Ceria-Zirconia nanoparticles reduce intracellular globotriaosylceramide accumulation and attenuate kidney injury by enhancing the autophagy flux in cellular and animal models of Fabry disease.

BACKGROUND: Fabry disease (FD) is a lysosome storage disease (LSD) characterized by significantly reduced intracellular autophagy function. This contributes to the progression of intracellular pathologic signaling and can lead to organ injury. Phospholipid-polyethyleneglycol-capped Ceria-Zirconia antioxidant nanoparticles (PEG-CZNPs) have been reported to enhance autophagy flux. We analyzed whether they suppress globotriaosylceramide (Gb3) accumulation by enhancing autophagy flux and thereby attenuate kidney injury in both cellular and animal models of FD. RESULTS: Gb3 was significantly increased in cultured human renal proximal tubular epithelial cells (HK-2) and human podocytes following the siRNA silencing of α galactosidase A (α-GLA). PEG-CZNPs effectively reduced the intracellular accumulation of Gb3 in both cell models of FD and improved both intracellular inflammation and apoptosis in the HK-2 cell model of FD. Moreover these particles attenuated pro fibrotic cytokines in the human podocyte model of FD. This effect was revealed through an improvement of the intracellular autophagy flux function and a reduction in reactive oxygen species (ROS). An FD animal model was generated in which 4-week-old male B6;129-Glatm1Kul/J mice were treated for 8 weeks with 10 mg/kg of PEG-CZNPs (twice weekly via intraperitoneal injection). Gb3 levels were reduced in the kidney tissues of these animals, and their podocyte characteristics and autophagy flux functions were preserved. CONCLUSIONS: PEG-CZNPs alleviate FD associated kidney injury by enhancing autophagy function and thus provide a foundation for the development of new drugs to treat of storage disease.

Green antimicrobial adsorbent containing grafted xanthan gum/SiO2 nanocomposites for malachite green dye.

Recently, removal of synthetic dyes, especially cationic dye of malachite green (MG), and inhibition of the growth of pathogenic microorganism from drinking water have gained much interest due to their high toxic potency for aquatic biosystems. Herein, a new dye adsorbent with outstanding antibacterial activity was fabricated based on xanthan gum (XG) and SiO2 nanoparticles through ultrasonication followed by the crosslinking polymerization with vinyl imidazole monomer. The nano adsorbents were characterized with various techniques such as FTIR, XRD, SEM, EDX, and TEM. The nanocomposites were applied as a filter for discarding MG dye and killing the growth of bacterial strains such as E.coli and S.aureus which are considered as the common impurities for drinking water. The data revealed that a maximum adsorption capacity was recorded as 99.5% (Qmax = 588.2 mg/g) at optimum conditions including 10 mg nanocomposite, 10 mL of MG dye (450 ppm), pH = 7, the temperature of 30 °C, and the adsorption time was adjusted within 6 h. The process of dye adsorption was applied to the common isotherm models of Langmuir, Temkin, and Freundlich, and the findings showed that the adsorption behavior was well fitted with the Langmuir one (R2 = 0.9983). Moreover, different adsorption kinetic models such as pseudo-first order, pseudo-second order, and intra-particle diffusion were studied for understanding the mechanism of MG adsorption onto nanocomposite surface. It was found that both intraparticle diffusion and pseudo-first-order have participated evenly in the adsorption mechanism of MG dye. Ultimately, the as-prepared nanocomposites were tested against the growth of S. aureus, and E.coli manifesting a superior inhibition diameter as 23.5 ± 0.50, and 25.33 ± 0.47 mm against E.coli, and S. aureus, respectively. Therefore, our new XG-g-PVI/SiO2 adsorbent is a very promising adsorbent for the fast and efficient capture of dyes from aqueous solutions.

Innovative bactericidal adsorbents containing modified xanthan gum/montmorillonite nanocomposites for wastewater treatment.

Herein, we reported the preparation of novel antibacterial nanocomposites based on biodegradable polymers. The nanocomposites were applied as capable adsorbent for removing of malachite green (MG) dye, as well as inhibiting of E. coli and S. aureus growth as the most common pollutants for water. The grafted xanthan gum with poly(vinylimidazole) (XG-g-PVI) nanocomposites were synthesized in the presence of different Montmorillonite (MMT) nanoclays concentrations (1%, 3% and 5%). The prepared modified XG nanocomposites were detected through XRD, SEM-EDX, FTIR and TEM. The maximum adsorption MG capacity was determined as 99.99% (909.1 mg/g) in basic medium at 30 °C for 90 min. The adsorption isotherm for removal of MG dye was studied against different models like Langmuir, Freundlich, Temkin, FloryHuggins isotherm models, however, the adsorption results were good fitted with Langmuir isotherm model (R2 = 0.9942). Additionally, various adsorption kinetic models: pseudo-first order, second order, pseudo-second order, and intra-particle diffusion models were studied for adsorption mechanism of MG dye on top of prepared nanocomposite surface. Finally, the antibacterial activity outcomes displayed that the prepared XG-g-PVI/MMT nanocomposites had excellent inhibition growth for bacteria and the antibacterial activity increased abruptly with the increased of MMT nanoclay concentrations.

