A Disposable Blood-on-a-Chip for Simultaneous Measurement of Multiple Biophysical Properties

Biophysical properties are widely used to detect pathophysiological processes of vascular diseases or clinical states. For early detection of cardiovascular diseases, it is necessary to simultaneously measure multiple biophysical properties in a microfluidic environment. However, a microfluidic-based technique for measuring multiple biophysical properties has not been demonstrated. In this study, a simple measurement method was suggested to quantify three biophysical properties of blood, including red blood cell (RBC) deformability, RBC aggregation, and hematocrit. To demonstrate the suggested method, a microfluidic device was constructed, being composed of a big-sized channel (BC), a parallel micropillar (MP), a main channel, a branch channel, inlet, and outlets. By operating a single syringe pump, blood was supplied into the inlet of the microfluidic device, at a periodic on-off profile (i.e., period = 240 s). The RBC deformability index (DI) was obtained by analyzing the averaged blood velocity in the branch channel. Additionally, the RBC aggregation index (AIN) and the hematocrit index (HiBC) were measured by analyzing the image intensity of blood flows in the MP and the BC, respectively. The corresponding contributions of three influencing factors, including the turn-on time (Ton), the amplitude of blood flow rate (Q0), and the hematocrit (Hct) on the biophysical indices (DI, AIN, and HiBC) were evaluated quantitatively. As the three biophysical indices varied significantly with respect to the three factors, the following conditions (i.e., Ton = 210 s, Q0 = 1 mL/h, and Hct = 50%) were maintained for consistent measurement of biophysical properties. The proposed method was employed to detect variations of biophysical properties depending on the concentrations of autologous plasma, homogeneous hardened RBCs, and heterogeneous hardened RBCs. Based on the observations, the proposed method exhibited significant differences in biophysical properties depending on base solutions, homogeneous hardened RBCs (i.e., all RBCs fixed with the same concentration of glutaraldehyde solution), and heterogeneous hardened RBCs (i.e., partially mixed with normal RBCs and homogeneous hardened RBCs). Additionally, the suggested indices (i.e., DI, AIN, and HiBC) were effectively employed to quantify three biophysical properties, including RBC deformability, RBC aggregation, and hematocrit.

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Microfluidic-Based Technique for Measuring RBC Aggregation and Blood Viscosity in a Continuous and Simultaneous Fashion

Micromachines ◽

10.3390/mi9090467 ◽

2018 ◽

Vol 9 (9) ◽

pp. 467 ◽

Cited By ~ 8

Author(s):

Yang Kang

Keyword(s):

Blood Flow ◽

Blood Viscosity ◽

Blood Flow Rate ◽

Aggregation Index ◽

Simple Method ◽

Blood Flows ◽

Wide Channel ◽

Rbc Aggregation ◽

The Right

Hemorheological properties such as viscosity, deformability, and aggregation have been employed to monitor or screen patients with cardiovascular diseases. To effectively evaluate blood circulating within an in vitro closed circuit, it is important to quantify its hemorheological properties consistently and accurately. A simple method for measuring red blood cell (RBC) aggregation and blood viscosity is proposed for analyzing blood flow in a microfluidic device, especially in a continuous and simultaneous fashion. To measure RBC aggregation, blood flows through three channels: the left wide channel, the narrow channel and the right wide channel sequentially. After quantifying the image intensity of RBCs aggregated in the left channel (<IRA>) and the RBCs disaggregated in the right channel (<IRD>), the RBC aggregation index (AIPM) is obtained by dividing <IRA> by <IRD>. Simultaneously, based on a modified parallel flow method, blood viscosity is obtained by detecting the interface between two fluids in the right wide channel. RBC aggregation and blood viscosity were first evaluated under constant and pulsatile blood flows. AIPM varies significantly with respect to blood flow rate (for both its amplitude and period) and the concentration of the dextran solution used. According to our quantitative comparison between the proposed aggregation index (AIPM) and the conventional aggregation index (AICM), it is found that AIPM provides consistent results. Finally, the suggested method is employed to obtain the RBC aggregation and blood viscosity of blood circulating within an in vitro fluidic circuit. The experimental results lead to the conclusion that the proposed method can be successfully used to measure RBC aggregation and blood viscosity, especially in a continuous and simultaneous fashion.

