Properties Of Erythrocyte Membrane Research Articles

Erythrocyte Membrane Camouflaged Nanotheranostics for Optical Molecular Imaging-Escorted Self-Oxygenation Photodynamic Therapy.

Hypoxic tumor microenvironment (TME) hampers the application of oxygen (O2)-dependent photodynamic therapy (PDT) in solid tumors. To address this problem, a biomimetic nanotheranostics (named MMCC@EM) is developed for optical molecular imaging-escorted self-oxygenation PDT. MMCC@EM is synthesized by encapsulating chlorin e6 (Ce6) and catalase (CAT) in metal-organic framework (MOF) nanoparticles with erythrocyte membrane (EM) camouflage. Based on the biomimetic properties of EM, MMCC@EM efficiently accumulates in tumor tissues. The enriched MMCC@EM achieves TME-activatable drug release, thereby releasing CAT and Ce6, and this process can be monitored through fluorescence (FL) imaging. In addition, endogenous hydrogen peroxide (H2O2) will be decomposed by CAT to produce O2, which can be reflected by the measurement of intratumoral oxygen concentration using photoacoustic (PA) imaging. Such self-oxygenation nanotheranostics effectively mitigatetumor hypoxia and improve the generation of singlet oxygen (1O2). The 1O2 disrupts mitochondrial function and triggers caspase-3-mediated cellular apoptosis. Furthermore, MMCC@EM triggers immunogenic cell death (ICD) effect, leading to an increased infiltration of cytotoxic T lymphocytes (CTLs) into tumor tissues. As a result, MMCC@EM exhibits good therapeutic effects in 4T1-tumor bearing mice under the navigation of FL/PA duplex imaging.

Erythrocytes' surface properties and stiffness predict survival and functional decline in ALS patients.

Erythrocytes play a fundamental role in oxygen delivery to tissues and binding to inflammatory mediators. Evidences suggest that dysregulated erythrocyte function could contribute to the pathophysiology of several neurodegenerative diseases. We aimed to evaluate changes in morphological, biomechanical, and biophysical properties of erythrocytes from amyotrophic lateral sclerosis (ALS) patients, as new areas of study in this disease. Blood samples were collected from ALS patients, comparing with healthy volunteers. Erythrocytes were assessed using atomic force microscopy (AFM) and zeta potential analysis. The patients' motor and respiratory functions were evaluated using the revised ALS Functional Rating Scale (ALSFRS-R) and percentage of forced vital capacity (%FVC). Patient survival was also assessed. Erythrocyte surface roughness was significantly smoother in ALS patients, and this parameter was a predictor of faster decline in ALSFRS-R scores. ALS patients exhibited higher erythrocyte stiffness, as indicated by reduced AFM tip penetration depth, which predicted a faster ALSFRS-R score and respiratory subscore decay. A lower negative charge on the erythrocyte membrane was predictor of a faster ALSFRS-R and FVC decline. Additionally, a larger erythrocyte surface area was an independent predictor of lower survival. These changes in morphological and biophysical membrane properties of ALS patients' erythrocytes, lead to increased cell stiffness and morphological variations. We speculate that these changes might precipitate motoneurons dysfunction and accelerate disease progression. Further studies should explore the molecular alterations related to these observations. Our findings may contribute to dissect the complex interplay between respiratory function, tissue hypoxia, progression rate, and survival in ALS.

Electrokinetic properties of healthy and β-thalassemia erythrocyte membranes under in vitro exposure to static magnetic field

