Polyplex Nanoparticles for Clinical Purpose

Neurotensin (NTS)-polyplex is a nanoparticle system for targeted gene delivery that holds great promise for treatment of Parkinson’s disease and various types of cancer. However, the high instability in aqueous suspension of NTS-polyplex nanoparticles is a major limitation for their widespread clinical use. To overcome this obstacle, we developed a clinical formulation and a lyophilization process for NTS-polyplex nanoparticles. The reconstituted samples were compared with fresh preparations by using transmission electron microscopy, dynamic light scattering, electrophoretic mobility, circular dichroism and transfection assays in vitro and in vivo. Our formulation was able to confer lyoprotection and stability to these nanoparticles. In addition, transmission electron microscopy (TEM) and size exclusion-high performance liquid chromatography (SEC-HPLC) using a radioactive tag revealed that the interaction of reconstituted nanoparticles with fetal bovine or human serum did not alter their biophysical features. Furthermore, the formulation and the lyophilization procedure guaranteed functional NTS-polyplex nanoparticles for at least six months of storage at 25 °C and 60% relative humidity. Our results offer a pharmaceutical guide for formulation and long-term storage of NTS-polyplex nanoparticles that could be applied to other polyplexes.

A Novel Gas Sensor Based on MgSb2O6 Nanorods to Indicate Variations in Carbon Monoxide and Propane Concentrations

Bystromite (MgSb₂O₆) nanorods were prepared using a colloidal method in the presence of ethylenediamine, after a calcination step at 800 °C in static air. From X-ray powder diffraction analyses, a trirutile-type structure with lattice parameters a = 4.64 Å and c = 9.25 Å and space group P4₂/mnm was identified. Using scanning electron microscopy (SEM), microrods with sizes from 0.2 to 1.6 μm were observed. Transmission electron microscopy (TEM) analyses revealed that the nanorods had a length of ~86 nm and a diameter ~23.8 nm. The gas-sensing properties of these nanostructures were tested using pellets elaborated with powders of the MgSb₂O₆ oxide (calcined at 800 °C) at temperatures 23, 150, 200, 250 and 300 °C. The pellets were exposed to different concentrations of carbon monoxide (CO) and propane (C₃H₈) at these temperatures. The results showed that the MgSb₂O₆ nanorods possess excellent stability and high sensitivity in these atmospheres.

Synthesis and characterisation of YSZ-Al2O3 nanostructured materials

In this work a co-precipitation route was used to synthesise two yttria-stabilised-zirconia (YSZ) phases with different concentrations of alumina (Al2O3). A tetragonal, with 3 mol% yttria, and a cubic, with 8 mol% yttria, phases were added with alumina in different weight proportions, 90/10, 80/20, 70/30, and 60/40, respectively. After synthesised, products were sintered in a range 800-1100 degrees C for different intervals of time. Compounds were characterised by X-ray diffraction, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Rietveld refinements, using FULPROF-Suite software, were carried out to obtain the cell parameters and structural characterisation of products.