Plasma Separation Research Articles

Pregnancy-induced severe hypertriglyceridemia effectively treated with therapeutic plasmapheresis

IntroductionHypertriglyceridemia is associated with significant morbidity during pregnancy. Hypertriglyceridemia-induced pancreatitis (HTGP) is associated with genetically determined dyslipidemia or a secondary condition such as diabetes, alcohol, pregnancy, or medication use. The lack of data on the safety of drugs to be used to decrease triglyceride levels during pregnancy dictates that other strategies must be chosen. Patient and methodsWe describe a case of a pregnant woman with severe hypertriglyceridemia treated with two different techniques of plasmapheresis (Dual Filtration apheresis and Centrifugal Plasma Separation). ResultsThe patient could be treated throughout the pregnancy, with good control of the triglycerides, and a healthy baby was born. ConclusionHypertriglyceridemia is a major issue during pregnancy. The use of plasmapheresis is a safe and efficient tool in that clinical scenario.

Extracorporeal therapy of sepsis by purified granulocyte concentrates: ex vivo circulation model.

Immune cell dysfunction is a central part of immune paralysis in sepsis. Granulocyte concentrate (GC) transfusions can induce tissue damage via local effects of neutrophils. The hypothesis of an extracorporeal plasma treatment with granulocytes is to show beneficial effects with fewer side effects. Clinical trials with standard GC have supported this approach. This ex vivo study investigated the functional properties of purified granulocyte preparations during the extracorporeal plasma treatment. Purified GC were stored for up to 3 days and compared with standard GC in an immune cell perfusion therapy model. The therapy consists of a plasma separation device and an extracorporeal circuit. Plasma is perfused through the tubing system with donor immune cells of the GC, and only the treated plasma is filtered for re-transfusion. The donor immune cells are retained in the extracorporeal system and discarded after treatment. Efficacy of granulocytes regarding phagocytosis,oxidativeburst as well as cell viability and metabolic parameters were assessed. In pGC, the metabolic surrogate parameters of cell functionality showed comparable courses even after a storage period of 72h. In particular, glucose and oxygen consumption were lower after extended storage. The course oflactate dehydrogenase concentration yields no indication of cell impairment in the extracorporeal circulation. The cells were viable throughout the entire study period and exhibited preserved phagocytosis and oxidativeburst functionality. The granulocytes demonstrated full functionality in the 6 h extracorporeal circuits after 3 days storage and in septic shock plasma. This is demonstrating the functionality of the system and encourages further clinical studies.

Hemolysis prediction in bio-microfluidic applications using resolved CFD-DEM simulations

Background and ObjectiveHemolysis, namely hemoglobin leakage from red blood cells (RBCs), is one of the major sources of incorrect results in clinical tests, especially when passive microfluidics is involved. This is due to small characteristic dimensions which could cause strong RBCs deformation. Prediction of hemolysis is essential in the design and optimization of lab-on-a-chip devices for cell sorting and plasma separation. The aim of this work is to provide a numerical simulation tool this purpose applicable to real-scale bio-microfluidic devices with affordable computational cost. MethodsBlood is modelled as a suspension of biological cells, mainly RBCs, in liquid plasma assumed as a Newtonian, incompressible carrier fluid. Therefore, the physics of cells and carrier fluid is coupled by means of an immersed boundary concept known as resolved CFD-DEM. In this approach, the Navier-Stokes equations are numerically solved through a finite volume method with an additional penalty term to account for the presence of RBCs. RBCs’ positions and velocities are updated by solving Newton and Euler equations for conservation of linear and angular momentum. To model the RBCs deformation, a reduced-order model is employed, where each RBC is represented by a clump of overlapping rigid spheres connected by fictional numerical bonds, whose properties are tuned to reproduce the ones of RBCs viscoelastic membrane. This coupled approach allows access to cell-level information and facilitates the usage of strain-based hemolysis models. ResultsDifferent micro-channel geometries and blood hematocrits are simulated, to explore the influence of these factors on RBCs damage. Statistical analysis is performed to extract relevant biophysical quantities from numerical simulations such as hemolysis index distribution at the channel exit. Finally, the effect of carrier fluid viscosity is studied in relation to cell-cell interactions. ConclusionsSimulation results show that hemolysis occurrence is almost independent of the hematocrit values in the microchannel, implying the possibility to speed up calculation using low hematocrit values. Nevertheless, using whole blood viscosity for the carrier fluid overestimates the value of the hemolysis index by almost one order of magnitude.