Introduction: The current understanding of the biological impacts of a static magnetic field (SMF) is restricted to the direct interactions of the magnetic field with biological membranes. The electrokinetic (zeta) potential is an electrochemical property of erythrocyte surfaces which was negatively charged in physiological media after SMF exposure (0.1‒2.0 T).Methods: The novel data about electrokinetic parameters of the erythrocytes is determined by microelectrophoresis after SMF-exposure in norm and heterozygous β-thalassemia. The methods of light scattering, lipid peroxidation, fluorescence microscopy are used.Results: The electrokinetic potential of erythrocytes in norm is increased after SMF intensities due to enhanced negatively exposed charges on the outer surface of the membrane accompanied by an increase in light scattering where changes in cell morphology are observed. Conversely, a decrease in the zeta potential of β-thalassemia erythrocytes upon SMF-treatment was determined because of the reduction in the surface electrical charge of the membranes, where a significant decrease in light scattering at 1.5 T and 2.0 T was recorded. Exposure to SMF (0.5–2.0 T) was associated with an increase in the malondialdehyde content in erythrocytes. Biophysical studies regarding the influence of SMF on the electrostatic free energy of cells shows an increase in negative values in healthy erythrocytes, which corresponds to the implementation of a spontaneous process. This is also the process in β-thalassemia cells after SMF exposure with lower negative values of free electrostatic energy than erythrocytes in norm.Discussion: The effect of static magnetic field (SMF 0.1–2.0 T) on the electrokinetic and morphological characteristics of erythrocytes in norm and β-thalassemia is determined and correlated with the increase/reduction in surface charge and shrinkage/swelling of the cells, respectively. Lipid peroxidation of healthy and β-thalassemia erythrocytes caused an enhancement of lipid peroxidation because of the higher concentrations of TBARS products in cellular suspension. SMF (0.1‒2.0 T) altered the spontaneous chemical processes with negative values of electrostatic free energy of erythrocytes in norm and β-thalassemia accompanied by a lower FITC-Concanavalin A binding affinity to membrane receptors (SMF 2.0 T). The electrokinetic properties of human erythrocytes in norm and β-thalassemia upon SMF treatment and their interrelationship with the structural-functional state of the membrane were reported. The presented work would have future fundamental applications in biomedicine.

Seasonal changes in blood rheology in little ground squirrels.

The annual cycle of small ground squirrels (Spermophilus pygmaeus) consists of 2 periods: wakefulness (spring-autumn) and hibernation (winter). During the active period, ground squirrels breed (spring), accumulate fat reserves (summer) and prepare for hibernation (autumn). We suppose that the rheological properties of blood and the deformability of erythrocytes can change in different seasons of the animal's wakefulness period to adequately provide tissues with oxygen. The aim of this study was to identify possible adaptive changes in erythrocyte deformability and erythrocyte indices in ground squirrels during their active period. The deformability of erythrocytes was studied by ektacytometry in an osmotic gradient. It was found that in spring, after the arousal of ground squirrels, erythrocytes have the highest deformability (El_max), hydration (O_hyper), water permeability (El_min) and osmotic stability (∆O). In summer, compared with spring, the deformability of erythrocytes decreases, and the average volume of erythrocytes (MCV) also decreases. In autumn, before hibernation, the integral deformability of erythrocytes, their hydration, as well as the range of osmotic stability of erythrocytes increases relative to the summer period. In summer and autumn, in contrast to spring, the average concentration of hemoglobin in the erythrocyte (MCHC) increases. At low shear stress (1 Pa) in summer and autumn, osmoscan becomes a pronounced polymodal form, indicating a change in the viscoelastic properties of ground squirrel erythrocyte membranes. Thus, for the first time, we discovered seasonal variability in the deformability of ground squirrel erythrocytes, which is consistent with the spring-summer activity of animals and preparation for hibernation.

Correlation between sphingomyelin and the membrane stability of mammalian erythrocytes.

Lipid compositions of mammalian erythrocyte membranes are different among species. Therefore, the information on hemolysis from mammalian erythrocytes is useful to understand membrane properties of human erythrocytes. In this work, pressure-induced hemolysis and hypotonic one were examined using erythrocytes of human, sheep, cow, cat, dog, pig, horse, rat, and mouse. Pressure-induced hemolysis was suppressed by membrane sphingomyelin, whereas hypotonic hemolysis decreased upon increment of cell diameter. Mass spectra of erythrocyte membrane lipids demonstrated that sphingomyelin with an acyl chain 24:1 was associated with the suppression of pressure-induced hemolysis. In cow erythrocytes, pressure-induced hemolysis was greatly suppressed and the detachment of cytoskeletal proteins from the membrane under hypotonic conditions was also inhibited. Taken together, these results suggest that sphingomyelin with 24:1 fatty acid plays an important role in the stability of the erythrocyte membrane, perhaps via cholesterol.