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Abnormal Red Cell Deformability and Aggregation in Sickle Cell Trait

Blood ◽

10.1182/blood.v120.21.1001.1001 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1001-1001

Author(s):

Jon Detterich ◽

Adam M Bush ◽

Roberta Miyeko Kato ◽

Rose Wenby ◽

Thomas D. Coates ◽

...

Keyword(s):

Blood Flow ◽

Blood Viscosity ◽

Whole Blood ◽

Red Cell ◽

Cell Deformability ◽

Autologous Plasma ◽

Red Cell Deformability ◽

Whole Blood Viscosity ◽

Rbc Aggregation ◽

Rbc Deformability

Abstract Abstract 1001 Introduction: SCT occurs in 8% of African Americans and is not commonly associated with clinical disease. Nonetheless, the United States Armed Forces has reported that SCT conveys a 30-fold risk of sudden cardiac arrest and a 200-fold risk from exertional rhabdomyolysis. In fact, rhabdomyolysis in athletes with SCT has been the principal cause of death in NCAA football players in the last decade, leading to recently mandated SCT testing in all Division-1 players. In SCT, RBC sickle only under extreme conditions and with slow kinetics. Therefore, rhabdomyolysis most likely occurs in SCT when a “perfect storm” of factors converges to critically imbalance oxygen supply and demand in muscles. We hypothesize that in SCT subjects, abnormal RBC rheology, particularly aggregation and deformability, play an important role in abnormal muscle blood flow supply and distribution to exercising muscle. To test this hypothesis, we examined whole blood viscosity, RBC aggregation, and RBC deformability in 11 SCT and 10 control subjects prior to and following maximum handgrip exercise. Methods: Maximum voluntary contraction (MVC) was assessed by handgrip dynamometer in the dominant arm. Baseline blood was collected for CBC, whole blood viscosity, RBC aggregation, and RBC deformability. Patients then maintained 60% MVC exercise until exhaustion. Following 8 minutes of recovery, a venous blood gas and blood for repeat viscosity assessments was collected from the antecubital fossa of the exercising limb. Whole blood viscosity over a shear rate range of 1–1, 000 1/s was determined by an automated tube viscometer, RBC deformability from 0.5–50 Pa via laser ektacytometry (LORCA) and RBC aggregation in both autologous plasma and 3% dextran 70 kDa using an automated cone-place aggregometer (Myrenne). Aggregation measurements included extent at stasis (M), strength of aggregation (GT min) and kinetics (T ½). Results: Baseline CBC and aggregation values are summarized in Table 1. Both static RBC aggregation in plasma and RBC aggregation in dextran (aggregability) were significantly increased in SCT (Table 1). The rate of aggregation formation trended higher in SCT but the strength of aggregation was not different between the two groups. In SCT subjects, red cell deformability was impaired at low shear stress but greater than controls at higher shear stress (Figure 1). Red cell deformability was completely independent of oxygenation status states in both SCT and control subjects. Whole blood viscosity did not different between the two groups whether oxygenated or deoxygenated and prior to or following handgrip exercise. Discussion: Three important hemorheological differences were observed for SCT subjects versus controls: a) RBC deformability was below control at low stress levels yet greater than control at higher stress; b) The extent of RBC aggregation in autologous plasma was about 40% greater; c) The extent of RBC aggregation for washed RBC re-suspended in an aggregating medium (i.e., 3% dextran 70 kDa) was about 30% higher. RBC deformability is a major determinant of in vivo blood flow dynamics, especially in the microcirculation; decreased deformability adversely affects tissue perfusion. RBC aggregation is also an important determinant since it affects both resistance to blood flow and RBC distribution in a vascular bed (e.g., plasma skimming). The finding of greater aggregability (i.e., higher aggregation in the defined dextran medium) indicates that RBC in SCT have an altered membrane surface in which the penetration of this polymer into the glycocalyx is abnormal. The combined effects of these three rheological parameters is likely to impair in vivo blood flow in SCT, perhaps to a degree resulting in pathophysiological changes of the cardiovascular system. Disclosures: Coates: Novartis: Speakers Bureau; Apopharma: Consultancy. Wood:Ferrokin Biosciences: Consultancy; Shire: Consultancy; Apotex: Consultancy, Honoraria; Novartis: Honoraria, Research Funding.