Integrating Bio-Sensing Array with Blood Plasma Separation on a Centrifugal Platform.

Numerous immunoassays have been successfully integrated on disc-based centrifugal platforms (CDs) over the last 20 years. These CD devices can be used as portable point-of-care (POC) platforms with sample-to-answer capabilities where bodily fluids such as whole blood can be used as samples directly without pre-processing. In order to use whole blood as a sample on CDs, centrifugation is used to separate red blood cells from plasma on CDs. There are several techniques for using specific fluidic patterns in the centrifugal fluidic network, such as reciprocation, that enhances the sensitivity of the immunoassays, including those using microarray antigen membranes. Present work demonstrates, for the first time, simultaneous integration of blood plasma separation (BPS) and reciprocation on the CD platform. The integrated design allows plasma that is separated from the red blood cells in a sedimentation chamber to flow into the reciprocation chamber via a narrow connecting channel of 0.5 mm × 0.5 mm cross-section. Due to the small cross-section of the connecting channel, there is no inflow of the red blood cell into the reciprocation chamber during subsequent fluidic operations of the CD. While no inflow of the red blood cells into the reciprocation chamber was observed, the conditions of 20 g jerk acceleration were also simulated in ANSYS finite element analysis software, and it was found that the CD design that was used is capable of retaining red blood cells in the sedimentation chamber. Experimentally, the isolation of red blood cells in the sedimentation chamber was confirmed using the ImageJ image processor to detect the visible color-based separation of the plasma from the blood. A fluorescent analyte testing on the bio-sensing array of the presented novel integrated design and on the standard reciprocation design CD was conducted for 7 min of reciprocation in each case. The test analyte was Europium Streptavidin Polystyrene analyte (10-3 mg/mL) and the microarray consisted of Biotin bovine serum albumin (BSA) dots. The fluorescent signals for the standard and integrated designs were nearly identical (within the margin of error) for the first several minutes of reciprocation, but the fluorescent signal for the integrated design was significantly higher when the reciprocation time was increased to 7 min.

Clinical use of plasmafiltration coupled with adsorption

Coupled plasma filtration adsorption is an extracorporeal therapy that combines plasma separation and adsorption of inflammatory mediators and toxins, followed by hemofiltration to control volume overload and removal of small and medium-sized water-soluble mediators. Although it is not new, there are still doubts about its clinical role. Evidence indicates that the coupled plasma filtration adsorption is highly efficient in removing inflammatory molecules in sepsis. So far it has not been shown to reduce mortality, but it is possible to achieve a better hemodynamic benefit over convective therapies. On the other hand, the absorptive component makes it possible to purify larger mediators associated with causes of non-septic acute kidney injury, such as myoglobin, toxins associated with liver failure and others, allowing that coupled plasma filtration adsorption indications to be expanded to various clinical settings with a high inflammatory component, particularly when it is required to manage several organ dysfunctions simultaneously.

Retrospective analysis of intra-patient laboratory variation demonstrates that the BD Vacutainer® Barricor™ blood collection tube reduces troponin variation

ObjectiveThe BD Vacutainer® Barricor™ plasma blood collection tube uses a mechanical separator during centrifugation to separate plasma from the cellular elements of blood. Compared to use of plasma separator tubes (PST™) with gel, Barricor™ produces a cleaner sample with less residual cellular content. We sought to determine if Barricor™ reduces pre-analytical error compared to PST™. Design & MethodsWe used a model previously published that utilizes serial differences between intra-patient measurements transformed into a Taylor series of variation vs time with the y-intercept equal to the sum of short-term analytic variation, preanalytic variation and biologic variation. The intra-patient variation of chloride, sodium, potassium, and troponin-T (hs-TnT) obtained from the Emergency Department of a large tertiary care center sampled with PST™ (May 2015-April 2018, n = 59,762 specimens) or Barricor™ (May 2018-May 2021, n = 61,512 specimens) was evaluated. All specimens were analyzed on either Roche Modular or Cobas® instruments. For each analyte, pairs of intra-patient results were tabulated and separated by 1 h intervals. The average between-pair variations were then regressed against time. We also determined the number of intra-patient outliers using the reference change value for each analyte. ResultsThe Barricor™ hs-TnT y-intercept (-0.0132) was significantly lower than the PST™ intercept (0.9109; p = 0.022). This was also true for chloride (y-intercept = 1.0067 in Barricor™ and 1.3431 in PST™, p = 0.037). The percentage of hs-TnT outliers was significantly lower in Barricor™ (8.32 %) vs PST™ (12.2 %; p < 0.001). ConclusionThe analytical and biological variations are assumed to be steady over the study periods; we ascribe the difference in the y-intercept to the preanalytical effect of the Barricor™ tube reducing platelets and other cellular debris.

