A Comparative Study Between Micro and Millimeter Impedance Sensor Designs for Type-2 Diabetes Detection

Novel single-cell functional analysis of red blood cells using laser tweezers Raman spectroscopy: Application for sickle cell disease

Introduction: Red blood cell(RBC), which passes through capillaries and exchanges O2 and CO2 with surrounding tissues, plays a very important in the blood circulation in the human body. Imbalance in blood circulation could lead to various cardiovascular related diseases such as high blood pressure, arteriosclerosis, diabetes, and stroke.[1] This is closely related to RBC aggregation. Negatively charged RBC membrane arranges a compact layer of positive ions around the membrane by electrical attraction with cations in plasma.The rearranged ions layer in plasma forms zeta potential with compact layer. When the electrostatic interaction between RBCs, i.e., zeta potential increases, RBC aggregation is improved. It is known that zeta potential depends on electronegativity of the RBC membrane, the dielectric constant of the medium and ionic strength [2]. Since pulsed magnetic field (PMF) influences human physiology, many clinical studies demonstrated the effect of PMF for wound healing, reducing pain, increasing angiogenesis, as well as improving blood circulation.[3-5] In this study, we have tried to elucidate the effect of PMF on RBC aggregation by indirectly observing zeta potential using negatively-charged magnetic beads(MB). Our hypothesis is that the increase of negative charges on RBC membrane results in the increase of cations in the compact layer, thus the increase of the zeta potential. As a result, the number of MB attached to the RBC increases, as the binding force between MB and compact layer increases.Experimental Method: Blood needed for experiment was obtained from Korean Red Cross after reviewing IRB exemption in Sangji University Bioethics Committee. Whole blood of 6 ml was centrifuged at 3000 rpm for 5 min in 4 oC for separating RBCs and plasma. MB used this experiment has diameter 1 μm with OH- groups (SiMAG-Silanol, Chemicell). To clearly see the MB attached to RBCs and, in addition, to avoid blood clots caused by proteins in plasma, RBC suspension of hematocrit (Ht) of 10% was prepared using PBS(phosphate buffer saline). The amount of MB added to RBC suspension was 0.5 mg. RBCs were also oxidative stressed with tBHP(Tert-Butyl hydroperoxide) in 0.4 mM at 37 oCincubator for 30 min, in order to confirm the change of RBCs membrane charge due to oxidative stress under PMF stimulus. In oxidative stressed RBCs, hemoglobin(Fe2+) is altered to methemoglobin(Fe3+) because of loss an electron, thereby, electronegativity of RBC membrane will be changed.[6] Each sample was exposed to PMF for 3 min. Our PMF stimulator system consisted of single layered coil of 10 turns with an elliptical shape of 12.0 x 4.5 cm. The maximum intensity is 0.27 T at a transition time of 0.102 ms, with pulse intervals of 1 Hz. The numbers of RBC attached MB were compared with control group and PMF treatment group. Only RBCs with a distance of about 1 μm between the MB and the surface of RBC were counted using hemocytometer.Results and Discussion: Fig.1. shows the numbers of RBCs according to the number of attached MB in the control and PMF treatment group. The numbers of RBCs attached MB increased after PMF treatment. The more the number of MBs attached to RBCs, the thicker the compact layer surrounding RBC membranes. This phenomenon might be inferred due to an increase of zeta potential, thereby, increase of negative charges on the RBC membrane. Thus, it can be interpreted that MB having hydroxide OH- group are more attached to RBCs via binding force between MB and compact layer. Also the numbers of MB in the group treated tBHP and the group exposed to PMF after tBHP treatment (tBHP+PMF) were compared in Fig.2. Although the number of MB attached to RBCs was 1~2 in tBHP group, after PMF stimulus, i.e. in tBHP+PMF group it appears the number of MB attached to RBCs increased up to 3~4. This might be explained that PMF affects the increase of RBC membrane charge on not only normal RBCs but also oxidative stressed RBCs. Therefore, it can be deduced that high instantaneous flux change of PMF improves the aggregation of RBCs by increasing the zeta potential, due to the increase of the membrane charge. **

Oral Administration of FT-4202, an Allosteric Activator of Pyruvate Kinase-R, Has Potent Anti-Sickling Effects in a Sickle Cell Anemia (SCA) Mouse Model, Resulting in Improved RBC Survival and Hemoglobin Levels