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Microfluidic-Based Biosensor for Sequential Measurement of Blood Pressure and RBC Aggregation Over Continuously Varying Blood Flows

Micromachines ◽

10.3390/mi10090577 ◽

2019 ◽

Vol 10 (9) ◽

pp. 577 ◽

Cited By ~ 4

Author(s):

Yang Jun Kang

Keyword(s):

Blood Flow ◽

Shear Rate ◽

Microfluidic Device ◽

Blood Viscosity ◽

Blood Samples ◽

Image Intensity ◽

Blood Flows ◽

Pressure Index ◽

Sequential Measurement ◽

Rbc Aggregation

Aggregation of red blood cells (RBCs) varies substantially depending on changes of several factors such as hematocrit, membrane deformability, and plasma proteins. Among these factors, hematocrit has a strong influence on the aggregation of RBCs. Thus, while measuring RBCs aggregation, it is necessary to monitor hematocrit or, additionally, the effect of hematocrit (i.e., blood viscosity or pressure). In this study, the sequential measurement method of pressure and RBC aggregation is proposed by quantifying blood flow (i.e., velocity and image intensity) through a microfluidic device, in which an air-compressed syringe (ACS) is used to control the sample injection. The microfluidic device used is composed of two channels (pressure channel (PC), and blood channel (BC)), an inlet, and an outlet. A single ACS (i.e., air suction = 0.4 mL, blood suction = 0.4 mL, and air compression = 0.3 mL) is employed to supply blood into the microfluidic channel. At an initial time (t < 10 s), the pressure index (PI) is evaluated by analyzing the intensity of microscopy images of blood samples collected inside PC. During blood delivery with ACS, shear rates of blood flows vary continuously over time. After a certain amount of time has elapsed (t > 30 s), two RBC aggregation indices (i.e., SEAI: without information on shear rate, and erythrocyte aggregation index (EAI): with information on shear rate) are quantified by analyzing the image intensity and velocity field of blood flow in BC. According to experimental results, PI depends significantly on the characteristics of the blood samples (i.e., hematocrit or base solutions) and can be used effectively as an alternative to blood viscosity. In addition, SEAI and EAI also depend significantly on the degree of RBC aggregation. In conclusion, on the basis of three indices (two RBC aggregation indices and pressure index), the proposed method is capable of measuring RBCs aggregation consistently using a microfluidic device.

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Microfluidic-based measurement of RBC aggregation and the ESR using a driving syringe system

Analytical Methods ◽

10.1039/c7ay02719b ◽

2018 ◽

Vol 10 (16) ◽

pp. 1805-1816 ◽

Cited By ~ 7

Author(s):

Yang Jun Kang

Keyword(s):

Blood Cell ◽

Erythrocyte Sedimentation Rate ◽

Microfluidic Device ◽

Sedimentation Rate ◽

Red Blood Cell ◽

Aggregation Index ◽

Erythrocyte Sedimentation ◽

System P ◽

Rbc Aggregation

The erythrocyte sedimentation rate (ESR) and red blood cell (RBC) aggregation in a driving syringe are simultaneously measured by quantifying blood press index (Ipress) and RBC aggregation index (IRA) in a microfluidic device.

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Behaviour of Human Erythrocyte Aggregation in Presence of Autologous Lipoproteins

Biochemistry Research International ◽

10.1155/2012/261736 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 4

Author(s):

C. Saldanha ◽

J. Loureiro ◽

C. Moreira ◽

J. Martins e Silva

Keyword(s):