Heparin/polyethyleneimine dual-sided functional polyvinylidene fluoride plasma separation membrane for bilirubin removal

Herein, a novel heparin/polyethyleneimine (PEI) dual-sided functional polyvinylidene fluoride (PVDF) plasma separation membrane structure is proposed. Bilirubin is removed using this membrane via one-step “anticoagulation-adsorption”. When blood flows in the membrane, the inner side of the membrane can prolong clotting time. Meanwhile, bilirubin contained in plasma is filtrated through the membrane. Bilirubin is adsorbed on the outer side of the membrane to be removed. Herein, branched PEI was grafted on the outer side of the PVDF plasma separation membrane to construct the bilirubin adsorption functional layer. Then, heparin was grafted on the inner side to construct a self-anticoagulant functional layer. The dual-sided functional PVDF plasma separation membrane was prepared. The results showed that PEI and heparin could be grafted on the outer side and the inner side of the PVDF plasma separation membrane, separately. Bilirubin's competitive adsorption property of the outer side of the membrane was enhanced. Hemocompatibility of the inner side of the membrane was strengthened. The plasma permeability of the novel membrane gradually decreased to 250 L·m−2·h−1bar−1. The total plasma protein sieving coefficient of the novel membrane was larger than 80 %. Total bilirubin and direct bilirubin adsorption capacity reached 22.5 mg/g and 20.5 mg/g via one-step “anticoagulation-adsorption”. The novel membrane prepared in this work can effectively simplify traditional hemoperfusion therapy, implying its great potential application.

Thrombotische Mikroangiopathien

In the emergency room, patients with anemia and thrombocytopenia are common. Although these findings can often be explained by the medical situation, thrombotic microangiopathy is an important differential diagnosis. In this case, occlusion of the smallest vessels consequently leads to functional impairment of the affected organs. Patients generally present with symptoms of organ dysfunction, e.g., in the kidney or brain. Characteristically, Coombs-negative fragmentation of erythrocytes with hemolysis occurs in the area of the occluded vessels. Lactate dehydrogenase levels are elevated, and platelets and haptoglobin are reduced. Differential diagnoses beyond thrombotic microangiopathy that should be considered are numerous and diverse in their pathophysiology. Rapid workup is needed, because sometimes aspecific treatment must be initiated rapidly. For example, thrombotic thrombocytopenic purpura leads to death in about 90% of patients if left untreated. However, by reconstitution of the underlying deficiency of the so-called ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) by plasma separation, survival can be ensured in most cases. Complement-mediated hemolytic uremic syndrome should also be considered and, if suspected, treated with complement inhibition. In many cases, however, thrombotic microangiopathy reflects adisorder elsewhere and may be amanifestation of severe hypertension or acoagulation disorder, such as disseminated intravascular coagulation or antiphospholipid syndrome. It can also be observed as aconsequence of drug therapies or metabolic derangement. Systemic workup is therefore necessary for rapid clarification of differential diagnoses.

Real-time monitoring and actuation of a hybrid siphon valve for hematocrit-independent plasma separation from whole blood.