REDOX STATUS AND CELL MEMBRANE ALTERATIONS OF CIRCULATING LEUKOCYTES AND ERYTHROCYTES IN ABNORMAL UTERINE BLEEDING

Aim. To analyze the eryptosis degree, the state of cell membranes and redox status of circulating red blood cells and leukocytes in patients with abnormal uterine bleeding and its combination with hypothyroidism. Materials and methods. Patients, 74 women aged 18 to 49 years, were examined, which were divided into 3 groups: group I - women with abnormal uterine bleeding (AUB) (24 patients); group II - with AUB and thyroid pathology (30 patients, of whom 18 women had primary hypothyroidism and 2 - secondary hypothyroidism); group III - control group (20 healthy women, who had never had menstrual irregularities). Eryptosis of circulating erythrocytes was assessed by flow cytometry using annexin V staining and 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) staining. Fluorescent probes O1O (2-(2¢-hydroxy-phenyl)-5-phenyl-1,3-oxazole) and PH7 (2-(2¢-hydroxy-phenyl)-phenanthro[9,10-d]-1,3-oxazole) were used to characterize changes in phospholipid bilayers of circulating erythrocytes and leukocytes. Lysed blood samples were stained with antibodies to CD45, 7-aminoactinomycin D and H2DCFDA to analyze the redox status of circulating viable leukocytes. Results. Annexin V staining revealed eryptosis activation in females with abnormal uterine bleeding combined with hypothyroidism. In addition, in these patients, oxidative stress developed in red blood cells, evidenced by an increase in intracellular reactive oxygen species (ROS) levels. Oxidative stress was accompanied by changes in the physico-chemical properties of erythrocyte membranes, namely a decrease in membrane hydration and an increase in lipid order, which can indicate enhanced lipid peroxidation. These changes were observed in women with abnormal uterine bleeding alone, however, to a lesser extent. In this study, the redox state of leukocytes and phospholipid bilayers of their cell membranes were not affected in the patients from both groups. Conclusions. Abnormal uterine bleeding combined with hypothyroidism is associated with eryptosis activation, oxidative stress development in erythrocytes and changes in the physico-chemical properties of phospholipid bilayer of cell membranes in red blood cells.

Study of the Structural and Mechanical Properties of Erythrocyte Membranes Using Atomic Force Microscopy

Study of the Structural and Mechanical Properties of Erythrocyte Membranes Using Atomic Force Microscopy

Different Types of Constitutive Parameters Red Blood Cell Membrane Based on Machine Learning and FEM

Research on mechanical response of single red blood cells (RBCs) to mechanical stimuli and the complex material properties of erythrocyte membranes is significant. This work proposes a novel procedure that combines nonlinear finite element method and two machine learning algorithms including Two-Way Deepnets and XGboost together with experiments to identify the hyper elastic material parameters of erythrocyte membranes. Finite element models were established to simulate the stretching process of erythrocyte optical tweezers with different constitutive material parameters from three constitutive models. And the results from the finite element analysis were carried out to generate the training sets for the neural networks. In order to validate the predictions in great detail, the finite element response curves based on the three groups of predicted constitutive parameters are compared with the experimental data. The comparison results show that the Two-Way Deepnets model has performed better efficiency and accuracy and that Reduced Polynomial can describe more precisely the hyperelastic properties of the erythrocyte membrane in the range of experimentally obtained characteristics of single RBCs. This research provides new insights into the identification of constitutive parameters of biological cell membranes, which is crucial for the future research on mechanical mechanisms of the biological cells.

