Differential dielectroscopic data on the relation of erythrocyte membrane skeleton to erythrocyte deformability and flicker

Ivanov, Ivan T.; Paarvanova, Boyana

doi:10.1007/s00249-020-01491-4

Cited by 9 publications

(41 citation statements)

References 81 publications

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“…After the removal of the deformation force the electric energy, accumulated as dielectric polarization in the spectrin laments, could be transformed, through the reversed piezo effect, back into mechanical force helping to restore the initial shape of the deformed membrane. Such a mechanistic view about the involvement of spectrin network in the elasticity and icker of RBC membrane is supported by recent ndings that the strength of β sp relaxation senses the arti cially induced changes in the deformability and icker of RBC plasma membrane [11].…”

Section: Discussionmentioning

confidence: 88%

“…The presence of two comparable by area perfect semicircle arcs on the admittance contribution plot, ΔY" vs. ΔY', (Fig. 2a, full circles) has been attributed to two single-time dielectric relaxations on spectrin network, designated as β sp and γ1 sp , respectively [11]. The upper (positive) semicircle arc expressed the β sp relaxation while the lower (negative) semicircle arc revealed the γ1 sp relaxation.…”

Section: Resultsmentioning

confidence: 95%

“…Here, j is the imaginary unit, j 2 = -1. The values of Y* and C* were measured at 16 frequencies between 30 kHz and 15 MHz, and scanned sequentially with an integration time of 1 s. The experimental set-up, designed to collect the raw thermal dielectroscopy data was shown previously [11]. The inter-electrode voltage was 100 mV creating eld far weaker than those used for dielectrophoresis of RBCs [22].…”

Section: Preparation Of Triton-x-100 Shells Of Rbc Ghost Membranesmentioning

confidence: 99%

“…Compared to the former, the latter component was small and linear because it was not caused by the denaturation of protein and arose within a relatively narrow temperature interval. Hence, it was determined for an equivalent temperature interval prior to spectrin denaturation and subtracted from the apparent changes in Y', Y", C' and C" at T A as described previously [11,16]. This temperature correction extracted the spectrin-linked portion of the dielectric changes at T A (for details see the Fig.…”

Section: Dielectric Loss Curve Of the Suspensions Of Rbcs Rbc Ghost M...mentioning

confidence: 99%

“…3.1. Model representation of the dielectric relaxations on spectrin network of RBCs and RBC ghost membranes.In this study, the β sp and γ1 sp relaxations on the ΔY" vs. ΔY' plot were modeled by an appropriate equivalent electric circuit as described recently[11, 16]. The model representation was used to better differentiate the two relaxations and describe them by quantitative parameters.…”

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Role of the lipid bilayer at the dielectric relaxations in human erythrocytes

Ivanov¹,

Paarvanova²

2023

Preprint

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Using the dielectric changes in red blood cells (RBCs) at the temperature of spectrin dissociation and denaturation, TA, two dielectric relaxations have been detected on spectrin network, βsp relaxation at 1.4 MHz and γ1sp relaxation at 9 MHz. In this study, the βsp relaxation was linearly strengthened on increasing the ion accumulation at either side of RBC plasma membranes, while the strength of γ1sp relaxation remained unaffected. In Triton shells, produced by mild extraction of RBC ghost membrane lipids by Triton-X-100 (up to 0.1%) and in RBCs, treated by acid medium (pH 5.2), known to disconnect the glycophorin C integral protein from the actin-spectrin junction, the βsp relaxation was strongly to fully inhibited while γ1sp relaxation was preserved. In RBCs, acid-treated RBCs, RBC ghost membranes and Triton-X shells the capacitance contribution and dielectric loss curve of spectrin network were both positive for βsp relaxation and negative for γ1sp relaxation. The above results support the view that βsp relaxation exhibits piezo effect on spectrin network prior to TA, powered by the electrodeformation of lipid membrane mainly through the glycophorin C-actin-spectrin bridge. This piezo effect adds strength (~ 25%) to the interfacial polarization of RBC lipid membrane and could be adjuvant factor in the elasticity and flicker of RBC membrane. The results and the amended equivalent circuit of RBC suspension support the claim that γ1sp relaxation reflects direct interaction and resonance of the field with the natural oscillations of dipoles (segments) of spectrin tetramers.

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Section: Discussionmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 95%

Section: Preparation Of Triton-x-100 Shells Of Rbc Ghost Membranesmentioning

confidence: 99%

Section: Dielectric Loss Curve Of the Suspensions Of Rbcs Rbc Ghost M...mentioning

confidence: 99%

mentioning

confidence: 99%

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Role of the lipid bilayer at the dielectric relaxations in human erythrocytes

Ivanov¹,

Paarvanova²

2023

Preprint

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Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes

Ivanov,

Paarvanova

2023

Bioelectromagnetics

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Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, βsp (1.4 MHz) and γ1sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the βsp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4‐fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i‐erythritol) inhibited both the βsp and γ1sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the βsp relaxation, whereas at band 3‐spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1sp relaxation.

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