ABSTRACT a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investi... more ABSTRACT a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the plasma membrane of Xenopus laevis oocyte. Different protocols of sample preparation to perform an AFM investigation of both external and intracellular sides of the oocyte plasma membrane are presented and discussed. Reproduc-ible AFM images allowed visualization and dimensional characterization of protein complexes differently arranged on both sides of the oocyte plasma membrane. In particular, two different arrangements were visualized: (1) a heterogeneous and irregular distribution of the protein complexes and (2) in some cases a distribution of nanometer-sized membrane domains where protein complexes are densely packed and spatially arranged in an ordered hexagonal motif. In addition, a methodological approach based on the purification of oocyte plasma membrane by ultracentrifugation on sucrose gradient is also described in this work. The potential of AFM as a useful tool for the structural characterization of proteins in a native eukary-otic membrane was established and its relevance for describing the organization of protein complexes in native biological membranes was explored.
Substituted thiophene systems are a class of stable and processable polymers whose electronic pro... more Substituted thiophene systems are a class of stable and processable polymers whose electronic properties can be tailored by monomer functionalization. The more studied are poly(3-alkylthiophenes) (P3AT's) whose basic crystalline organization features have been established by the work, often requiring nonstandard approaches, of many groups. 1-12 There is consensus on a model in which parallel stacks of polyconjugated main chains organize in layers, with the side chains running in the regions between the stacked main chains (Scheme 1a). Fitting the models to diffraction data in various instances required doubling the interlayer lattice periodicity (a in Scheme 1a). 2,7,9 However, disorder, poor regioregularity, and the scarce pro-pensity to crystallization of the rigid polythiophene chain have so far prevented the actual solution and refinement of the crystal structures of these macromolecules. When enantiopure side chains are attached to the thiophene rings, chiral polythiophenes...
a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the ... more a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the plasma membrane of Xenopus laevis oocyte. Different protocols of sample preparation to perform an AFM investigation of both external and intracellular sides of the oocyte plasma membrane are presented and discussed. Reproduc-ible AFM images allowed visualization and dimensional characterization of protein complexes differently arranged on both sides of the oocyte plasma membrane. In particular, two different arrangements were visualized: (1) a heterogeneous and irregular distribution of the protein complexes and (2) in some cases a distribution of nanometer-sized membrane domains where protein complexes are densely packed and spatially arranged in an ordered hexagonal motif. In addition, a methodological approach based on the purification of oocyte plasma membrane by ultracentrifugation on sucrose gradient is also described in this work. The potential of AFM as a useful tool for the stru...
Folate decorated organic nanocarriers loaded with magnetite nanoparticles and paclitaxel provide ... more Folate decorated organic nanocarriers loaded with magnetite nanoparticles and paclitaxel provide a specific and prolonged negative contrast of breast cancers on T2-weighted MR images.
ABSTRACT Zirconia nanoparticles doped with Eu 3+ , Tb 3+ and Gd 3+ ions have been synthesized fol... more ABSTRACT Zirconia nanoparticles doped with Eu 3+ , Tb 3+ and Gd 3+ ions have been synthesized following the benzyl alcohol route. The nano-particles were coated with N-hydroxydodecanamide and encapsu-lated in PLGA-b-PEG-COOH nanomicelles. The magnetic and fluorescent properties of these hybrid nanocarriers were investi-gated, proving them to be potential dual-imaging contrast agents. Increasing interest has been focused on the design of nano-materials suitable for use as non-invasive diagnostic tools for biomedical applications. In particular, the combination of optically active components with a contrast agent (CA) for magnetic resonance imaging (MRI) is an attractive way to develop multifunctional probes for biological imaging and recognition. 1 Although many classes of biocompatible organic–inorganic hybrid materials are potentially useful, many presently available formulations require potentially toxic elements, and indeed, clinical translation of nanotechnology will require nano-particles with the lowest possible likelihood of toxicity. 2 Because of its low toxicity, zirconia (ZrO 2) can be considered a potential host matrix for the design and fabrication of inno-vative nanomaterials. 3 Its doping with lanthanides has been reported and, in particular, Eu 3+ was the most used because of its interesting optical properties. 4 Moreover, Gd-doped zirconia was recently studied with the aim of controlling the phase and morphology of the nanocrystals. 5 A tetrakis-based complex of Tb 3+ ions for the doping of amorphous zirconia nanoparticles has been also reported. 6 The synthesis of lanthanide ion doped (Ln-doped) nanoparticles is a well-established method: several synthetic routes have been reported involving wet chemical synthesis such as the sol–gel process, precipitation and micro-emulsion-based methods followed by annealing at high temperature. 7 Post-synthesis functionalization of metal and metal oxide nanoparticles through coating of their surface with organic molecules allows the achievement of stable colloidal disper-sions. Moreover, surface functionalization procedures are aimed at obtaining compatibility between the inorganic phase and the medium where they are supposed to be applied. One of the most important requirements for nanoparticles to be exploited in medicine as diagnostic and therapeutic agents is to be biocompatible and stable in biological media (e.g., phos-phate buffer saline and serum). These requirements are well fullled by coating the nanoparticle surface with biocompatible and biodegradable polymers, and polyethylene glycol (PEG)-based polymers are the most common choice. 