The erythrocyte membrane properties of beta thalassaemia heterozygotes and their consequences for Plasmodium falciparum invasion

Malaria parasites such as Plasmodium falciparum have exerted formidable selective pressures on the human genome. Of the human genetic variants associated with malaria protection, beta thalassaemia (a haemoglobinopathy) was the earliest to be associated with malaria prevalence. However, the malaria protective properties of beta thalassaemic erythrocytes remain unclear. Here we studied the mechanics and surface protein expression of beta thalassaemia heterozygous erythrocytes, measured their susceptibility to P. falciparum invasion, and calculated the energy required for merozoites to invade them. We found invasion-relevant differences in beta thalassaemic cells versus matched controls, specifically: elevated membrane tension, reduced bending modulus, and higher levels of expression of the major invasion receptor basigin. However, these differences acted in opposition to each other with respect to their likely impact on invasion, and overall we did not observe beta thalassaemic cells to have lower P. falciparum invasion efficiency for any of the strains tested.

Ultrastructural characteristics of erythrocytes and their relationship with oxygen transport in patients with ischemic heart disease after coronary artery bypass grafting with artificial circulation

Aim. Evaluation of nanostructural and micromechanical characteristics of erythrocytes and their relationship with the parameters of oxygen transport in patients with ischemic heart disease (IHD) after coronary artery bypass grafting (CABG) under artificial circulation (AC).Materials and methods. The study involved 30 men with IHD aged 53 to 67 years with a median of 63 years, who underwent planned CABG with AC at the clinic of the Far Eastern Federal University. Blood sampling from patients was carried out before the AC and one day after it from a venous catheter located in the right atrium. Erythrocytes were scanned using a Bioscope Catalyst atomic force microscope (AFM) (Bruker, USA) in combination with an Axiovert 200 inverted microscope (Zeiss, Germany). The micromechanical properties of cell membranes were investigated with the PFQNM-LC-A-CAL cantilevers. The following were recorded: the diameter of erythrocytes, the height of their side, area, volume, membrane rigidity, strength of its adhesion, Young's modulus, elastic deformation. To assess oxygen transport, the oxygen delivery index (DO2I), consumption (VO2I), and extraction ratio (O2ER) were calculated.Results. In one day after CABG, a decrease in DO2I, VO2I, and O2ER was recorded by 14%, 33%, and 16%, respectively, which indicated a limitation in the gas transport function of the blood. Analysis of the AFM characteristics of erythrocytes showed an increase in their area by 35%, in diameter by 6%, in volume by 19%, and the height of the side by 5 times. At the same time, multidirectional changes in the micromechanical properties of erythrocyte membranes were noted: Young's modulus and stiffness decreased by 3.2 and 2 times, respectively; the adhesion force increased by 2.7 times, and the elastic deformation – by 2.2 times. Correlation analysis showed the presence of reliable relationships between indicators of oxygen transport and biomechanical parameters of erythrocyte membranes.Conclusion. A comprehensive analysis of the nanostructural parameters of erythrocytes and oxygen transport expands the understanding of the pathophysiological mechanisms of postperfusion disorders in patients with coronary artery disease after CABG under conditions of cardiopulmonary bypass.

787P Endotoxicosis and properties of erythrocyte membranes in patients with cervical cancer receiving combination therapy with dendritic cell-based immunotherapy

The efficacy of antitumor treatment depends on the function of proteins and structural components of cells. We studied the effect of immunotherapy with dendritic cell vaccine (DCV) as a part of combination therapy on the functional status of albumin, endogenous intoxication and structural and functional properties of erythrocyte membranes.

SYNDROME OF AUTONOMIC DYSFUNCTION IN CHILDREN OF YOUNG SCHOOL AGE: RISK FACTORS AND STRUCTURAL AND FUNCTIONAL STATE OF ERYTHROCYTE MEMBRANES

