The transmembrane gradient of the dielectric constant influences the DPH lifetime distribution

Konopásek, Ivo; Kvasnička, P.; Amler, Evžen; Curatola, G

doi:10.1016/0014-5793(95)01138-5

Cited by 19 publications

(3 citation statements)

References 15 publications

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“…The population of drug molecules in different environments does not change over a time period in the fluorescence lifetime. The other factor is that drug molecules experience an environment of gradient in the dielectric response which occurs on the length scale of the emitting moiety. − The time components are composed of shorter components (τ 1 ) around 1.1 ns and longer components (τ 2 ) around 4.2, 3.5, and 3.1 for DMPG, DMPC, and DOTAP liposomes (SI Table 2(a), 2(b), and 2(c)). The longer component is attributed to the liposome-bound DOX.…”

Section: Resultsmentioning

confidence: 99%

First Evidence of the Liposome-Mediated Deintercalation of Anticancer Drug Doxorubicin from the Drug–DNA Complex: A Spectroscopic Approach

et al. 2015

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Biocompatible liposomes were used for the first time to study the deintercalation process of a prominent anticancer drug, doxorubicin (DOX), from doxorubicin-intercalated DNA (DOX-DNA complex) under controlled experimental conditions. The study revealed that anionic liposomes (DMPG liposomes) appeared to be the most effective to bring in the highest percentage of drug release while cationic liposomes (DOTAP liposomes) scored the lowest percentage of release. The drug release was primarily attributed to the electrostatic interaction between liposomes and drug molecules. Apart from this interaction, changes in the hydrophobicity of the medium upon addition of liposomes to the DNA-drug solution accompanied by lipoplex formation between DNA and liposomes were also attributed to the observed deintercalation. The CD and the time-resolved rotational relaxation studies confirmed that lipoplex formation took place between liposomes and DNA owing to electrostatic interaction. The confocal study revealed that in the postrelease period, DOX binds with liposomes. The reason behind the binding is electrostatic interaction as well as the unique bilayer structure of liposomes which helps it to act as a "hydrophobic sink" for DOX. The study overall highlighted a novel strategy for deintercalation of drug using biocompatible liposomes, as the release of the drug can be controlled over a period of time by varying the concentration and composition of the liposomes.

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Section: Resultsmentioning

confidence: 99%

First Evidence of the Liposome-Mediated Deintercalation of Anticancer Drug Doxorubicin from the Drug–DNA Complex: A Spectroscopic Approach

et al. 2015

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“…The reciprocal of λ max giving the maximal fluorescence intensity of DOX was proportional to the dielectric constant of solvent ( Figure 1D ).The fluorescence spectrum for DVs showed the emission peak at 590 nm in λ max ( Figure 1C ), corresponding to the bulk aqueous environment (ε ~ 75) (estimated by Figure 1D ). Taking into consideration that the dielectric constantmonotonously changes along the vesicle membrane27, it is considered that DOX would be present at the same dielectric environment as the bulk aqueous phase, although some of DOX might be solubilized at membrane region of Span 80 vesicle.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Cytotoxicity for Colon 26 Cells Using Doxorubicin-Loaded Sorbitan Monooleate (Span 80) Vesicles

Hayashi¹,

Tatsui

Shimanouchi

et al. 2013

Int. J. Biol. Sci.

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Span 80 (sorbitan monooleate) vesicles behaved differently from conventional phospholipid vesicles (liposomes) because the former had a more fluid interface. After doxorubicin hydrochloride (DOX) was encapsulated into the Span 80 vesicle (loading efficiency: 63 %), DOX-loaded Span 80 vesicles (DVs) were thereafter added to Colon 26 cells. It was suggested, from the flow cytometric analysis and confocal laser microscopic observation, that DVs directly deliver DOX into the cytoplasm of Colon 26 cells. DVs showed the different delivery manner from the DOX-loaded liposomes (DLs). It is considered that the difference of delivery manner between DVs and DLs resulted in the difference of cytotoxicity (IC50); i.e. IC50 values for DVs and DLs were 5 and > 30 μM, respectively. The results obtained herein would give the fundamental findings which can contribute to the improvement of formulation of conventional liposome-based carrier and its cytotoxicity.

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“…As shown in Figure c, no significant variation in the relative permittivity was observed among the various liposomes tested here, although a slight increase in values was observed in the case of DMPC. It has been reported that there is a gradient of relative permittivity (ε) in the vertical direction across the lipid bilayer membrane, where the ε value of the phosphocholine and glycerol regions can be estimated as approximately 60 and 40, respectively …”

Section: Resultsmentioning

confidence: 99%

Liposome Modified with Mn−Porphyrin Complex Can Simultaneously Induce Antioxidative Enzyme-like Activity of Both Superoxide Dismutase and Peroxidase

et al. 2008

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An antioxidative liposome catalysis that mimics both superoxide dismutase (SOD) and peroxidase (POD) activities has been developed by using the liposomes modified with lipophilic Mn-(5,10,15,20-tetrakis[1-hexadecylpyridium-4-yl]-21H,23H-porphyrin) (Mn-HPyP). The SOD- and POD-like activities of the Mn-HPyP-modified liposome were first investigated by varying the type of phospholipid, such as 1,2-distearyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC). Higher SOD-like activity was obtained in the case of DLPC and DMPC liposomes, in which the ligands were well-dispersed on the membrane in the liquid crystalline phase. The POD-like activity was maximal in the case of DMPC liposome, in which the Mn-HPyP complex was appropriately clustered on the membrane in the gel phase. On the basis of the above results, the co-induction of the SOD and POD activities to eliminate the superoxide and also hydrogen peroxide as a one-pot reaction was finally performed by using the Mn-HPyP-modified DMPC liposome, resulting in an increase in the efficiency of the elimination of both superoxide and hydrogen peroxide.

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The transmembrane gradient of the dielectric constant influences the DPH lifetime distribution

Cited by 19 publications

References 15 publications

First Evidence of the Liposome-Mediated Deintercalation of Anticancer Drug Doxorubicin from the Drug–DNA Complex: A Spectroscopic Approach

First Evidence of the Liposome-Mediated Deintercalation of Anticancer Drug Doxorubicin from the Drug–DNA Complex: A Spectroscopic Approach

Enhanced Cytotoxicity for Colon 26 Cells Using Doxorubicin-Loaded Sorbitan Monooleate (Span 80) Vesicles

Liposome Modified with Mn−Porphyrin Complex Can Simultaneously Induce Antioxidative Enzyme-like Activity of Both Superoxide Dismutase and Peroxidase

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