Centrifugal microfluidics have emerged as a pivotal area of research spanning multiple domains, including medicine and chemistry. Among passive valving strategies, siphon valves have gained prominence due to their inherent simplicity and self-reliance, eliminating the need for external equipment. However, achieving optimal valve performance mandates supplementary elements like surface adjustments or pneumatic pressure. These introduce intricacies such as time-dependent behavior and augmented spatial demands. This research introduces inventive design and manufacturing methodologies to amplify siphon valve functionality. Our proposed innovation situates the siphon microchannel on the external surface of the primary chamber, linked via an inlet. The crux of novelty lies in the adaptable material selection for the microchannel's upper or lower surfaces, allowing the integration of hydrophilic materials such as glass or super hydrophilic coverslips, ensuring a leakage-free operation. Our approach offers a streamlined concept and manufacturing process, ensures consistent time-independent functionality, and accommodates the integration of multiple siphon valves within a solitary chamber, tailored for specific applications. Experimental evaluations validate a robust alignment between acquired data and analytical outcomes based on a modified equation. A customized disc is engineered, featuring four siphon valves meticulously calibrated for hematocrit (HCT) levels spanning from 20% to 50% at 10% intervals. Harnessing these valves yields a substantial surge in plasma separation efficiency, scaling up to 75%. Notably, this performance eclipses traditional single-valve reliant microfluidic methodologies, achieving a purity level exceeding 99% in plasma separation. These findings underscore the auspicious practical applicability of our proposed technique in plasma separation, fostering heightened platelet concentration, and expediting blood sample analysis.

Activity of Labile Coagulation Factors, Section Factor X and Fibrinogen Level in Frozen Plasma versus Fresh Frozen Plasma

Introduction: Fresh Frozen Plasma (FFP) is a blood component separated from whole blood and frozen below -30°C within 8 hours of donation for optimum preservation of coagulation factors. However, logistic and geographical reasons may hamper separation of plasma within 8 hours and the separation may have to be delayed to between 8 and 24 hours and then frozen below -30°C which is called as Frozen Plasma (FP). Plasma separated between 8 and 24 hours is a licensed blood component in the United States of America (USA) for therapeutic use similar to FFP. It is not licensed in India leading to frequent shortage of plasma. Aim: To compare the activity of factors V, VIII and X and the level of fibrinogen between FFP and FP, so as to assess the therapeutic use of FP for formulating recommendation as licensed blood component. Materials and Methods: A prospective observational study was conducted in the Department of Transfusion Medicine at Seth GS Medical College and KEM Hospital, Mumbai, Maharashtra, India. The duration of the study was 10 months, from January 2018 to October 2018. 50 units each of FFP and FP matched for the camp location, age, gender and blood group were selected. There were 44 males and six females in each of FFP and FP groups. They were compared for the activity of labile coagulation factors (factors V and VIII) and stable factor X. The level of fibrinogen was also measured in both components. It was done within 30 days of preparation of plasma. The mean values of each of the four parameters for FFP and FP were calculated and compared for statistical significance (p) by using unpaired Student’s t-test. Microsoft Excel 2016 was used for statistical analysis. The p-value &lt;0.05 was considered statistically significant. Results: The mean age of FFP and FP individuals (blood donors) was 31.2 and 31.3 years respectively, while the median age in years was 31 and 30.5, respectively. The activity/level of all the tested coagulation factors was lower in FP as compared to FFP. The difference was statistically significant for factor VIII (p-value &lt;0.05). It was not significant for factor V, X and fibrinogen. The level/activity of coagulation factors in FP, though lower than that in FFP, fell within normal reference range in 90-95% of units. Conclusion: FP may be used as a therapeutic alternative to FFP excluding patients of haemophilia A in whom factor VIII concentrate and cryoprecipitate are considered better therapeutic modalities. Results of similar multicentre studies will help in formulating recommendations regarding licensing.

A microfluidic plasma separation device combined with a surface plasmon resonance biosensor for biomarker detection in whole blood.

Biomarker detection in whole blood enables understanding of the cause, progression, relapse or outcome of treatment of a disease. Conventional biomarker detection techniques, such as enzyme-linked immunosorbent assay, polymerase chain reaction, and immunofluorescence, require long assay time, costly laboratory instruments, large reagent volume and sample pre-processing. Hence, there is an unmet need for reliable capture and detection of biomarkers in unprocessed blood which are adaptable to point-of-care (POC) testing. Here, we present a simple, low-cost, and rapid protein detection device from whole blood samples which has the potential to be employed in a POC setting. The platform consists of two components: a plasma separation device that extracts plasma from whole blood without the application of any external active forces and a SPR sensor chip that uses a label-free optical technique for the detection of biomarkers in the extracted plasma. We have demonstrated the detection of IgG and IgM biomolecules in unprocessed blood at concentrations lower than the physiological value within 15 min. The proposed technique has the potential for improving the diagnosis and screening of many diseases, including cancer, influenza, human immunodeficiency virus, and SARS-Cov2 at POC.