Aim. To study the anamnesis and physical and chemical characteristics of erythrocyte membranes in schoolchildren aged 7-11 years to determine the risk of developing autonomic dysfunction syndrome in a particular child. Materials and methods. Clinical, anamnestic and laboratory examination of schoolchildren aged 7-11 years with the syndrome of autonomic dysfunction and practically healthy children was carried out. The physical and chemical properties of erythrocyte membranes were studied by fluorescence spectroscopy. Results. In children with autonomic dysfunction syndrome, the method of fluorescence spectroscopy revealed structural transformations and changes in the functions of erythrocyte membranes of a destabilizing nature. Significant biophysical risk factors for the development of autonomic dysfunction syndrome in children in children of 7-11 years old turned out to be: low calcium-accumulating capacity of membranes, high rates of membrane-bound water and fluidity of the surface layers of the membrane, as well as an increased coefficient of asymmetry of the fluidity of the lipid bilayer. Conclusion. Identification of significant anamnestic and biophysical (at the membrane level) risk factors in a particular child is necessary to include the child in the risk group for psychosomatic diseases for dynamic monitoring and timely implementation of preventive measures.

Membranotropic and biological activities of the membrane fusion peptides from SARS-CoV spike glycoprotein: The importance of the complete internal fusion peptide domain.

Fusion peptides (FP) are prominent hydrophobic segments of viral fusion proteins that play critical roles in viral entry. FPs interact with and insert into the host lipid membranes, triggering conformational changes in the viral protein that leads to the viral-cell fusion. Multiple membrane-active domains from the severe acute respiratory syndrome (SARS) coronavirus (CoV) spike protein have been reported to act as the functional fusion peptide such as the peptide sequence located between the S1/S2 and S2’ cleavage sites (FP1), the S2’-adjacent fusion peptide domain (FP2), and the internal FP sequence (cIFP). Using a combined biophysical approach, we demonstrated that the α-helical coiled-coil-forming internal cIFP displayed the highest membrane fusion and permeabilizing activities along with membrane ordering effect in phosphatidylcholine (PC)/phosphatidylglycerol (PG) unilamellar vesicles compared to the other two N-proximal fusion peptide counterparts. While the FP1 sequence displayed intermediate membranotropic activities, the well-conserved FP2 peptide was substantially less effective in promoting fusion, leakage, and membrane ordering in PC/PG model membranes. Furthermore, Ca2+ did not enhance the FP2-induced lipid mixing activity in PC/phosphatidylserine/cholesterol lipid membranes, despite its strong erythrocyte membrane perturbation. Nonetheless, we found that the three putative SARS-CoV membrane-active fusion peptide sequences here studied altered the physical properties of model and erythrocyte membranes to different extents. The importance of the distinct membranotropic and biological activities of all SARS-CoV fusion peptide domains and the pronounced effect of the internal fusion peptide sequence to the whole spike-mediated membrane fusion process are discussed.

Alterations in the Plasma and Red Blood Cell Properties in Patients with Varicose Vein: A Pilot Study.

The varicose vein results from the inefficient functioning of the valves in the lower limb veins, making the blood flow slow down and leading to blood stasis and hypoxia. This type of vein dysfunction might be a result of the development of oxidative stress. We compared oxidative stress markers in the plasma and erythrocytes obtained from peripheral veins and varicose veins in the same patients (glutathione, nonenzymatic antioxidant capacity (NEAC), catalase (CAT) and acetylcholinesterase (AChE) activity, thiols, thiobarbituric acid-reactive substance (TBARS), and protein carbonyls). We found a decrease in NEAC in the plasma obtained from the varicose veins compared to the peripheral veins. We detected a decrease in thiols in the plasma, hemolysate, and plasma membranes and increase in protein carbonyl compounds and TBARS levels in the varicose veins. These changes were accompanied by a decrease in CAT and AChE activity. For the first time, our results show changes in the plasma, erythrocyte membrane, and hemolysate protein properties in varicose vein blood in contrast to the plasma and erythrocytes in peripheral vein blood from the same patients. The increased oxidative stress accompanying varicose vein disease might result from the local inefficiency of the antioxidant defense system.

