Ruggero Angelico - Academia.edu (original) (raw)
Papers by Ruggero Angelico
Nanomaterials, Oct 24, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Applied sciences, Jul 31, 2017
Due to the wide variation in geographic and climatic conditions, the search for high-performance ... more Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the "weak gel" model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as "mechanical buffer" in the whole explored range of cooling rates.
Applied sciences, Feb 9, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of environmental chemical engineering, Apr 1, 2019
Abstract Magnetite nanoparticles (NPs) were synthetized by partial oxidation of hot Fe(II) sulfat... more Abstract Magnetite nanoparticles (NPs) were synthetized by partial oxidation of hot Fe(II) sulfate aqueous solutions upon addition of variable amounts of alkali/nitrate ions in a N2 atmosphere. The resulting NPs were extensively characterized by Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRPD), Dynamic Light Scattering (DLS) and Brunauer-Emmett-Teller (BET) analysis. Depending on the final pH after synthesis, partially oxidized magnetite NPs were obtained with average crystallite size ranging from 29 to 116 nm. The potential of NPs as arsenic adsorbents was investigated through batch adsorption experiments. The analysis of the adsorption isotherms performed on the basis of both Freundlich and Langmuir models, revealed that arsenic adsorption capacity was more efficient for magnetite NPs synthetized at final pH ≤ 6.56, characterized by polydisperse submicrometric aggregates with coarse macro- and mesopore distributions.
Journal of Plant Nutrition and Soil Science, 2019
In soil, iron (Fe) solubility depends on complex interactions between Fe minerals and organic mat... more In soil, iron (Fe) solubility depends on complex interactions between Fe minerals and organic matter, but very little is known about plant availability of Fe present in Fe oxides associated with humic substances. For this purpose, this study investigates the effect of Fe mineral crystallinity in the presence of humic acids (HA) on Fe availability to plants. Four Fe–HA mineral coprecipitates were prepared, either in the presence or absence of oxygen, i.e., two goethite (G)‐HA samples containing large amounts of Fe as nanocrystalline goethite and ferrihydrite mixed phases, and two magnetite (M)‐HA samples containing crystalline magnetite. Bioavailability studies were conducted in hydroponic systems on cucumber plants (Cucumis sativus L.) grown under Fe deficient conditions and supplied with the Fe–HA coprecipitates containing goethite or magnetite. Results showed that plants grown in the presence of Fe–HA coprecipitates exhibited a complete recovery from Fe deficiency, albeit less eff...
Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk ... more Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, is gaining an increasingly widespread clinical consensus as a natural remedy in the treatment of numerous chronic liver diseases such as cirrhosis and hepatocellular carcinoma due to its antioxidant, anti-inflammatory, anticancer and antiviral activities. Silymarin is able also to increase the stability of cell membrane, is active in the regeneration of tissues and prevents cardiac diseases through numerous mechanisms that include the action of chelating promoters of metals and scavenging free radicals. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 μg/mL) and low bioavailability. Furthermore, despite its poor solubility in water, silymarin does not retain lipophilic properties and this leads to poor intestinal permeability and rapid excretion in bile and urine. To potentiate the therapeutic action and promote sustained release of silymarin, numerous strategies have been proposed to tackle the low solubility in water and provide a prolonged drug release at the site of absorption. The purpose of this study is to review the different types of microand nanocarriers available in literature as delivery strategies to improve the intestinal absorption and bioavailability of silymarin.
Molecules, Jun 7, 2019
Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk ... more Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, has anti-oxidant, anti-inflammatory, anti-cancer and anti-viral activities potentially useful in the treatment of several liver disorders, such as chronic liver diseases, cirrhosis and hepatocellular carcinoma. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 µg/mL), low bioavailability and poor intestinal absorption. To improve its bioavailability and provide a prolonged silymarin release at the site of absorption, the use of nanotechnological strategies appears to be a promising method to potentiate the therapeutic action and promote sustained release of the active herbal extract. The purpose of this study is to review the different nanostructured systems available in literature as delivery strategies to improve the absorption and bioavailability of silymarin.
International Journal of Molecular Sciences
Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia in t... more Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia in the elderly population. Since its original description, there has been intense debate regarding the factors that trigger its pathology. It is becoming apparent that AD is more than a brain disease and harms the whole-body metabolism. We analyzed 630 polar and apolar metabolites in the blood of 20 patients with AD and 20 healthy individuals, to determine whether the composition of plasma metabolites could offer additional indicators to evaluate any alterations in the metabolic pathways related to the illness. Multivariate statistical analysis showed that there were at least 25 significantly dysregulated metabolites in patients with AD compared with the controls. Two membrane lipid components, glycerophospholipids and ceramide, were upregulated, whereas glutamic acid, other phospholipids, and sphingolipids were downregulated. The data were analyzed using metabolite set enrichment analysis a...