Counting morphologically normal cells in human red blood cells (RBCs) is extremely beneficial in the health care field. We propose a three-dimensional (3-D) classification method of automatically determining the morphologically normal RBCs in the phase image of multiple human RBCs that are obtained by off-axis digital holographic microscopy (DHM). The RBC holograms are first recorded by DHM, and then the phase images of multiple RBCs are reconstructed by a computational numerical algorithm. To design the classifier, the three typical RBC shapes, which are stomatocyte, discocyte, and echinocyte, are used for training and testing. Nonmain or abnormal RBC shapes different from the three normal shapes are defined as the fourth category. Ten features, including projected surface area, average phase value, mean corpuscular hemoglobin, perimeter, mean corpuscular hemoglobin surface density, circularity, mean phase of center part, sphericity coefficient, elongation, and pallor, are extracted from each RBC after segmenting the reconstructed phase images by using a watershed transform algorithm. Moreover, four additional properties, such as projected surface area, perimeter, average phase value, and elongation, are measured from the inner part of each cell, which can give significant information beyond the previous 10 features for the separation of the RBC groups; these are verified in the experiment by the statistical method of Hotelling's T-quare test. We also apply the principal component analysis algorithm to reduce the dimension number of variables and establish the Gaussian mixture densities using the projected data with the first eight principal components. Consequently, the Gaussian mixtures are used to design the discriminant functions based on Bayesian decision theory. To improve the performance of the Bayes classifier and the accuracy of estimation of its error rate, the leaving-one-out technique is applied. Experimental results show that the proposed method can yield good results for calculating the percentage of each typical normal RBC shape in a reconstructed phase image of multiple RBCs that will be favorable to the analysis of RBC-related diseases. In addition, we show that the discrimination performance for the counting of normal shapes of RBCs can be improved by using 3-D features of an RBC.

Impaired Erythrocyte Methemoglobin Reduction in Sickle Cell Disease: Dependence of Methemoglobin Reduction on Reduced Nicotinamide Adenine Dinucleotide Content

In order to assess how the number of cell divisions influences the red blood cell (RBC) content of proteins other than hemoglobin, we measured the activity of two age-independent glycolytic enzymes in macrocytic, normal, and microcytic RBCs. The enzymes measured were phosphoglycerate kinase (PGK) and lactic dehydrogenase (LDH). In macrocytes, both PGK and LDH activity/10(10) RBCs were increased 1.6-fold over normal RBCs. In microcytes, however, the activity of these enzymes was identical to that seen in normal RBCs.

Sodium transport in red cells of patients with acute viral hepatitis

“Lysosomal” enzyme activities in red blood cells of normal individuals and patients with homozygous β-thalassaemia

Copper (Cu) nanoparticles (NPs) were prepared by sol–gel process, and superconducting (Cu0.5Tl0.5)Ba2Ca2Cu3O10−δ {(CuTl)-1223} phase was synthesized by conventional solid-state reaction. The desired (Cu)x/(CuTl)-1223, x = 0–4.0 wt% composites, were obtained by adding Cu NPs in superconducting (CuTl)-1223 phase. These composites were characterized by X-ray diffraction, DC-resistivity versus temperature (R–T) and AC conduction measurements. The tetragonal crystal structure with P4/mmm space group of the host superconducting (CuTl)-1223 phase remained dominant after the addition of Cu NPs. The zero-resistivity critical temperature Tc(0) (K) was increased, and normal state resistivity was decreased after addition of Cu NPs in CuTl-1223 phase. The frequency- and temperature-dependent AC conduction properties of (Cu)x/(CuTl)-1223 composites were explored via dielectric, impedance and electric modulus measurements. The dielectric constant (ɛr/, ɛr//) and loss tangent (tanδ) were suppressed, while AC conductivity (σac) was improved with the addition of Cu NPs in (CuTl)-1223 phase. Comparatively, the capacitance associated with grain boundaries regions was found to be greater than the capacitance associated with grain regions. The capacitive behavior of the grain boundaries was decreased, while that of the grains was increased with increasing operating temperature for all these composite samples. The shifting of peaks in imaginary part of the electric modulus (M//) versus frequency (f) spectra toward lower frequency regime with increasing Cu NPs contents in superconducting (CuTl)-1223 phase is witnessed for the existence of non-Debye relaxation in the material.