Particle Number ◽

Plasma Osmolality ◽

Erythrocyte Aggregation ◽

Lipoprotein Subfractions ◽

Autologous Plasma ◽

Aggregation Index ◽

Number Range ◽

Human Blood Samples ◽

Range Of Values

The aim of this work was to evaluatein vitrothe effect of autologous plasma lipoprotein subfractions on erythrocyte tendency to aggregate. Aliquots of human blood samples were enriched or not (control) with their own HDL-C, LDL-C, or VLDL-C fractions obtained from the same batch by density gradient ultracentrifugation. Plasma osmolality and erythrocyte aggregation index (EAI) were determined. Blood aliquots enriched with LDL-C and HDL-C showed significant higher EAI than untreated aliquots, whereas enrichment with VLDL-C does not induce significant EAI changes. For the same range of lipoprotein concentrations expressed as percentage of osmolality variation, the EAI variation was positive and higher in presence of HDL-C than upon enrichment with LDL-C (P<0.01). Particle size, up to LDL diameter values, seems to reinforce erythrocyte tendency to aggregate at the same plasma osmolality (particle number) range of values.

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Continuous and simultaneous measurement of the biophysical properties of blood in a microfluidic environment

The Analyst ◽

10.1039/c6an01593j ◽

2016 ◽

Vol 141 (24) ◽

pp. 6583-6597 ◽

Cited By ~ 18

Author(s):

Yang Jun Kang

Keyword(s):

Blood Viscosity ◽

Simultaneous Measurement ◽

Measurement Method ◽

Biophysical Properties ◽

Rbc Aggregation

A new measurement method is proposed to quantify blood viscosity, blood viscoelasticity, and RBC aggregation, in a continuous and simultaneous fashion.

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A Comparative Study of the Main Pulmonary Artery and Ascending Aorta Biomechanical Behavior

ASME 2011 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2011-53932 ◽

2011 ◽

Author(s):

Bahar Fata ◽

Elena Galdi ◽

Michael S. Sacks

Keyword(s):

Pulmonary Artery ◽

Mechanical Behavior ◽

Ductus Arteriosus ◽

Main Pulmonary Artery ◽

Blood Flow Rate ◽

Biomechanical Properties ◽

Ascending Aorta ◽

External Diameter ◽

Blood Flows ◽

Biomechanical Behavior

During the prenatal period a state of physiologic pulmonary hypertension exists due to the equalization of pressures by the patent ductus arteriosus, resulting in similar wall thickness of the ascending aorta (AA) and main pulmonary artery (MPA). After birth, as the ductus arteriosus closes and pulmonary arterial pressure decreases, attenuation of medial smooth muscle occurs such that the ratio of medial thickness to external diameter decreases from about 25% in fetuses to less than 10% in infants 3 to 6 months of age. After the first year of life, thickness of the MPA is normally less than half that of the adjacent ascending aorta, although the diameters of the two great arteries remain the same relative to one another [1]. During homeostatic conditions, the total pulmonary and systemic blood flows are essentially identical. In spite of their comparable blood flow rate and common embryologic origin, the anatomic characteristics of these two segments of the cardiovascular system differ substantially [2]. Futhremore, both these arteries are affected by many congenital abnormalities and also are subject to hypertension. Knowledge of the normal biomechanical properties of these great arteries is important for surgical treamtment, angioplasty, and tissue engineering. It can also provide insight into the disease processes and is a prerequisite to the study of mechanical behavior during disease conditions. In this study we characterized the biaxial mechanical behavior of both arteries as a function of location, which has not been previously performed in the pulmonary trunk.

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Effects of swimming exercise on red blood cell rheology in trained and untrained rats

Journal of Applied Physiology ◽

10.1152/jappl.2000.88.6.2074 ◽

2000 ◽

Vol 88 (6) ◽

pp. 2074-2080 ◽

Cited By ~ 26

Author(s):

Ozlem Yalcin ◽

Melek Bor-Kucukatay ◽

Umit K. Senturk ◽

Oguz K. Baskurt

Keyword(s):