N-methylene phosphonic acid chitosan/graphene sheets decorated with silver nanoparticles as green antimicrobial agents.

A green and scalable approach for the preparation of few-layered graphene utilizing the biowaste of potato peels has been developed. The potato peels have been dried and carbonized to obtain a new graphite structure that has been exfoliated in N-methylene phosphonic acid chitosan (MPC). The exfoliation process assisted the formation of graphene sheets with a high size diameter and quality of 50% based on the weight of graphite structure. The graphene sheets were green decorated with silver nanoparticles using microwave power to obtain new nanocomposites. The mass ratio between the graphite and silver nitrate was optimized and observed to change the morphology and size diameter of silver nanoparticles. The as-prepared MPC structure, graphene, and silver decorated graphene nanocomposites were characterized using 1HNMR, FTIR, XRD, UV/Vis spectrophotometer, SEM, and TEM besides tested as antimicrobial agents. The bacterial performance was also controlled by changing the number of AgNPs distributed on graphene sheets based on the mass ratios of graphite/AgNO3. The inhibition diameter of silver decorated graphene was considerably increased to 24.8, and 20.1 mm as in the case of MPC-GRP-Ag30 composite compared to the pure graphene (11.2, 13.5 mm) for E. coli and S. aureus, consecutively proposing that the blade edge of graphene sheets can destroy the bacteria membrane and release silver cations promptly that are directed for the interaction with the cytoplasmic parts of the bacteria cell. Such findings offer green and biocompatible antibacterial agents based on the graphene derived from the biowaste products.

Ceria-Zirconia Antioxidant Nanoparticles Attenuate Hypoxia-Induced Acute Kidney Injury by Restoring Autophagy Flux and Alleviating Mitochondrial Damage.

Oxidative stress is one of the principal causes of hypoxia-induced kidney injury. The ceria nanoparticle (CNP) is known to exhibit free radical scavenger and catalytic activities. When zirconia is attached to CNPs (CZNPs), the ceria atom tends to remain in a Ce3+ form and its efficacy as a free radical scavenger thus increases. We determined the effectiveness of CNP and CZNP antioxidant activities against hypoxia-induced acute kidney injury (AKI) and observed that these nanoparticles suppress the apoptosis of hypoxic HK-2 cells by restoring autophagy flux and alleviating mitochondrial damage. In vivo experiments revealed that CZNPs effectively attenuate hypoxia-induced AKI by preserving renal structures and glomerulus function. These nanoparticles can successfully diffuse into HK-2 cells and effectively counteract reactive oxygen species (ROS) to block hypoxia-induced AKI. This suggests that these particles represent a novel approach to controlling this condition.

Development of an Electrogenerated Chemiluminescence Biosensor using Carboxylic acid-functionalized MWCNT and Au Nanoparticles.

A COOH-F-MWCNT-Nafion-Ru(bpy)(3) (2+)-Au-ADH electrogenerated chemiluminescence (ECL) electrode using COOH-functionalized MWCNT (COOH-F-MWCNT) and Au nanoparticles synthesized by the radiation method was fabricated for ethanol sensing. A higher sensing efficiency for ethanol for the ECL biosensor prepared by PAAc-g-MWCNT was measured compared to that of the ECL biosensor prepared by PMAc-g-MWCNT, and purified MWCNT. Experimental parameters affecting ethanol detection were also examined in terms of pH and the content of PAAc-g-MWCNT in Nafion. Little interference of other compounds was observed for the assay of ethanol. Results suggest this ECL biosensor could be applied for ethanol detection in real samples.

Fluorescence enhancement of ruthenium complex on silver using different chain length carboxylic acid terminated thiols: distance and metal concentration study.