8 Another requirement for nano-therapeutic and diagnostic devices is the possibility to be targeted at specic biological sites. These features are usually achieved with polymers known to be non-toxic, i.e. GRAS (Generally Recognized As Safe) or FDA-approved. 9 As a matter of fact, the most investigated nanosized carrier devices are made up of non-toxic micellar amphiphilic polymers that consist of PEG and a low molecular weight hydrophobic core-forming block such as poly(lactic-co-glycolic)-acid (PLGA) or poly(lactic)acid (PLA). The hydrophobic core serves as a natural carrier environment for the inorganic nanoparticles, being suitable also for the inclusion of lipophilic drugs and/or metallic NPs at the same time. The hydrophilic shell allows the stabilization of the whole hybrid nanostructure in aqueous media. 10 Herein, we report the synthesis and the organic functional-ization of Ln-doped and co-doped zirconia nanoparticles, and their encapsulation in the PLGA-b-PEG-COOH nanomicelles
A combined electron spin resonance (ESR) and atomic force microscopy (AFM) study on Ce1−xGdxO2−x/... more A combined electron spin resonance (ESR) and atomic force microscopy (AFM) study on Ce1−xGdxO2−x/2samples is here presented, aimed at investigating the evolution of the ESR spectral shape as a function ofxin a wide composition range. At lowx=0.02, the spectrum is composed of features atgeff≈2; 2.8; 6. With increasingx, this pattern merges into a singlegeff≈2broad ESR curve, which assumes a Dysonian-shaped profile atx≥0.5, whereas, at thesexvalues, AFM measurements show an increasing surface roughness. It is suggested that the last could cause the formation of surface polaritons at the origin of the particular ESR spectral profile observed at these high Gd doping levels.
The electrochemical formation of nanotubular titanium oxide films was investigated in 1 M H2SO4 a... more The electrochemical formation of nanotubular titanium oxide films was investigated in 1 M H2SO4 and 0.05–0.4 wt.% HF electrolytes. Depending on anodization condition, i.e. cell voltage, anodization time, HF concentration, TiO2 porous films having different thickness (from 350 to 500 nm) and pore diameter (from 40 to 150 nm) were obtained. By varying the cell voltage from 10 V to 40 V it was possible to
ABSTRACT a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investi... more ABSTRACT a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the plasma membrane of Xenopus laevis oocyte. Different protocols of sample preparation to perform an AFM investigation of both external and intracellular sides of the oocyte plasma membrane are presented and discussed. Reproduc-ible AFM images allowed visualization and dimensional characterization of protein complexes differently arranged on both sides of the oocyte plasma membrane. In particular, two different arrangements were visualized: (1) a heterogeneous and irregular distribution of the protein complexes and (2) in some cases a distribution of nanometer-sized membrane domains where protein complexes are densely packed and spatially arranged in an ordered hexagonal motif. In addition, a methodological approach based on the purification of oocyte plasma membrane by ultracentrifugation on sucrose gradient is also described in this work. The potential of AFM as a useful tool for the structural characterization of proteins in a native eukary-otic membrane was established and its relevance for describing the organization of protein complexes in native biological membranes was explored.
Substituted thiophene systems are a class of stable and processable polymers whose electronic pro... more Substituted thiophene systems are a class of stable and processable polymers whose electronic properties can be tailored by monomer functionalization. The more studied are poly(3-alkylthiophenes) (P3AT's) whose basic crystalline organization features have been established by the work, often requiring nonstandard approaches, of many groups. 1-12 There is consensus on a model in which parallel stacks of polyconjugated main chains organize in layers, with the side chains running in the regions between the stacked main chains (Scheme 1a). Fitting the models to diffraction data in various instances required doubling the interlayer lattice periodicity (a in Scheme 1a). 2,7,9 However, disorder, poor regioregularity, and the scarce pro-pensity to crystallization of the rigid polythiophene chain have so far prevented the actual solution and refinement of the crystal structures of these macromolecules. When enantiopure side chains are attached to the thiophene rings, chiral polythiophenes...
a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the ... more a b s t r a c t This paper describes the use of Atomic Force Microscopy (AFM) to investigate the plasma membrane of Xenopus laevis oocyte. Different protocols of sample preparation to perform an AFM investigation of both external and intracellular sides of the oocyte plasma membrane are presented and discussed. Reproduc-ible AFM images allowed visualization and dimensional characterization of protein complexes differently arranged on both sides of the oocyte plasma membrane. In particular, two different arrangements were visualized: (1) a heterogeneous and irregular distribution of the protein complexes and (2) in some cases a distribution of nanometer-sized membrane domains where protein complexes are densely packed and spatially arranged in an ordered hexagonal motif. In addition, a methodological approach based on the purification of oocyte plasma membrane by ultracentrifugation on sucrose gradient is also described in this work. The potential of AFM as a useful tool for the stru...
