Surface potential of lipid membrane estimated from the partitioning of methylene blue into liposomes

Nakagaki, Masayuki; Katoh, Izumi; Handa, Tetsurou

doi:10.1021/bi00511a021

Cited by 20 publications

(13 citation statements)

References 20 publications

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“…Egg-yolk phosphatidylcholine liposomes loaded with methylene blue (MB) were studied by optical manipulation. MB stands as an interesting potential photosensitizer, candidate for improving the efficacy of photodynamic therapy as it can be located in the aqueous compartments of neutral or positively charged liposomes (Gabrielli et al, 2004;Nakagaki et al, 1981). The shear modulus and the bending moduli were calculated by measuring the optical forces and the induced deformations of the liposomes.…”

Section: Introductionmentioning

confidence: 99%

Measurements of liposome biomechanical properties by combining line optical tweezers and dielectrophoresis

Spyratou

Cunaj

Tsigaridas

et al. 2014

Journal of Liposome Research

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Liposomes are well-known cell simulators and are currently studied as drug delivery systems, for a targeted delivery of higher drug concentrations, in specific cells. Novel biophotonic techniques for manipulation and characterization of liposomes have been developed; among which are optical tweezers. In our work, we demonstrate a novel use of line optical tweezers to manipulate and cause liposome deformations. Optical forces induce tension on liposomes, which are stretched along the line optical trap. The method of dielectrophoresis, combined with optical tweezers, was used to measure the exerted optical forces. As a consequence, in the case of reversible liposome deformations, the value of the shear and bending moduli of liposomes was calculated. We anticipate that the selective manipulation of liposomes will help us toward a better understanding of the cellular-liposome interactions. Studying the biomechanical properties of liposomes will provide an insight into the mechanical behavior of individual living cells, which have recently been implicated in many aspects of human physiology and patho-physiology. The biomechanical properties of cells (i.e. deformability, stiffness and elasticity) can be useful biomarkers for various disease processes and changes of the cell state.

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Section: Introductionmentioning

confidence: 99%

Measurements of liposome biomechanical properties by combining line optical tweezers and dielectrophoresis

Spyratou

Cunaj

Tsigaridas

et al. 2014

Journal of Liposome Research

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“…The appearance of this spectrum indicates that the MB oligomers were released from the inner cavity of the liposome to the solution and decomposed into MB monomers owing to the decrease in MB concentration. Meanwhile, the original absorption maximum at 590 nm shifted to a longer wavelength by 20 nm, possibly because of the change in MB oligomers to dimers (Nakagaki et al, 1981). A substantial increase in the absorption in MB monomer peak and a decrease in MB dimer peak with the addition of Triton X-100 into probe solution were observed (curve c).…”

Section: Characteristic Of Mb-loaded Liposomal Nanoprobesmentioning

confidence: 96%

Combining 3D graphene-like screen-printed carbon electrode with methylene blue-loaded liposomal nanoprobes for phospholipase A2 detection

Zhang

Dong

et al. 2019

Biosensors and Bioelectronics

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Phospholipase A 2 (PLA 2) enzyme could be acted as a unique biomarker for forecasting and diagnosing certain diseases. Therefore, it is important to monitor PLA 2 activity in biological and clinical samples. In this work, a simple electrochemical assay for PLA 2 activity was developed based on a screen-printed carbon electrode (SPCE) with 3D graphene-like surface. When the PLA 2-containing sample was mixed with the nanoprobes, i.e. the electroactive marker methylene blue (MB) encapsulated within nanometer-sized phospholipid liposomes, MB was released and adsorbed/enriched in site onto the surface of SPCE in a micro-cell. The encapsulation and enzymatic release of MB were evaluated using UV-Vis and fluorescence. The peak current due to oxidation of the adsorbed MB on the SPCE was measured by square-wave voltammetry (SWV). The current was directly linear to the PLA 2 activity from 5 U/L to 200 U/L with a detection limit of 3 U/L. The same method can also be used for screening PLA 2 inhibitors. Thus, the enrichment strategy developed in this work could be a promising signal amplification method for the sensitive and selective detection of PLA 2 in biological or clinical samples.

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“…The multilamellar vesicles formed were sonicated at 15 °C for 60 s X 2 followed by centrifugation at 100000g for 1 h. The supernatant containing the unilamellar vesicles was aspirated and assayed for lipid concentration. Membrane surface potential was calculated from the partitioning of methylene blue (MB) into the bilayer (Nakagaki et al, 1981) as a function of increasing concentrations of anionic phospholipid. Liposomes (0.02-0.3 mg/mL) were incubated with gentamicin (10"4 M) for 60 min prior to incubation with MB (2 X 10"5 1 Abbreviations: EB, energy of activation; MB, methylene blue; PA, phosphatidic acid with acyl chains in ester linkage; PA*, phosphatidic acid with alkyl chains in ether linkage; PC, phosphatidylcholine.…”

Section: Methodsmentioning

confidence: 99%

“…From the partitioning of MB in the membrane the membrane surface electrostatic potential ( ) can be calculated by using the equation derived by Nakagaki et al (1981) = 2.30(A:7ye)(log K0 -log K)…”

Section: Methodsmentioning

confidence: 99%

The effect of gentamicin on the biophysical properties of phosphatidic acid liposomes is influenced by the O-C=O group of the lipid

Ramsammy¹,

Kaloyanides²

1988

Biochemistry

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We previously reported that gentamicin binds to liposomes composed of anionic phospholipids and depresses glycerol permeability and raises the activation energy for glycerol permeation in these liposomes. We postulated that these changes in the glycerol permeability and in the activation energy (Ea) for glycerol permeation were due to hydrogen bonding between O-C = O groups in the hydrogen belt and one or more amino groups of gentamicin. To test this hypothesis, we examined the effects of gentamicin on the membrane surface potential, the glycerol permeability coefficient (p), the Ea for glycerol permeation, and the aggregation of liposomes composed of 1:1 phosphatidylcholine (PC) and phosphatidic acid with the acyl chains of phosphatidic acid in either an ester (PA) or an ether (PA*) linkage. Gentamicin depressed the membrane surface electrostatic potential, measured by the partitioning of methylene blue between the bulk solution and the liposomal membrane, to an equivalent degree in PC-PA and PC-PA* liposomes, which indicates that substitution of the ether for the ester linkage did not interfere with the electrostatic interaction between the cationic drug and the negatively charged phosphate head group. Gentamicin caused a temperature-dependent decrease of p and raised Ea for glycerol permeation from 17.7 +/- 0.3 to 21.6 +/- 0.4 kcal/mol in PC-PA liposomes but had little or no effect on these parameters in PC-PA* liposomes. In contrast, gentamicin induced a significantly greater degree of aggregation of PC-PA* liposomes compared to that of PC-PA liposomes.(ABSTRACT TRUNCATED AT 250 WORDS)

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Surface potential of lipid membrane estimated from the partitioning of methylene blue into liposomes

Cited by 20 publications

References 20 publications

Measurements of liposome biomechanical properties by combining line optical tweezers and dielectrophoresis

Measurements of liposome biomechanical properties by combining line optical tweezers and dielectrophoresis

Combining 3D graphene-like screen-printed carbon electrode with methylene blue-loaded liposomal nanoprobes for phospholipase A2 detection

The effect of gentamicin on the biophysical properties of phosphatidic acid liposomes is influenced by the O-C=O group of the lipid

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