Physical and Chemical Properties of Erythrocyte Membranes in Interaction with Polyene Antibiotics in the Field of Ultrasonic Waves

Physical and Chemical Properties of Erythrocyte Membranes in Interaction with Polyene Antibiotics in the Field of Ultrasonic Waves

Improved pharmacokinetic and biodistribution of 5-fluorouracil loaded biomimetic nanoerythrocytes decorated nanocarriers for liver cancer treatment

Nanoerythrocytes membrane (NEs) has recently been used to improve pharmacokinetics and biodistribution for successful drug therapy. NEs intended to enhance the drug targeting due to immune evasion and long circulation. In this work, NEs could serve as efficient 5- fluorouracil (5-FU) carriers to target liver cells. NEs decorated 5-FU-loaded chitosan coated-poly (lactide-co-glycolic acid) nanoparticles (5-FU-C-NPs-NEs), chitosomes (5-FU-C-LPs-NEs) and 5-FU-NEs were prepared by hypotonic lysis and extrusion procedures. Moreover, 5-FU loaded-chitosan coated 5-FU-NPs (5-FU-C-NPs) and chitosomes (5-FU-C-LPs) for the compared issues were prepared. They were characterized in terms of particle size, encapsulation efficiency (EE), membrane protein content, phosphatidylserine exposure, surface morphology, and in vitro release profiles. Also, their cytotoxic efficacy was determined. Furthermore, pharmacokinetics and biodistribution studies were investigated for optimized formulation. The results revealed that 5-FU-C-NPs-NEs have narrow particle size distribution, desirable EE%, and retained the erythrocyte membrane properties as confirmed by polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, it displayed a sustained release profile up to 72 h of 5-FU-C-NPs-NEs compared to other formulations. In comparison to 5-FU solution and 5-FU-C-NPs, 5-FU-C-NPs-NEs extended the drug release time in vivo with highly uptake by the liver. These results suggest that the 5-FU-C-NPs-NEs could be used to deliver 5-FU and enhance its targetability to liver cancer.

Structural and functional indicators of erythrocyte membranes in gastric cancer patients with different histotypes of the tumor and stages of the malignant process

The purpose was to study the structural and functional parameters of erythrocyte membranes in the blood of patients with gastric cancer (GC) – adenocarcinoma, depending on its grade, signet ring cell carcinoma (SRCC), and combined gastric lesions (CGL). Materials and methods . The membrane fluidity in the area of the lipid bilayer and protein-lipid contacts, the polarity of the lipid bilayer and the immersion of proteins in the lipid matrix of the membrane in red blood cells were evaluated by fluorimetry using the hydrophobic pyrene-based probe. The study included 86 patients with GC divided into six groups: well- and moderately-differentiated adenocarcinoma (G1-2); poorly-differentiated adenocarcinoma (G3); SRCC; CGL and two groups of patients with a component of undifferentiated cancer: G4 + SRCC and G4 + G2-3. The results of the study were also analyzed in patients with serosal invasion and the spread to adjacent structures (T4 according to the TNM classification of malignant tumors) and in patients with stage IV disease. Results. In all groups of GC patients, an increase in the membrane fluidity was observed. It was more pronounced in the zone of protein-lipid contacts, but it was also observed in the lipid bilayer. The membrane fluidity increased together with the grade of adenocarcinoma and was maximal when there were undifferentiated cells in stomach tumors, reaching 93.8% in the zone of protein-lipid contacts and 54.1% in the lipid bilayer, compared with healthy people (20 donors). An increase in the polarity of the lipid phase was also observed; it was most pronounced (by 7–8%, p = 0.002–0.003) in adenocarcinoma patients with undifferentiated cells and with stage IV disease. A change in the immersion of proteins in the lipid matrix of erythrocytes was less characteristic of GC, compared with other cancers (breast, lung tumors, gynecological oncopathology, etc.). Conclusions. Changes in the structural and functional properties of erythrocyte membranes reflect the state of the disease in patients with gastric cancer and may be important for predicting the course of the disease and the success of treatment.