Folate decorated organic nanocarriers loaded with magnetite nanoparticles and paclitaxel provide ... more Folate decorated organic nanocarriers loaded with magnetite nanoparticles and paclitaxel provide a specific and prolonged negative contrast of breast cancers on T2-weighted MR images.
ABSTRACT Zirconia nanoparticles doped with Eu 3+ , Tb 3+ and Gd 3+ ions have been synthesized fol... more ABSTRACT Zirconia nanoparticles doped with Eu 3+ , Tb 3+ and Gd 3+ ions have been synthesized following the benzyl alcohol route. The nano-particles were coated with N-hydroxydodecanamide and encapsu-lated in PLGA-b-PEG-COOH nanomicelles. The magnetic and fluorescent properties of these hybrid nanocarriers were investi-gated, proving them to be potential dual-imaging contrast agents. Increasing interest has been focused on the design of nano-materials suitable for use as non-invasive diagnostic tools for biomedical applications. In particular, the combination of optically active components with a contrast agent (CA) for magnetic resonance imaging (MRI) is an attractive way to develop multifunctional probes for biological imaging and recognition. 1 Although many classes of biocompatible organic–inorganic hybrid materials are potentially useful, many presently available formulations require potentially toxic elements, and indeed, clinical translation of nanotechnology will require nano-particles with the lowest possible likelihood of toxicity. 2 Because of its low toxicity, zirconia (ZrO 2) can be considered a potential host matrix for the design and fabrication of inno-vative nanomaterials. 3 Its doping with lanthanides has been reported and, in particular, Eu 3+ was the most used because of its interesting optical properties. 4 Moreover, Gd-doped zirconia was recently studied with the aim of controlling the phase and morphology of the nanocrystals. 5 A tetrakis-based complex of Tb 3+ ions for the doping of amorphous zirconia nanoparticles has been also reported. 6 The synthesis of lanthanide ion doped (Ln-doped) nanoparticles is a well-established method: several synthetic routes have been reported involving wet chemical synthesis such as the sol–gel process, precipitation and micro-emulsion-based methods followed by annealing at high temperature. 7 Post-synthesis functionalization of metal and metal oxide nanoparticles through coating of their surface with organic molecules allows the achievement of stable colloidal disper-sions. Moreover, surface functionalization procedures are aimed at obtaining compatibility between the inorganic phase and the medium where they are supposed to be applied. One of the most important requirements for nanoparticles to be exploited in medicine as diagnostic and therapeutic agents is to be biocompatible and stable in biological media (e.g., phos-phate buffer saline and serum). These requirements are well fullled by coating the nanoparticle surface with biocompatible and biodegradable polymers, and polyethylene glycol (PEG)-based polymers are the most common choice. 8 Another requirement for nano-therapeutic and diagnostic devices is the possibility to be targeted at specic biological sites. These features are usually achieved with polymers known to be non-toxic, i.e. GRAS (Generally Recognized As Safe) or FDA-approved. 9 As a matter of fact, the most investigated nanosized carrier devices are made up of non-toxic micellar amphiphilic polymers that consist of PEG and a low molecular weight hydrophobic core-forming block such as poly(lactic-co-glycolic)-acid (PLGA) or poly(lactic)acid (PLA). The hydrophobic core serves as a natural carrier environment for the inorganic nanoparticles, being suitable also for the inclusion of lipophilic drugs and/or metallic NPs at the same time. The hydrophilic shell allows the stabilization of the whole hybrid nanostructure in aqueous media. 10 Herein, we report the synthesis and the organic functional-ization of Ln-doped and co-doped zirconia nanoparticles, and their encapsulation in the PLGA-b-PEG-COOH nanomicelles
A combined electron spin resonance (ESR) and atomic force microscopy (AFM) study on Ce1−xGdxO2−x/... more A combined electron spin resonance (ESR) and atomic force microscopy (AFM) study on Ce1−xGdxO2−x/2samples is here presented, aimed at investigating the evolution of the ESR spectral shape as a function ofxin a wide composition range. At lowx=0.02, the spectrum is composed of features atgeff≈2; 2.8; 6. With increasingx, this pattern merges into a singlegeff≈2broad ESR curve, which assumes a Dysonian-shaped profile atx≥0.5, whereas, at thesexvalues, AFM measurements show an increasing surface roughness. It is suggested that the last could cause the formation of surface polaritons at the origin of the particular ESR spectral profile observed at these high Gd doping levels.
The electrochemical formation of nanotubular titanium oxide films was investigated in 1 M H2SO4 a... more The electrochemical formation of nanotubular titanium oxide films was investigated in 1 M H2SO4 and 0.05–0.4 wt.% HF electrolytes. Depending on anodization condition, i.e. cell voltage, anodization time, HF concentration, TiO2 porous films having different thickness (from 350 to 500 nm) and pore diameter (from 40 to 150 nm) were obtained. By varying the cell voltage from 10 V to 40 V it was possible to
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Papers by Paolo Arosio