Nano-Structures and Nano-Objects, Aug 1, 2015
The synthesis, morphological characterization, and colloidal properties of Hematite nanoparticles... more The synthesis, morphological characterization, and colloidal properties of Hematite nanoparticles (hemNP) with different sizes and shapes were presented. To prepare hemNP we used hydrothermal synthesis with different combinations of reaction conditions. Various characterization techniques involving XRD, TEM, AFM and DLS were employed to describe the dependence of the hemNP size, charge and morphology on different synthesis conditions. Spheroidal Hematite nanoparticles from 20 to 60 nm were obtained by varying the rate of addition of iron precursor solutions and the aging time (Δt) at ca. 100∘C. The transformation from Ferrihydrite to Hematite (α-Fe2O3) started with a burst nucleation of nanosized crystallites, followed by a first-order kinetic growth of primary grains up to a final threshold size of ca 30 nm. Colloidal behavior was also checked at pH 4 and 7, finding interparticle aggregation at circumneutral pH only for hemNP obtained for Δt<2 h. Electrophoretic ζ potential measurements yield positive values at pH 4 and negative at pH 7. The shifts in (IEP) at lower values depended on the adsorption of appreciable counterions on the particle surface and reduced at pH 7 the charge–charge repulsion, whereas the attractive forces became predominant. The results confirmed that the particle size of the Hematite nanoparticle critically affected their colloidal behavior with significant consequences for sorption and aggregation processes. Particularly for low particle sizes of the order of 10–20 nm, the surface charge and surface reactivity also could differ in important ways compared to 40–60 nm size particles.
Journal of Mass Spectrometry, Sep 28, 2012
A novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to... more A novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to the generation of uridine monophosphate (UMP), was evidenced during the alkylation reaction of cytidine monophosphate (CMP) by dodecyl epoxide. Liquid chromatography‐electrospray ionization – ion trap ‐ mass spectrometry was used to separate and identify the reaction products and to follow their formation over time. The detection of hydroxy‐amino‐dodecane, concurrently with free UMP, in the reaction mixture suggested that, among the various alkyl‐derivatives formed, CMP alkylated on the amino group of cytosine could undergo tautomerization to an imine and hydrolytic deamination, generating UMP. Interestingly, no evidence for this peculiar conversion pathway was obtained when guanosine monophosphate (GMP), the complementary ribonucleotide of CMP, was also present in the reaction mixture, due to the fact that NH2‐alkylated CMP was not formed in this case. The last finding emphasized the role played by CMP–GMP molecular interactions, mediated by a micellar environment, in hindering the alkylation reaction at the level of the cytosine amino group. Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Physical Chemistry B, Feb 16, 2002
Physical Review Letters, Sep 28, 1998
Journal of Biomedical Nanotechnology, Apr 1, 2016
Liposomes are nanocarriers able to solubilize and deliver a wide range of hydrophobic pharmaceuti... more Liposomes are nanocarriers able to solubilize and deliver a wide range of hydrophobic pharmaceuticals and to increase drug bioavailability. They show a natural tendency to hepatic accumulation, and thus represent an optimal drug delivery system for the treatment of liver diseases, including chronic virus hepatitis C. Silibinin, the main and more active component of the seed extract from Silybum Marianum, is a hydrophobic flavolignan emerging as an alternative medication for the treatment of hepatitis C virus infection, as it has been shown to inhibit hepatitis C virus entry and replication. In this study we compared cellular delivery and antiviral activity of silibinin encapsulated into phytoliposomes or not, used at the aim to overcome its poor water-solubility and bioavailability. First, it was confirmed the inhibitory activity manifested by lipid-free silibinin in preventing hepatitis C virus entry into the cells. Our data clearly demonstrated that phytoliposomeencapsulated silibinin was absorbed by the cells 2.4 fold more efficiently than the free molecule and showed a three hundreds fold more potent pharmacological activity. Moreover, we surprisingly observed that phytoliposomes themselves inhibited virus entry by reducing the infectivity of viral particles. Based on these observations, phytoliposomes used in this study might be proposed as a delivery system actively contributing to the antiviral efficacy of the encapsulated drug.
Langmuir, Feb 4, 1999
A pulsed field gradient FT 1H NMR study on the system soybean lecithin/water/perdeuterated cycloh... more A pulsed field gradient FT 1H NMR study on the system soybean lecithin/water/perdeuterated cyclohexane, covering a wide range of compositions, is presented. The water diffusion was found to be Gaussian with a well-defined, time-independent, single diffusion ...