Collection of Plasma Samples in Areas with Limited Healthcare Access.

Regular monitoring of various biomarkers and molecular panels in plasma can significantly help to prevent disease onset and improve its management and final outcomes. Many groups can benefit from monitoring programs focusing on the prevention of cardiovascular diseases, evaluation of environmental exposure impacts, or the prevention/management of cancer. Improvement in therapeutic options in part due to targeted therapeutic agents and monoclonal antibody therapies has led to a significant sized population that can be described as "cancer survivors." These patients, although in remission from their original disease, are at significant risk for the recurring disease and must be monitored for adverse events. Monitoring is, however, not an easy task; requiring a high level of complexity in lab facilities and blood/plasma sampling, collection, and storage must occur under tightly controlled conditions. These demanding circumstances are especially difficult to attain in rural areas and in historically marginalized populations. The Telimmune Plasma Separation Card (TPS card or TPSC) has been developed to enable diagnostic plasma sampling, collection, and stabilization in locations that may be remote to laboratory or clinic. The TPSC requires a drop of blood applied to a top of a separation system consisting of a separation membrane and collection disk. In 3min, the TPSC device separates plasma from erythrocytes and deposits a defined volume of plasma into a collection disc which is air-dried for 15min to deliver a stabilized, volumetric plasma sample, which may be stored or shipped at ambient temperatures with minimal biological risk. Extraction of proteins and metabolites is then achieved in well-equipped laboratories using protocols discussed in this chapter.

Analysis of Risk Factors and Protective Strategies for Tube Blockage in Patients with Drug-Induced Liver Failure Based on Artificial Liver Therapy.

To analyse the influencing factors of tube blockage during the treatment of artificial liver in patients with drug-induced liver failure and explore effective patient protection strategies. In this study, 49 patients with pharmacological (antituberculosis drugs, antibiotics, proprietary Chinese medicine, gastric drugs, and antihyperthyroid drugs) liver failure admitted to our hospital from June 2015 to December 2021 were selected for prospective analysis. Clinical indicators and general data of all patients were collected and collated, risk factors leading to the obstruction of artificial liver treatment were analysed, and corresponding protective measures were proposed. The incidence of tube blockage was 5.32% (10 times) in 49 patients with pharmacological liver failure treated 188 times with artificial liver therapy. The incidence of tube blockage was significantly higher in patients in the PDF mode than in those in the PP and PE modes (P < 0.05), and there were differences in the location of blocked tubes between the treatment modes. Blocked tubes occurred more often in the venous cauldron of the circuit in the PDF mode and in the plasma separator of the circuit in the PP mode. The incidence of tube blockage was significantly lower in patients with no more than 3 treatments than in those with 3 to 5 treatments and those with more than 5 treatments (p < 0.05). The incidence of catheter blockage was higher in patients with PTA values ≤20% than in those with PTA values between 20% and 30%, and higher than in those with PTA values above 30% (P < 0.05). The risk factors of tube plugging in patients with liver failure treated with artificial liver include different treatment modes, different treatment times, and different PTA values. The PDF mode has a higher rate of tube plugging than PE or PP treatment modes. The more the number of treatment times and the lower the PTA value of patients, the more tube plugging is likely to occur.

Sensitive and Quantitative Point-of-Care HIV Viral Load Quantification from Blood Using a Power-Free Plasma Separation and Portable Magnetofluidic Polymerase Chain Reaction Instrument.