The fluorescence enhancement of ruthenium complex (Ru(bpy)3(2+)) was studied on silver surface deposited by simple Tollens mirror reaction. The plasmon effects on spacer distance, silver concentration, and deposition methods were examined. Silver nanoparticles prepared were coated with different chain length carboxylic acid-terminated thiols as spacers. This leads to development of distance between Ag and Ru dye being varied from 4 to 23 A. Effect of different silver deposition methods on the emission spectra was also studied using metal evaporator deposition method. The results show that Ag concentration, Ag film roughness, and specific distance between metal and dye should be tuned for a maximum increase in fluorescence.

Chemical Synthesis of Sea-Urchin Shaped 3D-MnO2 Nano Structures and Their Application in Supercapacitors.

Sea-urchin shaped α-MnO2 hierarchical nano structures have been synthesized by facile thermal method without using any hard or soft template under the mild conditions. The structural and morphology of the 3D-MnO2 was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). From the XRD analysis indicates that MnO2 present in the α form. Morphology analysis shows that α-MnO2 sea-urchins are made by stacked nanorods, the diameter and length of the stacked nanorods present in the range of 50-120 nm and 200-400 nm respectively. The electrochemical behaviour of α-MnO2 has been investigated by cyclic voltammetry (CV) and charge-discharge (CD). The specific capacitance, energy density and power density are 212.0 F g(-1), 21.2 Wh kg(-1) and 1200 W kg(-1) respectively at the current density of 2 A g(-1). The retention of the specific capacitance after completion of 1000 charge-discharge cycles is around 97%. The results reveal that the prepared Sea-urchin shaped α-MnO2 has high specific capacitance and exhibit excellent cycle life.

Surface modification of poly(glycolic acid) (PGA) for biomedical applications.

The immobilization of biological ligands (such as biotin and peptides) onto biodegradable polymer surfaces, including poly(glycolic acid) (PGA) sutures, is complicated by the absence of functional groups on the polymer backbone. We demonstrate a method for overcoming this problem, by attaching (+)-biotinyl-3,6,9-trioxaundecanediamine to the surface of PGA sutures, which immobilizes the ligand through an amide bond between amine (ligands) and carboxylic acid groups (surface-hydrolyzed PGA sutures). Fluorescence microscopy was used to verify the attachment of the biotin ligand to the surface of the PGA suture after a complexation with fluorescein-conjugated streptavidin. The strategy can be generalized to surface modifications of other biodegradable aliphatic polyesters, which would improve the properties of the polymers in biomedical applications such as active targeting of drugs based on ligand-attached, polymeric drug delivery systems.

Surface-initiated atom-transfer radical polymerization of 3-O-methacryloyl-1,2:5,6-di- O-isopropylidene-alpha- D-glucofuranoside onto gold surface.

A sugar-containing polymer was grown on gold surface by surface-initiated atom-transfer radical polymerization (SI-ATRP) of methacrylate monomer, 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranoside (MAIpGIc), using 1,4,8,11-tetraaza-1,4,8,11-tetramethylcyclotetradecane (Me(4)Cyclam) as ligand, 2-bromopropionyl moiety attached on the gold surface as initiator, and Copper(I) bromide as catalyst, respectively, in tetrahydrofuran (THF) medium. The resultant sugar film was characterized by polarized infrared external reflectance spectroscopy (PIERS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), ellipsometry, and contact angle goniometry. The IR peaks characteristics of poly(3-O-methacryloyl-alpha,beta-D-glucopyranoside) (PMAGlc), broad O--H stretch at approximately 3400 cm(-1), and C==O ester stretch at approximately 1748 cm(-1) observed in PIERS spectra demonstrate the formation of PMAGlc on the gold surface. The AFM and SEM images show the polymer growth away from the gold surface without visible domain boundaries, and it further confirms the formation of sugar coating. The method described in the article would be beneficial in many areas, such as pathogen detection and biosensors, considering the biological importance of carbohydrate polymers.

Construction of protein-resistant pOEGMA films by helicon plasma-enhanced chemical vapor deposition.

This paper describes the formation of protein-resistant, poly(ethylene glycol) methyl ether methacrylate (pOEGMA) thin films by helicon plasma-enhanced chemical vapor deposition (helicon-PECVD). pOEGMA was successfully grafted onto a silicon substrate, as a model substrate, without any additional surface initiators, by plasma polymerization of OEGMA. The resulting pOEGMA films were characterized by ellipsometry, FT-IR spectroscopy, X-ray photoelectron spectroscopy and contact angle goniometry. To investigate the protein-resistant property of the pOEGMA films, four different proteins, bovine serum albumin, fibrinogen, lysozyme and ribonuclease A, were tested as model proteins for ellipsometric measurements. The ellipsometric thickness change for all the model proteins was less than 3 A, indicating that the formed pOEGMA films are protein-resistant.