A series of organic‐inorganic hybrid of polyaniline (PANI)/copper‐alumina (Cu‐Al2O3) nanocomposites were prepared by in situ polymerization technique. The structural, morphological and thermal properties of PANI with different contents of nano Cu‐Al2O3 were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction analysis (XRD), scanning electron microscopy (SEM), high‐resolution transmission electron microscope (HR‐TEM), differential scanning calorimetry (DSC), and thermogravimteric analysis. The dielectric constant, dielectric loss and the AC conductivity were measured using a dielectric analyzer in a frequency ranging from 100 Hz to 1 MHz. Also, current (I)‐voltage (V) characteristics and gas sensing performance of the composites were studied in detail. The FTIR spectra of composite exhibited the IR band of nanoparticles in the macromolecular chain of PANI. The XRD pattern showed the systematic arrangement of Cu‐Al2O3 particles in the molecular structure of polyaniline. The SEM and TEM images indicated that the nanoparticles were sheathed by polyaniline. DSC results showed that incorporation of Cu‐Al2O3 accelerated the glass transition temperature of PANI. TG analysis demonstrated the enhancement in thermal stability of PANI/Cu‐Al2O3 nanocomposite relative to the base polymer. Conductivity studies showed that both AC and DC conductivity, dielectric constant, and dielectric loss increased with increase in the concentration of nanoparticles up to 5 wt%. Similarly, the ammonia gas sensing behavior of nanocomposites was also improved by the addition of Cu‐Al2O3 nanoparticles.

Dielectric properties and ac conductivity of TlSbTe2 thin films

Vesiculation of mature red blood cells (RBCs) contributes to removal of defective patches of the erythrocyte membrane. In blood disorders, which are related to defects in proteins of the RBC membrane, vesiculation of the plasma membrane is intensified. Several hypotheses have been proposed to explain RBC vesiculation but the exact underlying mechanisms and what determines the sizes of the vesicles are still not completely understood. In this work, we apply a two-component coarse-grained molecular dynamics RBC membrane model to study how RBC vesiculation is controlled by the membrane spontaneous curvature and by lateral compression of the membrane. Our simulation results show that the formation of small homogeneous vesicles with a diameter less than 40 nm can be attributed to a large spontaneous curvature of membrane domains. On the other hand, compression on the membrane can cause the formation of vesicles with heterogeneous composition and with sizes comparable with the size of the cytoskeleton corral. When spontaneous curvature and lateral compression are simultaneously considered, the compression on the membrane tends to facilitate formation of vesicles originating from curved membrane domains. We also simulate vesiculation of RBCs with membrane defects connected to hereditary elliptocytosis (HE) and to hereditary spherocytosis (HS). When the vertical connectivity between the lipid bilayer and the membrane skeleton is elevated, as in normal RBCs, multiple vesicles are shed from the compressed membrane with diameters similar to the cytoskeleton corral size. In HS RBCs, where the connectivity between the lipid bilayer and the cytoskeleton is reduced, larger-size vesicles are released under the same compression ratio as in normal RBCs. Lastly, we find that vesicles released from HE RBCs can contain cytoskeletal filaments due to fragmentation of the membrane skeleton while vesicles released from the HS RBCs are depleted of cytoskeletal filaments.

Dielectric properties and AC conductivity studies of novel NR/PVA full-interpenetrating polymer networks

Green chemistry approach for the synthesis of CrxCu1-xO nanoparticles: An investigation of the structural and dielectric properties

Photoacoustic (PA) field calculations using a Green’s function approach is presented. The method has been applied to predict PA spectra generated by normal (discocyte) and pathological (stomatocyte) red blood cells (RBCs). The contours of normal and pathological RBCs were generated by employing a popular parametric model and accordingly, fitted with the Legendre polynomial expansions for surface parametrization. The first frequency minimum of theoretical PA spectrum approximately appears at 607 MHz for a discocyte and 410 MHz for a stomatocyte when computed from the direction of symmetry axis. The same feature occurs nearly at 247 and 331 MHz, respectively, for those particles when measured along the perpendicular direction. The average experimental spectrum for normal RBCs is found to be flat over a bandwidth of 150-500 MHz when measured along the direction of symmetry axis. For spherical RBCs, both the theoretical and experimental spectra demonstrate negative slope over a bandwidth of 250-500 MHz. Using the Green’s function method discussed, it may be possible to rapidly characterize cellular morphology from single-particle PA spectra.