Alkaline Water and Longevity: A Murine Study

The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of \u201cdeceleration aging factor\u201d as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models

Enzyme Immobilization on Maghemite Nanoparticles with Improved Catalytic Activity: An Electrochemical Study for Xanthine

Generally, enzyme immobilization on nanoparticles leads to nano-conjugates presenting partially preserved, or even absent, biological properties. Notwithstanding, recent research demonstrated that the coupling to nanomaterials can improve the activity of immobilized enzymes. Herein, xanthine oxidase (XO) was immobilized by self-assembly on peculiar naked iron oxide nanoparticles (surface active maghemite nanoparticles, SAMNs). The catalytic activity of the nanostructured conjugate (SAMN@XO) was assessed by optical spectroscopy and compared to the parent enzyme. SAMN@XO revealed improved catalytic features with respect to the parent enzyme and was applied for the electrochemical studies of xanthine. The present example supports the nascent knowledge concerning protein conjugation to nanoparticle as a means for the modulation of biological activity

Citrinin mycotoxin recognition and removal by naked magnetic nanoparticles

Citrinin is a nephrotoxic mycotoxin which can be synthesized by Monascus mold during the fermentation process in foods. Monascus, generally described as red mold, is a red-pigmented filamentous fungus attracting a great interest for the production of natural dyes and cholesterol-lowering statins. We individuated a specie of Monascus producing high amount of natural dyes. However, this high pigmentation was correlated with the production of citrinin. Peculiar magnetic nanoparticles, synthesized in-house and called \u201cSurface Active Maghemite Nanoparticles\u201d (SAMNs), are proposed as an efficient and reliable mean for citrinin removal from Monascus treated foods. The nanomaterial efficiency for citrinin binding was proved on Monascus suspensions, and SAMN@citrinin complex was characterized by M\u4e7ssbauer spectroscopy and magnetization measurements, showing that SAMNs resulted structurally and magnetically well conserved after citrinin binding. SAMNs are excellent and stable magnetic nano-carrier for toxin removal, which can be applied in food industry