Physical Chemistry Chemical Physics, 2004
The microstructure of the quaternary water-in-oil microemulsion CTAB/water/n-pentanol/n-hexane ha... more The microstructure of the quaternary water-in-oil microemulsion CTAB/water/n-pentanol/n-hexane has been investigated by means of the pulsed gradient spin-echo NMR technique over a wide range of composition. The composition of the continuous organic phase and of the interfacial phase has been determined through the analysis of the n-pentanol self-diffusion coefficient. The size of the reverse aggregates has been evaluated from the CTAB self-diffusion coefficient. The correlation of the reverse micellar size with interfacial composition has therefore been possible. Results coming from both water dilution lines and interface dilution lines have been analyzed according to suitable models. A "master plot", i.e., a graphical representation that allows us to display the data collected at all the possible compositions of the four components system, is also proposed.
Langmuir, Aug 30, 2007
Microemulsions have been widely used as microreactors for the synthesis of nanoparticles and meso... more Microemulsions have been widely used as microreactors for the synthesis of nanoparticles and mesoporous materials. The correlation between the microstructure of a microemulsion and the features of the obtained materials is the most intriguing problem. On this point, many investigations have their ground on the structure of the precursor microemulsion, i.e., the system before the reaction takes place. Nevertheless, any reactions usually involve the formation of byproducts (aside from the nanoparticles). Several of these byproducts (e.g., ions, amphiphilic molecules) could modify the microemulsion structure during the course of the reaction. Here we examine the hydrolysis of tetraethoxysilane (TEOS) in the water-in-oil microemulsion hexadecyl-trimethylammonium bromide (CTAB)/pentanol/hexane/water. Conductivity and NMR measurements performed during the course of the reaction, in combination with dynamic light scattering and pulsed field gradient spin-echo NMR investigation performed on the microemulsion upon the addition of ethanol, indicate that a byproduct (ethanol) modifies the microreactor structure. The ethanol produced by the TEOS hydrolysis drives the microemulsion structure from small disconnected reverse micelles toward large connected aggregates until (for high enough ethanol loading) the system phase separates into two coexisting liquid phases (a dense interconnected network and a dilute reverse micellar phase).
Nanomaterials, Oct 24, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Applied sciences, Jul 31, 2017
Due to the wide variation in geographic and climatic conditions, the search for high-performance ... more Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the "weak gel" model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as "mechanical buffer" in the whole explored range of cooling rates.
Applied sciences, Feb 9, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of environmental chemical engineering, Apr 1, 2019
Abstract Magnetite nanoparticles (NPs) were synthetized by partial oxidation of hot Fe(II) sulfat... more Abstract Magnetite nanoparticles (NPs) were synthetized by partial oxidation of hot Fe(II) sulfate aqueous solutions upon addition of variable amounts of alkali/nitrate ions in a N2 atmosphere. The resulting NPs were extensively characterized by Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRPD), Dynamic Light Scattering (DLS) and Brunauer-Emmett-Teller (BET) analysis. Depending on the final pH after synthesis, partially oxidized magnetite NPs were obtained with average crystallite size ranging from 29 to 116 nm. The potential of NPs as arsenic adsorbents was investigated through batch adsorption experiments. The analysis of the adsorption isotherms performed on the basis of both Freundlich and Langmuir models, revealed that arsenic adsorption capacity was more efficient for magnetite NPs synthetized at final pH ≤ 6.56, characterized by polydisperse submicrometric aggregates with coarse macro- and mesopore distributions.
Journal of Plant Nutrition and Soil Science, 2019
In soil, iron (Fe) solubility depends on complex interactions between Fe minerals and organic mat... more In soil, iron (Fe) solubility depends on complex interactions between Fe minerals and organic matter, but very little is known about plant availability of Fe present in Fe oxides associated with humic substances. For this purpose, this study investigates the effect of Fe mineral crystallinity in the presence of humic acids (HA) on Fe availability to plants. Four Fe–HA mineral coprecipitates were prepared, either in the presence or absence of oxygen, i.e., two goethite (G)‐HA samples containing large amounts of Fe as nanocrystalline goethite and ferrihydrite mixed phases, and two magnetite (M)‐HA samples containing crystalline magnetite. Bioavailability studies were conducted in hydroponic systems on cucumber plants (Cucumis sativus L.) grown under Fe deficient conditions and supplied with the Fe–HA coprecipitates containing goethite or magnetite. Results showed that plants grown in the presence of Fe–HA coprecipitates exhibited a complete recovery from Fe deficiency, albeit less eff...
Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk ... more Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, is gaining an increasingly widespread clinical consensus as a natural remedy in the treatment of numerous chronic liver diseases such as cirrhosis and hepatocellular carcinoma due to its antioxidant, anti-inflammatory, anticancer and antiviral activities. Silymarin is able also to increase the stability of cell membrane, is active in the regeneration of tissues and prevents cardiac diseases through numerous mechanisms that include the action of chelating promoters of metals and scavenging free radicals. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 μg/mL) and low bioavailability. Furthermore, despite its poor solubility in water, silymarin does not retain lipophilic properties and this leads to poor intestinal permeability and rapid excretion in bile and urine. To potentiate the therapeutic action and promote sustained release of silymarin, numerous strategies have been proposed to tackle the low solubility in water and provide a prolonged drug release at the site of absorption. The purpose of this study is to review the different types of microand nanocarriers available in literature as delivery strategies to improve the intestinal absorption and bioavailability of silymarin.
Molecules, Jun 7, 2019
Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk ... more Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, has anti-oxidant, anti-inflammatory, anti-cancer and anti-viral activities potentially useful in the treatment of several liver disorders, such as chronic liver diseases, cirrhosis and hepatocellular carcinoma. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 µg/mL), low bioavailability and poor intestinal absorption. To improve its bioavailability and provide a prolonged silymarin release at the site of absorption, the use of nanotechnological strategies appears to be a promising method to potentiate the therapeutic action and promote sustained release of the active herbal extract. The purpose of this study is to review the different nanostructured systems available in literature as delivery strategies to improve the absorption and bioavailability of silymarin.
International Journal of Molecular Sciences
Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia in t... more Alzheimer’s disease (AD), a neurodegenerative disorder, is the most common cause of dementia in the elderly population. Since its original description, there has been intense debate regarding the factors that trigger its pathology. It is becoming apparent that AD is more than a brain disease and harms the whole-body metabolism. We analyzed 630 polar and apolar metabolites in the blood of 20 patients with AD and 20 healthy individuals, to determine whether the composition of plasma metabolites could offer additional indicators to evaluate any alterations in the metabolic pathways related to the illness. Multivariate statistical analysis showed that there were at least 25 significantly dysregulated metabolites in patients with AD compared with the controls. Two membrane lipid components, glycerophospholipids and ceramide, were upregulated, whereas glutamic acid, other phospholipids, and sphingolipids were downregulated. The data were analyzed using metabolite set enrichment analysis a...
Nano-Structures and Nano-Objects, Aug 1, 2015
The synthesis, morphological characterization, and colloidal properties of Hematite nanoparticles... more The synthesis, morphological characterization, and colloidal properties of Hematite nanoparticles (hemNP) with different sizes and shapes were presented. To prepare hemNP we used hydrothermal synthesis with different combinations of reaction conditions. Various characterization techniques involving XRD, TEM, AFM and DLS were employed to describe the dependence of the hemNP size, charge and morphology on different synthesis conditions. Spheroidal Hematite nanoparticles from 20 to 60 nm were obtained by varying the rate of addition of iron precursor solutions and the aging time (Δt) at ca. 100∘C. The transformation from Ferrihydrite to Hematite (α-Fe2O3) started with a burst nucleation of nanosized crystallites, followed by a first-order kinetic growth of primary grains up to a final threshold size of ca 30 nm. Colloidal behavior was also checked at pH 4 and 7, finding interparticle aggregation at circumneutral pH only for hemNP obtained for Δt<2 h. Electrophoretic ζ potential measurements yield positive values at pH 4 and negative at pH 7. The shifts in (IEP) at lower values depended on the adsorption of appreciable counterions on the particle surface and reduced at pH 7 the charge–charge repulsion, whereas the attractive forces became predominant. The results confirmed that the particle size of the Hematite nanoparticle critically affected their colloidal behavior with significant consequences for sorption and aggregation processes. Particularly for low particle sizes of the order of 10–20 nm, the surface charge and surface reactivity also could differ in important ways compared to 40–60 nm size particles.
