http://www.cnr.it/ontology/cnr/individuo/prodotto/ID39571
Amphiphilic Cyclodextrin Carriers Embedding Porphyrins: Charge and Size Modulation of Colloidal Stability in Heterotopic Aggregates (Articolo in rivista)
- Type
- Label
- Amphiphilic Cyclodextrin Carriers Embedding Porphyrins: Charge and Size Modulation of Colloidal Stability in Heterotopic Aggregates (Articolo in rivista) (literal)
- Anno
- 2005-01-01T00:00:00+01:00 (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
- 10.1021/jp0501998 (literal)
- Alternative label
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Antonino Mazzaglia; Nicola Angelini; Domenico Lombardo; Norberto Micali; Salvatore Patane; Valentina Villari; Luigi Monsu Scolaro (literal)
- Pagina inizio
- Pagina fine
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
- Rivista
- Note
- ISI Web of Science (WOS) (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- Istituto per lo Studio dei Materiali Nanostrutturati, ISMN-CNR,
Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica,
Dipartimento di Fisica della Materia e Tecnologie Fisiche AVanzate, UniVersita` di Messina, Salita Sperone 31, 98166 Messina, Italy
Istituto per i Processi Chimico Fisici, IPCF-CNR, Sezione di Messina, Via La Farina, 237, 98123 Messina, Italy (literal)
- Titolo
- Amphiphilic Cyclodextrin Carriers Embedding Porphyrins: Charge and Size Modulation of Colloidal Stability in Heterotopic Aggregates (literal)
- Abstract
- The interaction between the anionic 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphyrin (TPPS) and
cationic vesicles formed by heptakis(2-ù-amino-O-oligo(ethylene oxide)-6-hexylthio)-â-cyclodextrin (SC6CDNH2)
has been investigated in detail through a combination of elastic light scattering (ELS), quasi-elastic light
scattering (QELS), zeta potential measurements, and time-resolved fluorescence anisotropy. ELS experiments
provided the first structural characterization of these cationic vesicles both in the absence and in the presence
of TPPS porphyrin, modeling the system as a spherical particle described by a single thin shell form factor.
The structure of mixed hetero-aggregates is modulated by charge and size of the two components as function
of different porphyrin/cyclodextrin (CD) molar ratios. At the limiting molar ratio studied, the absolute value
of zeta potential (|æ|= 12.5 mV) seems to be a reference value for the formation of stable colloidal CD
vesicular aggregates at thermodynamic equilibrium. New insights on the structure of these heterotopic colloids
have been obtained by analysis of rotational correlation times at different molar ratios exploiting time-resolved
fluorescence anisotropy experiments. At high porphyrin loads, the anisotropy decays behave as monoexponentials
and the rotational correlation times (1-2 ns) together with the r0 values close to zero suggest the
presence of small amounts of TPPS embedded in a hydrophobic environment either in monomeric or in
aggregated form. At the lower porphyrin/CD molar ratios, the anisotropy decays exhibit a double-exponential
behavior showing a predominant component with a slow rotational correlation time (20-25 ns) and limiting
anisotropy values of ~0.15. This component has been assigned to molecules that are more stabilized onto the
CD vesicles, that is, porphyrins embedded into the oligo-ethylene wall of the CD vesicles. Scanning nearfield
optical microscopy of the samples evaporated on glass surfaces gave further insights on the morphology
and optical properties of these systems, confirming the embedding of TPPS on the vesicles and evidencing
the role of the solvent. (literal)
- Prodotto di
- Autore CNR
Incoming links:
- Prodotto
- Autore CNR di
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#rivistaDi
