-
[show abstract]
[hide abstract]
ABSTRACT: This contribution reports the design, preparation, and characterization of nanostructured hybrid films of silver nanoparticles (AgNPs) and a tailored nitric oxide (NO) photodonor. They were achieved by exploiting effective interfacial interactions between an amino-terminated NO photodonor spread onto water surface and naked AgNPs dissolved in the water subphase. The morphology, the spectroscopic features, and the interaction between the two components in the floating films at the air/water interface were inspected by Brewster Angle Microscopy, UV-Vis reflection, and polarization-modulation infrared reflection-absorption spectroscopy. AgNPs and the NO photodonor were successfully transferred onto hydrophobized quartz substrates by horizontal lifting deposition and the resulting multilayer films were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy, respectively. The results obtained showed the presence of both isolated AgNPs and assemblies of AgNPs having nanodimensional character in the films. The photochemical properties of the NO photodonor were well preserved in the hybrid multilayers. In fact, they were able to release NO under visible light excitation, as unambiguously demonstrated by the direct and in real-time monitoring of this transient species using an ultrasensitive electrode, and the transfer of the released NO to a protein such as myoglobin.
Journal of Colloid and Interface Science 02/2012; 368(1):191-6. · 3.07 Impact Factor
-
Chemistry - An Asian Journal 01/2012; 7(1):50-4. · 4.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We have developed a supramolecular nanoassembly capable of inducing remarkable levels of cancer cell mortality through a bimodal action based on the simultaneous photogeneration of nitric oxide (NO) and singlet oxygen ((1)O(2)). This was achieved through the appropriate incorporation of an anionic porphyrin (as (1)O(2) photosensitizer) and of a tailored NO photodonor in different compartments of biocompatible nanoparticles based on cationic amphiphilic cyclodextrins. The combination of steady-state and time-resolved spectroscopic techniques showed the absence of significant intra- and interchromophoric interaction between the two photoactive centers embedded in the nanoparticles, with consequent preservation of their photodynamic properties. Photodelivery of NO and (1)O(2) from the nanoassembly on visible light excitation was unambiguously demonstrated by direct and real-time monitoring of these transient species through amperometric and time-resolved infrared luminescence measurements, respectively. The typical red fluorescence of the porphyrin units was essentially unaffected in the bichromophoric nanoassembly, allowing its localization in living cells. The convergence of the dual therapeutic action and the imaging capacities in one single structure makes this supramolecular architecture an appealing, multifunctional candidate for applications in biomedical research.
Chemistry 12/2011; 18(6):1684-90. · 5.93 Impact Factor
-
ChemMedChem 06/2011; 6(9):1551-4, 1534. · 3.15 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Hybrid gold nanoclusters exhibiting photoregulated release of nitric oxide are obtained by appropriate self-assembling of a suitable host, a photoactivable guest and Au nanoparticles. The excitation of the core, the shell or both components of the nanoclusters with visible light, together with their dark stability and water solubility, make these nanoarchitectures intriguing candidates to be tested in biomedical research studies.
New Journal of Chemistry 11/2010; 35(1):52. · 2.61 Impact Factor
-
Annalen der Chemie und Pharmacie 12/2009; 2010(3):421 - 426. · 3.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We have designed and synthesized a novel photoactivable molecular conjugate integrating three basic components in its molecular skeleton: a DNA intercalator, a viologen moiety and a nitric oxide (NO) photodonor. This compound is soluble in aqueous solution and binds to double strand DNA with an association constant of 1.1 x 10(4) M(-1). The fluorescence of the intercalator unit is strongly quenched due to an intramolecular electron transfer involving the adjacent viologen moiety. Laser flash photolysis measurements provide direct evidence that, in the presence of DNA, this process is followed by a second electron transfer from DNA to the oxidized intercalator, leading to nucleobase oxidation. Also, the light absorbed by the NO photodonor results in the simultaneous release of NO nearby DNA as confirmed by the direct monitoring of this transient species through an ultrasensitive NO electrode. In this view, this conjugate represents an intriguing model system for photoactivable "dual-function" compounds for biomedical research.
Photochemical and Photobiological Sciences 11/2009; 8(11):1534-8. · 2.58 Impact Factor
-
Chemistry 07/2009; 15(28):6802-6. · 5.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: 2,6-di-O-benzyl- (9), 2-O-benzyl-3,4-O-isopropylidene- (19), and 2-O-benzyl-6-O-m-chlorobenzoyl-L-arabino-hexos-5-ulose (20) have been prepared using 4'-deoxy-4'-eno- and 6'-deoxy-5'-eno lactose dimethyl acetal derivatives 7 and 14 as key intermediates. The synthesis of enol ethers 7 and 14 has been performed with good yields by base-promoted elimination of acetone or p-toluenesulfonic acid from 2',6'-di-O-benzyl-, and 6'-O-p-toluenesulfonyl-2,3:5,6:3',4'-tri-O-isopropylidenelactose dimethyl acetal, respectively. The epoxidation with MCPBA of 7 and 14 in methanol or dichloromethane furnishes C-5'-methoxy and C-5'-m-chlorobenzoyloxy derivatives, easily transformed with good yields into L-arabino 5-ketoaldohexoses 9, 19 and 20.
Carbohydrate Research 11/2003; 338(22):2349-58. · 2.33 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Cyclopropanation reactions of 6-deoxyhex-5-enopyranosides by methylene-zinc-iodide complex, dichlorocarbene, and rhodium ethoxycarbonyl complex addition afford optimum yields of the corresponding spirocyclopropanes. Surprisingly, a stereospecific spirocyclopropane derivative with the two halogens on the upper face of the 4-hydroxy substituent is obtained. To get more insight on the dichlorocarbene cyclopropanation process a computational study, based on DFT quantomechanic calculation was conducted.Graphical abstract
Tetrahedron. 64(37):8652-8658.