Point-of-care (POC) HIV viral load (VL) tests are needed to enhance access to HIV VL testing in low- and middle-income countries (LMICs) and to enable HIV VL self-testing at home, which in turn have the potential to enhance the global management of the disease. While methods based on real-time reverse transcription-polymerase chain reaction (RT-PCR) are highly sensitive and quantitatively accurate, they often require bulky and expensive instruments, making applications at the POC challenging. On the other hand, although methods based on isothermal amplification techniques could be performed using low-cost instruments, they have shown limited quantitative accuracies, i.e., being only semiquantitative. Herein, we present a sensitive and quantitative POC HIV VL quantification method from blood that can be performed using a small power-free three-dimensional-printed plasma separation device and a portable, low-cost magnetofluidic real-time RT-PCR instrument. The plasma separation device, which is composed of a plasma separation membrane and an absorbent material, demonstrated 96% plasma separation efficiency per 100 μL of whole blood. The plasma solution was then processed in a magnetofluidic cartridge for automated HIV RNA extraction and quantification using the portable instrument, which completed 50 cycles of PCR in 15 min. Using the method, we achieved a limit of detection of 500 HIV RNA copies/mL, which is below the World Health Organization's virological failure threshold, and a good quantitative accuracy. The method has the potential for sensitive and quantitative HIV VL testing at the POC and at home self-testing.

The relationship of D-Dimer level with various diseases

D-dimer is a biomarker of thrombosis considered to predict poor outcomes in patients with various diseases. This study aimed to find out the relationship between levels of D dimer in different diseases. 556 blood sample analyses for D dimer Patients' were collected from private laboratories, isolation, and health care centres in the Derna, Al- Gubba City, and its surrounding areas, Plasma separation from the tube containing sodium citrate, Preparation of I-Chroma D-Dimer Quantitative kits reagent. The Frequency and Percent of the Gender were 278 (50%) for males, 278 (50%) for females and for Chronic Diseases, the highest percent for Pneumonia was 121 (21.8%), followed by Blood Pressure at 77 (13.8 %). Diabetes Miletus 51 (9.2%), and for other diseases 71 (12.8%), the type of infection, the highest percent for Viral Infection was 498 (89.6%), followed by Surgery 23 (4.1%), Deep Vein Thrombosis 18 (3.2%), and for Respiratory Diseases 17 (3.1%), the level of D dimer which the highest percent for Moderate 247 (44.4%), followed by High 149 (26.8%). The result of D dimer was Normal 109 (19.6%), and the very high result of 51 (9.2%), the relationship between D dimer result and chronic disease was the highest for blood pressure followed by pneumonia, diabetes Miletus, Anemia, kidney disease, and Heart disease, The correlation between D dimer for age and chronic diseases, p-value &lt; &amp; = 0.05, and there is not a significant relationship between D dimer and type of infection and gender p-value &lt; 0.05. We concluded that the obtained results prove that among obtained results, there is a strong relationship between age and chronic diseases, an increase in the level of D-dimer, level in the blood is not an indication of a specific disease, but rather a signal and alert for several diseases, many diseases

A Compact Control System to Enable Automated Operation of Microfluidic Bioanalytical Assays.

We describe a control system for operating valve-enabled microfluidic devices and leverage this control system to carry out a complex workflow of plasma separation from 8 μL of whole blood followed by on-chip mixing of plasma with assay reagents for biomarker detection. The control system incorporates pumps, digital pressure sensors, a microcontroller, solenoid valves and off-the-shelf components to deliver high and low air pressure in the desired temporal sequence to meter fluid flow and actuate microvalves. Importantly, our control system is portable, which is suitable for operating the microvalve-enabled microfluidic devices in the point-of-care setting.

A capillary flow-driven microfluidic device for point-of-care blood plasma separation

Plasma has significant utility as an input for diagnostics and screening for conditions such as viral infections, cancer, and more. However, plasma is difficult to obtain at the point-of-care, as separation from whole blood is typically carried out via centrifugation. We have designed and optimized a low-cost, simple-to-operate microfluidic device which carries out the separation of plasma from whole blood. The device utilizes depth filtration as its separation mechanism and collects plasma via capillary action, allowing for operation without components that drive flow externally. We first optimized device dimensions and operating parameters and demonstrated consistent separation efficiencies for the samples with hematocrits ranging from 25–65%. The impact of input sample hematocrit percentage on flow rate through the device was also examined, with samples with hematocrits greater than 45% decreasing plasma flow rate. Lastly, we evaluated the ability of this device to produce plasma with a high protein concentration and found no significant difference between protein levels in samples from the device compared to samples produced via centrifugation. This system produced plasma with a maximum separation efficiency of 88.5% and achieved a maximum plasma volume of ∼14 μl from a 50 μl whole blood input. The low cost, simplicity of operation, and high plasma quality associated with this device give it many advantages in a point-of-care setting. This device could be integrated into plasma-based diagnostic workflows to increase access to various types of disease testing and monitoring.

