Porphyrin–phospholipid interaction and ring metallation depending on the phospholipid polar head type

Ramos, Ana Paula; Pavani, Christiane; Iamamoto, Yassuko; Zaniquelli, Maria Elisabete Darbello

doi:10.1016/j.jcis.2010.06.021

Cited by 17 publications

(10 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Langmuir monolayers may be considered as model systems of liposome-type drug carriers or even cell membranes [10]. It is known that HP easily forms aggregates; hence, in order to overcome this effect and supply monomeric HP in the formulation for clinical use, it is necessary to look for appropriate carriers.…”

Section: Measurementsmentioning

confidence: 99%

“…Recently, it has been shown that an understanding of the interactions between the photosensitizer and components of the biological membranes such as lipids is essential for PDT effectiveness [10,11].…”

Section: Introductionmentioning

confidence: 99%

“…The Langmuir method of the production of monolayers on the water subphase permits investigation of the incorporation and interaction of the photoactive molecules in biological membranes [10], determining their in vivo activity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Photophysical and Thermodynamic Parameters of Hematoporphyrin in Solutions and Monolayers

2012

View full text Add to dashboard Cite

To achieve better understanding of anticancer photosensitizing efficiency and cellular membrane location ability, a study of hematoporphyrin and phospholipids in a dye and in a mixture of a dye and lipids in volumetric and 2D systems was performed. By means of steady-state absorption, fluorescence, and time-resolved optoacoustic spectroscopy, the fluorescence quantum yield, the fraction of absorbed energy converted into heat on a subnanosecond timescale, the efficiency of the dye's triplet-state population, and singlet oxygen generation characteristics of the dye were determined in chosen organic solvents. On the basis of the isotherms of hematoporphyrin and its mixture with phospholipid in Langmuir monolayers, the excess area, excess Gibbs energy, and compression modulus were estimated and the molecular interactions in the model systems investigated were discussed.

show abstract

Section: Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photophysical and Thermodynamic Parameters of Hematoporphyrin in Solutions and Monolayers

2012

View full text Add to dashboard Cite

show abstract

“…The electrostatic interactions between cationic species and anionic liposomes are strong enough to lead to adsorption of molecules onto lipid membranes. [34][35][36][37][38][39][40] In this work, we used this interaction to self-assemble the different components of a photocatalytic system on a well-defined nanostructure, namely, phospholipid vesicles bearing a positive or negative charge density. The adsorption of a charged dye onto the surface of a charged liposome, and the subsequent electron transfer to an electron acceptor (EA) that in the reduced form might be repelled from the liposome surface has been investigated.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Photoinduced Electron Transfer at the Surface of Charged Lipid Bilayers

Limburg

Laisné

Bouwman

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

Photocatalytic systems often suffer from poor quantum yields due to fast charge recombination: The energy-wasting annihilation of the photochemically created charge-separated state. In this report, we show that the efficiency of photoinduced electron transfer from a sacrificial electron donor to positively charged methyl viologen, or to negatively charged 5,5'-dithiobis(2-nitrobenzoate), increases dramatically upon addition of charged phospholipid vesicles if the charge of the lipids is of the same sign as that of the electron acceptor. Centrifugation and UV/Vis titration experiments showed that the charged photosensitizers adsorb at the liposome surface, that is, where the photocatalytic reaction takes place. The increased photoelectron transfer efficiency in the presence of charged liposomes has been ascribed to preferential electrostatic interactions between the photosensitizer and the membrane, which prevents the formation of photosensitizer-electron-acceptor complexes that are inactive towards photoreduction. Furthermore, it is shown that the addition of liposomes results in a decrease in photoproduct inhibition, which is caused by repulsion of the reduced electron acceptor by the photocatalytic site. Thus, liposomes can be used as a support to perform efficient photocatalysis; the charged photoproducts are pushed away from the liposomes and represent "soluble electrons" that can be physically separated from the place where they were generated.

show abstract

“…Although the electrostatic interaction between phospholipids and alkali or alkaline earth metal cations, like Na + and Ca 2 + , have been extensively investigated, [13][14][15][16][17][18][19][20][21][22][23][24][25] to date very few studies report on the interaction of transition-metal complexes with phospholipid membranes. [7,[26][27][28][29][30][31][32] In particular, in spite of the growing number of ruthenium-based anticancer compounds their interaction with phospholipid membranes remains essentially unexplored, with the exception of one study on the adsorption of the highly charged ruthenium red cations on phospholipid bilayers. [33] In all studies about metal-lipid interactions, the role of electrostatics has only been investigated from a thermodynamic point of view, and kinetic aspects have been mostly ignored.…”

Section: Introductionmentioning

confidence: 99%

Binding of a Ruthenium Complex to a Thioether Ligand Embedded in a Negatively Charged Lipid Bilayer: A Two‐Step Mechanism

Bahreman

Rabe

Kros

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

The interaction between the ruthenium polypyridyl complex [Ru(terpy)(dcbpy)(H2O)](2+) (terpy = 2,2';6',2"-terpyridine, dcbpy = 6,6'-dichloro-2,2'-bipyridine) and phospholipid membranes containing either thioether ligands or cholesterol were investigated using UV-visible spectroscopy, Langmuir-Blodgett monolayer surface pressure measurements, and isothermal titration calorimety (ITC). When embedded in a membrane, the thioether ligand coordinated to the dicationic metal complex only when the phospholipids of the membrane were negatively charged, that is, in the presence of attractive electrostatic interaction. In such a case coordination is much faster than in homogeneous conditions. A two-step model for the coordination of the metal complex to the membrane-embedded sulfur ligand is proposed, in which adsorption of the complex to the negative surface of the monolayers or bilayers occurs within minutes, whereas formation of the coordination bond between the surface-bound metal complex and ligand takes hours. Finally, adsorption of the aqua complex to the membrane is driven by entropy. It does not involve insertion of the metal complex into the hydrophobic lipid layer, but rather simple electrostatic adsorption at the water-bilayer interface.

show abstract

Porphyrin–phospholipid interaction and ring metallation depending on the phospholipid polar head type

Cited by 17 publications

References 26 publications

Photophysical and Thermodynamic Parameters of Hematoporphyrin in Solutions and Monolayers

Photophysical and Thermodynamic Parameters of Hematoporphyrin in Solutions and Monolayers

Enhanced Photoinduced Electron Transfer at the Surface of Charged Lipid Bilayers

Binding of a Ruthenium Complex to a Thioether Ligand Embedded in a Negatively Charged Lipid Bilayer: A Two‐Step Mechanism

Contact Info

Product

Resources

About