ASSESSMENT OF CHANGES IN THE LIPID COMPOSITION OF BLOOD PLASMA AND ERYTHROCYTE MEMBRANES IN STUDENTS UNDER STUDY LOAD AND THEIR PREVENTION

Introduction. The content of low and high-density lipoproteins, the level of total cholesterol, and the fatty acids composition of blood plasma and erythrocyte membranes were studied in first-year university students. The prevention of stress disorders was carried out with the functional food product “Biolad-Kalina” marmalade (TU 9128-152-02067936-2006) contained 100 mg of a complex of polyphenolic compounds per 100 g of the product, accounting for a therapeutic dose for polyphenol preparations. Material and methods. A group of 10 male students aged 18-20 years studying in the 1st year of full-time study (2nd semester after admission to the university) was examined. The 1st group (control) included 20 healthy male donors; in the 2nd group - 10 male students before a biochemical blood test, the 3rd group - 10 male students of the 2nd group, after a biochemical blood test, invited to take daily for 6 weeks in the morning, 100 g of marmalade “Biolad-Kalina”. Results. The effect of the study load (stress) was shown to be accompanied by the increase in low-density lipoproteins in plasma, the concentration of total cholesterol, total lipids and decrease in the content of total phospholipids, which is typical for dyslipidemia. In blood plasma and erythrocyte membranes, there was an increase in the content of saturated fatty acids (myristic, palmitic) and a decrease in the amount of polyunsaturated fatty acids of n-6 (arachidonic) and n-3 (eicosapentaenoic, docosahexaenoic) families, which causes changes in the physical and chemical properties of erythrocyte membranes, permeability, and lability. Changes in the ratio of fatty acids in the lipid pattern of erythrocyte membranes indicate the presence of destructive processes under the influence of stress. A prophylactic effect of the functional food product of marmalade “Biolad-Kalina” on the studied biochemical indices has been estimated. There was shown its effectiveness in the restoration of lipid metabolism in blood and erythrocyte membranes due to presence in it of a wide range of polyphenolic compounds.

Electrochemical Impedance Characterization of Blood Cell Suspensions-Part 2: Three-Phase Systems With Single-Shelled Particles.

The analyses presented in Part 1 are expanded to three-phase composite materials. The theory developed in Part 1 is used for analytical and numerical calculations of dielectric spectra. In this study, three-phase systems with single-shelled particles were considered. The disordered particle distribution, aligned orientation of particles, and particles placed in different lattice structures are studied. It is shown that both two-phase and three-phase composites exhibit β-dispersion, while three-phase composites additionally exhibit δ-dispersion. This is the fundamental difference in the spectra for two- and three-phase materials. In the case of aligned orientation, the effective permittivity in the direction perpendicular to the spheroid plane exhibits a maximum at a volume fraction of approximately 0.5. Both two- and three-phase materials display this behavior. This may be of interest for the development of new metamaterials. The dielectric properties of composite materials with random distribution and periodic arrangement of particles differ significantly. The dielectric spectrum of erythrocyte suspension in plasma was measured by means of electrochemical impedance spectroscopy. The measurement system consisted of a small chamber with two planar electrodes placed at the bottom and an impedance analyzer. The dielectric properties of erythrocyte cytoplasm and membrane were numerically determined based on experimental data. The measurement of the dielectric properties of whole blood and blood components is very promising for various medical applications.

Hybrid Erythrocyte Liposomes: Functionalized Red Blood Cell Membranes for Molecule Encapsulation.

The modification of erythrocyte membrane properties provides a new tool towards improved drug delivery and biomedical applications. The fabrication of hybrid erythrocyte liposomes is presented by doping red blood cell membranes with synthetic lipid molecules of different classes (PC, PS, PG) and different degrees of saturation (14:0, 16:0-18:1). The respective solubility limits are determined, and material properties of the hybrid liposomes are studied by a combination of X-ray diffraction, epi-fluorescent microscopy, dynamic light scattering (DLS), Zeta potential, UV-vis spectroscopy, and Molecular Dynamics (MD) simulations. Membrane thickness and lipid orientation can be tuned through the addition of phosphatidylcholine lipids. The hybrid membranes can be fluorescently labelled by incorporating Texas-red DHPE, and their charge modified by incorporating phosphatidylserine and phosphatidylglycerol. By using fluorescein labeled dextran as an example, it is demonstrated that small molecules can be encapsulated into these hybrid liposomes.