Alphalisa immunoassay enabled centrifugal microfluidic system for “one-step” detection of pepsinogen in whole blood

In recent years, gastric cancer has received extensive attention and prevention. To achieve rapid and highly sensitive detection of gastric function index without blood pretreatment, in this study, for the first time, we investigated an intelligent system combining centrifugal microfluidic and Alphalisa immunoassay for early detection of pepsinogen. Based on the “interconnected-collecting chambers collinear with rotational center" (ICCRC) structure, the system could automatically separate whole blood and perform immune detection using Alphalisa to achieve quantitative detection of pepsinogen Ⅰ (PG Ⅰ) and PG Ⅱ. The whole detection process took place in “one-step” in less than 12 min. The plasma separation efficiency reached 99 %, and limit of detection values of 0.75 ng/mL for PG I and 0.85 ng/mL for PG II were obtained. The results indicated that the portable system could detect pepsinogen with high sensitivity and accuracy, providing a great potential for highly integrated on-chip point-of-care testing in future.

Extremely Precise Blood-Plasma Separation from Whole Blood on a Centrifugal Microfluidic Disk (Lab-on-a-Disk) Using Separator Gel.

Due to the expansion of point-of-care devices, proposing a convenient and efficient method for blood-plasma separation would help with the use of point-of-care devices. Commercial microfluidic chips are only able to separate a limited amount of plasma, and the majority of these chips need an active valve system, which leads to increase manufacturing cost and complexity. In this research study, we designed a centrifugal microfluidic disk with a passive valve for ultra-accurate and efficient blood-plasma separation on a large scale (2-3 mL). The disk contained a separator gel, which, after applying the centrifugal force, separated the plasma and red blood cells. The passive valve worked based on the inertial force and was able to transfer more than 90% of the separated plasma to the next chamber. The results demonstrated that the separated plasma was 99.992% pure. This study compared the efficiency of the disk containing separating gel with the common lab-on-a-disk design for plasma separation. A comparison of the results showed that although the common lab-on-a-disk design could separate almost pure plasma as the disk contained separator gel, it could only transfer 60% of plasma to the next chamber.

A microfluidic device to separate high-quality plasma from undiluted whole blood sample using an enhanced gravitational sedimentation mechanism

The growing interest in lab-on-a-chip systems for plasma separation has led to the presentation of various devices. Trench-based devices benefiting from gravitational sedimentation are efficient structures with air-locking and low speed-drawbacks. The present study introduces a fast, hemolysis-free, highly efficient blood plasma separation microfluidic device. The proposed device is based on gravitational sedimentation combined with dielectrophoresis force to promote the purity of the separated plasma, reduce the separation process time, and overcome the air-locking problem. The effect of geometrical parameters on the separation process is investigated using finite element analysis to attain optimal design specifications. A drop of whole blood (10 μl) is injected into the fabricated chip at four flow rates of 70 nl/s to 100 nl/s. It takes less than 4 min to obtain 2.2 μl plasma from undiluted blood without losing plasma proteins. Additionally, a porous Melt-Blown Polypropylene (MBPP) layer is used to eliminate the air-locking problem, which in previous trench-based microsystems led to time-consuming device preparation steps. Blood samples with various hematocrits (15%–65%) are tested with the applied voltages of 0–20 Vpp through the optimized structure. A purity of 99.98% ± 0.02% (evaluated by hemocytometry) is achieved using optimized dielectrophoresis force by the applied voltage of 20 Vpp, which is more than the previous studies. The UV–Visible spectroscopy results confirm obtaining a non-hemolyzed sample at a flow rate of 70 nl/s. The proposed device achieves a relative increase in the flow rate compared to similar previous studies while maintaining the high quality of the separated plasma. This achievement lies in using the MBPP layer and combining two separation methods.