Development of nanoparticle based technologies for food safety

Background Nanoscience and nanotechnology are highly promising and rapidly emerging areas for research and industrial innovation. Due to the remarkable physicochemical properties of manufactured nanomaterials, several promising applications were recently developed in the areas of agriculture and food production. Recently, a new method to synthesize superparamagnetic nanoparticles has been developed. These nanoparticles consist of stoichiometric maghemite, γ-Fe2O3, with unique spectroscopic properties and well-defined crystalline structure, and have been called “surface-active maghemite nanoparticles” (SAMNs). They form stable colloidal suspensions in water without any organic or inorganic coating to prevent their aggregation. At the same time, they are able to specifically and reversibly bind organic molecules, leading to composite colloidal materials, which can be exploited for biotechnological applications. In recent years nanotechnology was combined with various sensing techniques to develop the so-called "nano-sensors". Several promising applications were recently developed in the areas of agriculture and food production, with the capacity to impact both food industry and consumers. These sensors can be an effective alternative to the traditional methods for the detection of toxins and pathogens in food. Electrochemical detection is a popular method involving nanomaterial-based sensors with applications in the food industry. SAMNs show remarkable electrocatalytic properties and were used for the development of electrodes and biosensors. In this thesis, a set of different hybrids that include SAMNs are presented and the electrochemical features of the hybrids are reported. Results Tannic acid (TA), Quaternized Carbon Dots (Q-CD) and hexavalent chromium (CrVI) were successfully immobilized on SAMN surface. SAMN@TA was characterized using electrical impedance spectroscopy, voltammetry and chronoamperometry. The nanostructured ferric tannate interface showed improved conductivity and selective electrocatalytic activity toward the oxidation of polyphenols. A carbon-paste electrode modified with SAMN@TA was used for the determination of polyphenols in blueberry extracts by square-wave voltammetry. Q-CD @SAMN revealed specific electrocatalytic behavior toward the oxidation of phenols and the system was applied to develop a sensor for the coulometric determination of polyphenols from plant extracts. which displayed peculiar electrocatalytic properties attributable to the influence of the strong electrostatic interactions exerted by Q-CDs on the SAMN surface. The sensor is composed of a simple carbon paste electrode in a small volume electrochemical flow cell (1 μL), and is used for the complete direct electro-oxidation of polyphenols from plant extracts. Finally, SAMNs were successfully applied to remove CrVI from water. The hybrid SAMN@CrVI was used to immobilize bovine serum amine oxidase (BSAO) and this complex was electrochemical showed good performances toward H2O2 detection. SAMN@CrVI-BSAO was applied for the development of a polyamine biosensor, which was successfully exploited for the discrimination of tumorous and healthy tissues obtained from liver extracts. Conclusions Sensing strategies based on SAMNs offer unique advantages over other techniques. They are produced by a low-cost procedure, they are physically and chemically stable, biocompatible and environmentally safe. In this thesis, SAMNs were utilized to prepare three different hybrids and were successfully applied for the construction of three different electrochemical sensors, showing good performances, and successfully applied to real samples.La nanoscienza e la nanotecnologia sono aree altamente promettenti e rapidamente emergenti per la ricerca e l'innovazione industriale. A causa delle notevoli proprietà fisico-chimiche dei nanomateriali prodotti, sono state recentemente sviluppate diverse applicazioni promettenti nelle aree dell'agricoltura e della produzione alimentare. Recentemente, è stato sviluppato un nuovo metodo per sintetizzare nanoparticelle superparamagnetiche. Queste nanoparticelle consistono di maghemite stechiometrica, γ-Fe2O3, con proprietà spettroscopiche uniche e struttura cristallina ben definita, e sono state chiamate surface active maghemite nanoparticles (SAMN). Formano sospensioni colloidali stabili in acqua senza alcun rivestimento organico o inorganico per impedire la loro aggregazione. Allo stesso tempo, sono in grado di legare in modo specifico e reversibile molecole organiche, portando a materiali colloidali compositi, che possono essere sfruttati per applicazioni biotecnologiche. Negli ultimi anni la nanotecnologia è stata combinata con varie tecniche di rilevamento per sviluppare i cosiddetti "nano-sensori". Diverse applicazioni promettenti sono state recentemente sviluppate nei settori dell'agricoltura e della produzione alimentare, con la capacità di influenzare sia l'industria alimentare che i consumatori. Questi sensori possono essere un'alternativa efficace ai metodi tradizionali per la rilevazione di tossine e patogeni negli alimenti. Il rilevamento elettrochimico è un metodo popolare che coinvolge sensori basati su nanomateriali con applicazioni nell'industria alimentare. Le SAMN mostrano notevoli proprietà elettrocatalitiche e sono stati utilizzati per lo sviluppo di elettrodi e biosensori. In questa tesi vengono presentati un insieme di diversi ibridi che includono SAMN e vengono riportate le caratteristiche elettrochimiche degli ibridi. Risultati L'acido tannico (TA), quantum dots di carbonio (Q-CD) e il cromo esavalente (CrVI) sono stati immobilizzati con successo sulla superficie del SAMN. SAMN@TA è stato caratterizzato mediante spettroscopia di impedenza elettrica, voltammetria e cronoamperometria. L'interfaccia di tannato ferrico nanostrutturata mostrava conduttività migliorata e attività elettrocatalitica selettiva verso l'ossidazione dei polifenoli. Un elettrodo di pasta di carbone modificato con SAMN@TA è stato utilizzato per la determinazione dei polifenoli negli estratti di mirtillo mediante voltammetria. Q-CD@SAMN ha rivelato un comportamento elettrocatalitico specifico verso l'ossidazione dei fenoli e il sistema è stato applicato per sviluppare un sensore per la determinazione coulometrica dei polifenoli dagli estratti vegetali. che mostrava proprietà elettrocatalitiche peculiari attribuibili all'influenza delle forti interazioni elettrostatiche esercitate dai Q-CD sulla superficie del SAMN. Il sensore è composto da un semplice elettrodo di pasta di carbone in una cella a flusso elettrochimico di piccolo volume (1 μL), ed è utilizzato per l'elettro-ossidazione diretta completa di polifenoli da estratti vegetali. Infine, i SAMN sono stati applicati con successo per rimuovere CrVI dall'acqua. L'ibrido SAMN@CrVI è stato utilizzato per immobilizzare l'ammina ossidasi del siero bovino (BSAO) e questo complesso era elettrochimico ha mostrato buone prestazioni per il rilevamento di H2O2. SAMN@CrVI-BSAO è stato applicato per lo sviluppo di un biosensore in poliammide, che è stato sfruttato con successo per la discriminazione dei tessuti tumorali e sani ottenuti da estratti di fegato. Conclusioni Le strategie di sensing basate sui SAMN offrono vantaggi unici rispetto ad altre tecniche. Sono prodotti con una procedura a basso costo, sono fisicamente e chimicamente stabili, biocompatibili e sicuri per l'ambiente. In questa tesi, i SAMN sono stati utilizzati per preparare tre diversi ibridi e sono stati applicati con successo per la costruzione di tre diversi sensori elettrochimici, mostrando buone prestazioni e applicati con successo a campioni reali

First-Principles Study on the Crystalline Ga4Sb6Te3 Phase Change Compound

The compound on the pseudobinary tie‐line is proposed in the literature as a phase change material with high crystallization temperature. Herein, the crystal structure of this compound is uncovered by means of a genetic algorithm and electronic structure calculations based on density functional theory. As opposed to the parent GaSb compound which crystallizes in the zincblende structure, the compound features an octahedral‐like coordination for Ga as well as for Sb and Te atoms. Other structures close in energy to the ground state are also proposed, including some with a tetrahedral‐like coordination of Ga atoms. Raman spectra computed within density functional perturbation theory and an empirical Bond Polarizability Model are shown to be able to discriminate among the different possible local environments of Ga atoms

The surface reactivity of iron oxide nanoparticles as a potential hazard for aquatic environments: A study on Daphnia magna adults and embryos