Lipid Peroxidation ◽

Blood Cell ◽

Transit Time ◽

Red Blood Cell ◽

Swimming Exercise ◽

Aggregation Index ◽

Control Value ◽

Cell Rheology ◽

Transient Impairment ◽

Rbc Aggregation

Red blood cell (RBC) mechanical properties were investigated after swimming exercise in trained and untrained rats. A group of rats was trained for 6 wk (60 min swimming, daily), and another group was kept sedentary. Blood samples were obtained either within 5 min or 24 h after 60 min swimming in both groups. In the untrained rats, the RBC aggregation index decreased to 2.60 ± 0.4 immediately after exercise from a control value of 6.73 ± 0.18 ( P < 0.01), whereas it increased to 13.13 ± 0.66 after 24 h ( P < 0.01). RBC transit time through 5-μm pores increased to 3.53 ± 0.16 ms within 5 min after the exercise from a control value of 2.19 ± 0.07 ms ( P < 0.005). A very significant enhancement (166%) in RBC lipid peroxidation was detected only after 24 h. In the trained group, the alterations in all these parameters were attenuated; there was a slight, transient impairment in RBC deformability (transit time = 2.64 ± 0.13 ms), and lipid peroxidation was found to be unchanged. These findings suggest that training can significantly limit the hemorheological alterations related to a given bout of exercise. Whether this effect is secondary to the training-induced reduction in the degree of metabolic and/or hormonal perturbation remains to be determined.

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Density indicator method to measure pulmonary blood flows

Journal of Applied Physiology ◽

10.1152/jappl.1986.60.1.327 ◽

1986 ◽

Vol 60 (1) ◽

pp. 327-334 ◽

Cited By ~ 11

Author(s):

L. Gamas ◽

J. S. Lee

Keyword(s):

Optical Measurement ◽

Isotonic Saline ◽

Measuring System ◽

Base Line ◽

Indicator Method ◽

Blood Flows ◽

Rbc Aggregation ◽

Dilution Curves

The injection of plasma, saline, or erythrocyte (RBC) concentrate into the pulmonary circulation produces a change in the gravimetric density of the blood outflow similar to the dilution curve of dye. We used an improved density-measuring system to assess the flow of these density indicators through the lung in vivo and in vitro perfused dog lobe. From the in vitro density-dilution curves of plasma and RBC concentrate we calculated the pulmonary flow rate and found it to be 1.04 +/- 0.02 (SD) times the measured one. The outflow-dilution curves of gravimetric density were not as broad as those of optical density following in vivo injection of plasma bolus containing indocyanine green, and the gravimetric measurements dipped to base line, whereas the optical measurement did not. The density-dilution curves of isotonic saline injection are similar to that of plasma. Following injection of RBC concentrates with the dye, density changes in the pulmonary outflow lag behind the emergence of the dye. This was presumably related to RBC aggregation in the concentrates. In reference to the injected plasma, no loss in the density indicators for saline and RBC injection was observed. Based on these results and the similarity of the density indicators to the blood, we conclude that the plasma and isotonic saline are good density indicators to be used for the determination of pulmonary blood flows.

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Effects of trypsin on aggregation, disaggregation and aggregate morphology of red blood cells in autologous plasma and serum

10.1101/2021.06.24.449744 ◽

2021 ◽

Author(s):

Yury Aleksandrovich Sheremet'ev

Keyword(s):

Red Blood Cells ◽

Surface Charge ◽

Blood Cells ◽

Cell Aggregates ◽

Trypsin Treatment ◽

Autologous Plasma ◽

Erythrocyte Surface ◽

Rbc Aggregation ◽

Aggregate Morphology ◽

Serum Trypsin

We study the influence of trypsin on aggregation, disaggregation, and aggregate morphology of RBCs in autologous plasma and serum. The effect of trypsin on the surface charge of red blood cells and the aggregation of glutaraldehyde fixed cells after treatment with the enzyme was also studied. RBC aggregation was studied by means of an aggregometer and microscopic observations. The results obtained in this study indicate that trypsin treatment increases RBCs aggregation in autologous plasma and serum. The disaggregation of erythrocytes after trypsin treatment considerably decreased in autologous plasma and serum. Increase in the strength of red blood cell aggregates was observed in autologous plasma and serum. The microscopic images of RBCs aggregates indicate the formation of globular (pathologic) structures of aggregates in autologous plasma and serum. Trypsin decrease the surface charge of RBCs. In autologous plasma and serum, the cup shapes of RBCs appear. The control RBCs fixed with glutaraldehyde were not aggregated after their placement in autologous plasma. At the same time, red blood cells pretreated with trypsin and fixed with glutaraldehyde interact with each other in autologous plasma. The physiological significance of glycoproteins of erythrocyte surface for RBCs aggregation was discussed.

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