Distribution of ion pairs into a bilayer lipid membrane and its effect on the ionic permeability

Omatsu, Terumasa; Hori, Kisho; Ishida, Naoto; Maeda, Kohji; Yoshida, Yumi

doi:10.1016/j.bbamem.2021.183724

Cited by 2 publications

(14 citation statements)

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“…We have evaluated the distribution constants (K D ) of the R6G + salts of these anions into lipid bilayers by conducting liposome experiments in the previous work (Table 1). 15 The degree of accumulation of R6G + in the inner aqueous phase increases as K D increases; therefore, the more hydrophobic the anion, the greater the accumulation of R6G + in the lipid bilayer.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The pairs of cations and anions that are present in the membrane govern the membrane permeation rate of ionic molecules. 14,15 The distribution constants of cations and anions can be evaluated from extraction experiments using liposomes. 13 Considering the ion pair distribution model, the addition of target cations and hydrophobic anions to the outer aqueous phase of liposomes causes the cations to distribute with the hydrophobic anions into the lipid membrane and uphill accumulate in the inner aqueous phase of the liposome.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In the previous electrochemical measurement for the ion transport across the planar BLM, we have found that the transmembrane current (flux) of ions is proportional to the concentration of each ion in the membrane and expressed as a function of the ionic concentration in the membrane and the artificially applied membrane potential. 15 In the present work, we extend the theoretical equation for the transmembrane current density to the ionic accumulation into the vesicle. The transmembrane current density (I ion ) of the corresponding ionic species as a function of membrane potential (E BLM ), which is defined as the potential of the inner aqueous phase relative to that of the outer aqueous phase of the GUV, is expressed by…”

mentioning

confidence: 97%

“…We have previously proposed the distribution mechanism of cations and anions in bilayer lipid membranes 13 and demonstrated that the concentration of respective ions in the membrane governs the membrane permeation rate. 14,15 We now discuss the accumulation of R6G + in the inner aqueous phase of the GUV according to the distribution mechanism. R6G + and X − in the outer aqueous phase (W out ) first distribute in the lipid bilayer of the GUV (BLM) and then migrate to the inner aqueous phase (W in ), as shown in Figure 1.…”

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Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions

et al. 2022

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The "uphill (against the concentration gradient)" accumulation of a hydrophobic cation (rhodamine 6G, R6G + ) into the inner phase of a giant unilamellar vesicle (GUV) was realized with the concentration gradient of the counter anion (X − = ClO 4 − , BF 4 − , or Br − ) in the presence of phosphate buffer (P − , pH = 7) in the inner and outer phase of the GUV and detected as the increase of the R6G + fluorescence intensity in the inner phase using a confocal laser scanning fluorescence microscope. The addition of X − in the outer phase of the GUV caused the accumulation of R6G + in the inner phase. The degree and kinetics of the accumulation were dependent on the concentration and type of X − ; e.g., the inner concentration of R6G + reached 2.5 times that in the outer phase of GUV after adding 10 mM ClO 4 − . The accumulation was theoretically simulated by assuming the distribution of ion pairs (R6G + and X − , R6G + , and P − ) between the aqueous phase and the lipid bilayer membrane (ion pair distribution model) and the transmembrane fluxes of R6G + , X − and P − . The theoretical simulation rationalized the accumulation degree and kinetics of the experimental results. The accumulation of the target cation by the concentration gradient of the counter anion demonstrated in this study can be an effective method for the preparation of liposomal drugs.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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confidence: 97%

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confidence: 99%

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Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions

et al. 2022

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“…Based on these mechanisms, it is difficult to explain the steady-state current observed at a constant membrane potential. On the other hand, Murakami, et al and Omatsu, et al pointed out that not only the transport of a coexisting counterion across the BLM but also the adsorption and desorption of rhodamine 6G on the surface of the BLM [32][33][34]. Nevertheless, the waveform of cyclic voltammograms in the presence of hydrophobic ions has not accurately been analyzed yet.…”

Section: Introductionmentioning

confidence: 99%

Ion transport across bilayer lipid membranes in the presence of tetraphenylborate

et al. 2022

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A pair of symmetrical cathodic and anodic peaks is observed in cyclic voltammograms for the ion transport across a bilayer lipid membrane (BLM) between two aqueous phases in the presence of tetraphenylborate (TPhB -). Although TPhBserves as a carrier of a hydrophilic counter ion (Na + ) under the steady-state condition, the reason for the appearance of symmetrical peaks has not been clearly explained until now. From the chronoamperometric analysis, it is turned out that the symmetrical peaks are attributed to the translocation of TPhBbetween two adsorbed layers on the surface of the BLM.

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Distribution of ion pairs into a bilayer lipid membrane and its effect on the ionic permeability

Cited by 2 publications

References 51 publications

Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions

Uphill Accumulation of Ionic Species into a Lipid Vesicle by the Concentration Gradient of Counter Ions

Ion transport across bilayer lipid membranes in the presence of tetraphenylborate

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