Journal of Mass Spectrometry, Sep 28, 2012
A novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to... more A novel pathway for cytosine to uracil conversion performed in a micellar environment, leading to the generation of uridine monophosphate (UMP), was evidenced during the alkylation reaction of cytidine monophosphate (CMP) by dodecyl epoxide. Liquid chromatography‐electrospray ionization – ion trap ‐ mass spectrometry was used to separate and identify the reaction products and to follow their formation over time. The detection of hydroxy‐amino‐dodecane, concurrently with free UMP, in the reaction mixture suggested that, among the various alkyl‐derivatives formed, CMP alkylated on the amino group of cytosine could undergo tautomerization to an imine and hydrolytic deamination, generating UMP. Interestingly, no evidence for this peculiar conversion pathway was obtained when guanosine monophosphate (GMP), the complementary ribonucleotide of CMP, was also present in the reaction mixture, due to the fact that NH2‐alkylated CMP was not formed in this case. The last finding emphasized the role played by CMP–GMP molecular interactions, mediated by a micellar environment, in hindering the alkylation reaction at the level of the cytosine amino group. Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Physical Chemistry B, Feb 16, 2002
Physical Review Letters, Sep 28, 1998
Journal of Biomedical Nanotechnology, Apr 1, 2016
Liposomes are nanocarriers able to solubilize and deliver a wide range of hydrophobic pharmaceuti... more Liposomes are nanocarriers able to solubilize and deliver a wide range of hydrophobic pharmaceuticals and to increase drug bioavailability. They show a natural tendency to hepatic accumulation, and thus represent an optimal drug delivery system for the treatment of liver diseases, including chronic virus hepatitis C. Silibinin, the main and more active component of the seed extract from Silybum Marianum, is a hydrophobic flavolignan emerging as an alternative medication for the treatment of hepatitis C virus infection, as it has been shown to inhibit hepatitis C virus entry and replication. In this study we compared cellular delivery and antiviral activity of silibinin encapsulated into phytoliposomes or not, used at the aim to overcome its poor water-solubility and bioavailability. First, it was confirmed the inhibitory activity manifested by lipid-free silibinin in preventing hepatitis C virus entry into the cells. Our data clearly demonstrated that phytoliposomeencapsulated silibinin was absorbed by the cells 2.4 fold more efficiently than the free molecule and showed a three hundreds fold more potent pharmacological activity. Moreover, we surprisingly observed that phytoliposomes themselves inhibited virus entry by reducing the infectivity of viral particles. Based on these observations, phytoliposomes used in this study might be proposed as a delivery system actively contributing to the antiviral efficacy of the encapsulated drug.
Langmuir, Feb 4, 1999
A pulsed field gradient FT 1H NMR study on the system soybean lecithin/water/perdeuterated cycloh... more A pulsed field gradient FT 1H NMR study on the system soybean lecithin/water/perdeuterated cyclohexane, covering a wide range of compositions, is presented. The water diffusion was found to be Gaussian with a well-defined, time-independent, single diffusion ...
Physical Chemistry Chemical Physics, 2004
The microstructure of the quaternary water-in-oil microemulsion CTAB/water/n-pentanol/n-hexane ha... more The microstructure of the quaternary water-in-oil microemulsion CTAB/water/n-pentanol/n-hexane has been investigated by means of the pulsed gradient spin-echo NMR technique over a wide range of composition. The composition of the continuous organic phase and of the interfacial phase has been determined through the analysis of the n-pentanol self-diffusion coefficient. The size of the reverse aggregates has been evaluated from the CTAB self-diffusion coefficient. The correlation of the reverse micellar size with interfacial composition has therefore been possible. Results coming from both water dilution lines and interface dilution lines have been analyzed according to suitable models. A "master plot", i.e., a graphical representation that allows us to display the data collected at all the possible compositions of the four components system, is also proposed.
Langmuir, Aug 30, 2007
Microemulsions have been widely used as microreactors for the synthesis of nanoparticles and meso... more Microemulsions have been widely used as microreactors for the synthesis of nanoparticles and mesoporous materials. The correlation between the microstructure of a microemulsion and the features of the obtained materials is the most intriguing problem. On this point, many investigations have their ground on the structure of the precursor microemulsion, i.e., the system before the reaction takes place. Nevertheless, any reactions usually involve the formation of byproducts (aside from the nanoparticles). Several of these byproducts (e.g., ions, amphiphilic molecules) could modify the microemulsion structure during the course of the reaction. Here we examine the hydrolysis of tetraethoxysilane (TEOS) in the water-in-oil microemulsion hexadecyl-trimethylammonium bromide (CTAB)/pentanol/hexane/water. Conductivity and NMR measurements performed during the course of the reaction, in combination with dynamic light scattering and pulsed field gradient spin-echo NMR investigation performed on the microemulsion upon the addition of ethanol, indicate that a byproduct (ethanol) modifies the microreactor structure. The ethanol produced by the TEOS hydrolysis drives the microemulsion structure from small disconnected reverse micelles toward large connected aggregates until (for high enough ethanol loading) the system phase separates into two coexisting liquid phases (a dense interconnected network and a dilute reverse micellar phase).