Abstract Nano-ecotoxicology is extensively debated and nanomaterial surface reactivity is an emerging topic. Iron oxide nanoparticles are widely applied, with organic or inorganic coatings for stabilizing their suspensions. Surface active maghemite nanoparticles (SAMNs) are the unique example of naked iron oxide displaying high colloidal and structural stability in water and chemical reactivity. The colloidal behavior of SAMNs was studied as a function of the medium salinity and protocols of acute and chronic toxicity on Daphnia magna were consequently adapted. SAMN distribution into the crustacean, intake/depletion rates and swimming performances were evaluated. No sign of toxicity was detected in two model organisms from the first trophic level (P. subcapitata and L. minor). In D. magna, acute EC50 values of SAMN was assessed, while no sub-lethal effects were observed and the accumulation of SAMNs in the gut appeared as the sole cause of mortality. Fast depuration and absence of delayed effects indicated no retention of SAMNs within the organism. In spite of negligible toxicity on D. magna adults, SAMN surface reactivity was responsible of membrane bursting and lethality on embryos. The present study offers a contribution to the nascent knowledge concerning the impact of nanoparticle surface reactivity on biological interfaces

Nanocrystalline Iron Oxides, Composites and Related Materials as a Platform for Electrochemical, Magnetic, and Chemical Biosensors

This review represents a comprehensive attempt to summarize and discuss various sensing applications of iron oxide nanoparticles (NPs), which have attracted a great deal of attention over recent years because of their easy preparation, biocompatibility, nontoxicity, and broad range of biomedical applications. We review the application potential of nanomagnetite based amperometic sensors possessing an intrinsic enzyme mimetic activity similar to that found in natural peroxidases. In addition, we discuss the properties and applications of enzymatic sensors exploiting glucose oxidase, tyrosinase, and other enzymes for sensing a variety of important biomedical species. Among iron oxide-based nanocomposites, we highlight the use of Fe3O4@Au hybrids for designing new electrochemical aptasensors with unique versatility for binding diverse targets, including proteins and peptides. Similarly, sensing applications of composites of iron oxide NPs with graphene derivatives and carbon nanotubes are reviewed. A large part of the review focuses on the development of DNA sensors and iron oxide based immunosensors for the detection of biological and chemical pathogens, contaminants, and other important analytes. Attention is also given to nonelectrochemical sensing, including various types of magnetic, fluorescence, and surface plasmon resonance sensors

A glucose biosensor based on surface active maghemite nanoparticles

A simple carbon paste (CP) electrode, modified with novel maghemite (\uf067-Fe2O3) nanoparticles, called SAMNs (suface active maghemite nanoparticles) and characterized by a mean diameter of about 10 nm, has been developed. The electrode catalyzes the electro-reduction of hydrogen peroxide at low applied potentials (-0.1 V vs. SCE). In order to improve the electrocatalytic properties of the modified electrode an ionic liquid, namely 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6), was introduced. At -0.1 V, the sensitivity of the SAMN-BMIM-PF6-CP electrode was 206.51 nA \ub5M-1cm-2, with a detection limit (S/N = 3) of 0.8 \ub5M, in the 0 \u2013 1.5 mM H2O2 concentration range. Furthermore, glucose oxidase was immobilized on the surface of maghemite nanoparticles as a monomolecular layer, by a bridge constituted of rhodamine B isothiocyanate, leading to a fluorescent, magnetic drivable nanocatalyst, containing 10 \ub1 2 enzyme molecules per nanoparticle. The resulting enzyme electrode presents a linear calibration curve toward glucose in solution in the concentration range of 0 \u2013 1.5 mM glucose, characterized by a sensitivity of 45.85 nA \ub5M-1cm-2 and a detection limit (S/N = 3) of 0.9 \ub5M. The storage stability of the system was evaluated and a half-life of 2 months was calculated, if the electrode is stored at 4\ub0C in buffer. The present work demonstrates the feasibility of these surface active maghemite nanoparticles as efficient hydrogen peroxide electro-catalyst, which can be easily coupled to hydrogen peroxide producing enzymes in order to develop oxidase based reagentless biosensor devices

New Perspectives on Biomedical Applications of Iron Oxide Nanoparticles

Iron oxide nanomaterials are considered promising tools for improved therapeutic efficacy and diagnostic applications in biomedicine. Accordingly, engineered iron oxide nanomaterials are increasingly proposed in biomedicine, and the interdisciplinary researches involving physics, chemistry, biology (nanotechnology) and medicine have led to exciting developments in the last decades. The progresses of the development of magnetic nanoparticles with tailored physico-chemical and surface properties produced a variety of clinically relevant applications, spanning from magnetic resonance imaging (MRI), drug delivery, magnetic hyperthermia, to in vitro diagnostics. Notwithstanding the well-known conventional synthetic procedures and their wide use, recent advances in the synthetic methods open the door to new generations of naked iron oxide nanoparticles possessing peculiar surface chemistries, suitable for other competitive biomedical applications. New abilities to rationally manipulate iron oxides and their physical, chemical, and biological properties, allow the emersion of additional possibilities for designing novel nanomaterials for theranostic applications