Blood Plasma Separation Device Research Articles

Polydimethylsiloxane Surface Modification of Microfluidic Devices for Blood Plasma Separation.

Over the last decade, researchers have developed a variety of new analytical and clinical diagnostic devices. These devices are predominantly based on microfluidic technologies, where biological samples can be processed and manipulated for the collection and detection of important biomolecules. Polydimethylsiloxane (PDMS) is the most commonly used material in the fabrication of these microfluidic devices. However, it has a hydrophobic nature (contact angle with water of 110°), leading to poor wetting behavior and issues related to the mixing of fluids, difficulties in obtaining uniform coatings, and reduced efficiency in processes such as plasma separation and molecule detection (protein adsorption). This work aimed to consider the fabrication aspects of PDMS microfluidic devices for biological applications, such as surface modification methods. Therefore, we studied and characterized two methods for obtaining hydrophilic PDMS surfaces: surface modification by bulk mixture and the surface immersion method. To modify the PDMS surface properties, three different surfactants were used in both methods (Pluronic® F127, polyethylene glycol (PEG), and polyethylene oxide (PEO)) at different percentages. Water contact angle (WCA) measurements were performed to evaluate the surface wettability. Additionally, capillary flow studies were performed with microchannel molds, which were produced using stereolithography combined with PDMS double casting and replica molding procedures. A PDMS microfluidic device for blood plasma separation was also fabricated by soft lithography with PDMS modified by PEO surfactant at 2.5% (v/v), which proved to be the best method for making the PDMS hydrophilic, as the WCA was lower than 50° for several days without compromising the PDMS's optical properties. Thus, this study indicates that PDMS surface modification shows great potential for enhancing blood plasma separation efficiency in microfluidic devices, as it facilitates fluid flow, reduces cell aggregations and the trapping of air bubbles, and achieves higher levels of sample purity.

Development of a biodegradable microfluidic paper-based device for blood-plasma separation integrated with non-enzymatic electrochemical detection of ascorbic acid

In the present article, we developed an electrochemical microfluidic paper-based device (EμPAD) for the non-enzymatic detection of Ascorbic Acid (AA) concentration in plasma using whole human blood. We combined LF1 blood plasma separation membrane and Whatman grade 1 filter paper to separate plasma from whole blood through wax printing. A screen-printed electrode (SPE) was modified with spherical-shaped MgFe2O4 nanomaterial (n-MgF) to improve the catalytic properties of SPE. The n-MgF was prepared via hydrothermal method, and its material phase and morphology were confirmed via XRD, FTIR, TEM, SEM, and AFM analysis. The fabricated n-MgF/SPE/EμPAD exhibited detection of AA ranging from 0 to 80 μM. The obtained value of the detection limit, limit of quantification, sensitivity, and response time are 2.44 μM, 8.135 μM, 5.71 × 10−3 mA μM−1 cm−2, and 10 s, respectively. Our developed n-MgF/SPE/EμPAD shows marginal interference with the common analytes present in plasma, such as uric acid, glutamic acid, glucose, urea, lactic acid, and their mixtures. Overall, our low-cost, portable device with its user-friendly design and efficient plasma separation capability offers a practical and effective solution for estimating AA concentration from whole human blood in a single step.

A self-pressure-driven blood plasma-separation device for point-of-care diagnostics

We aimed to develop a portable, simple-to-use, and self-pressure-driven blood plasma-separation device that can be combined with rapid diagnostic test kits. This simple, disposable, and electrical equipment-free apparatus has been designed to separate plasma from a few microliters of blood with only hand-powered operation. The refined plasma sample is then delivered to multiple lateral flow assay kits directly connected to the device for the detection of various serological markers. The required time for all steps was just 1 min. We validated the device through multifaceted experiments. The developed multifunctional device enables to perform all blood test steps of diagnostic medical examination at the point-of-care.

Microfluidic Paper-Based Blood Plasma Separation Device as a Potential Tool for Timely Detection of Protein Biomarkers.

A current challenge regarding microfluidic paper-based analytical devices (µPAD) for blood plasma separation (BPS) and electrochemical immunodetection of protein biomarkers is how to achieve a µPAD that yields enough plasma to retain the biomarker for affinity biosensing in a functionalized electrode system. This paper describes the development of a BPS µPAD to detect and quantify the S100B biomarker from peripheral whole blood. The device uses NaCl functionalized VF2 filter paper as a sample collection pad, an MF1 filter paper for plasma retention, and an optimized microfluidic channel geometry. An inverted light microscope, scanning electron microscope (SEM), and image processing software were used for visualizing BPS efficiency. A design of experiments (DOE) assessed the device’s efficacy using an S100B ELISA Kit to measure clinically relevant S100B concentrations in plasma. The BPS device obtained 50 μL of plasma from 300 μL of whole blood after 3.5 min. The statistical correlation of S100B concentrations obtained using plasma from standard centrifugation and the BPS device was 0.98. The BPS device provides a simple manufacturing protocol, short fabrication time, and is capable of S100B detection using ELISA, making one step towards the integration of technologies aimed at low-cost POC testing of clinically relevant biomarkers.

Sub-Minute Analysis of Lactate from a Single Blood Drop Using Capillary Electrophoresis with Contactless Conductivity Detection in Monitoring of Athlete Performance.

A simple and fast method for the analysis of lactate from a single drop of blood was developed. The finger-prick whole blood sample (10 µL) was diluted (1:20) with a 7% (w/v) solution of [tris(hydroxymethyl)methylamino] propanesulfonic acid and applied to a blood plasma separation device. The device accommodates a membrane sandwich composed of an asymmetric polysulfone membrane and a supporting textile membrane that allows the collection of blood plasma into a narrow glass capillary in less than 20 s. Separated and simultaneously diluted blood plasma was directly injected into a capillary electrophoresis instrument with a contactless conductivity detector (CE-C4D) and analyzed in less than one minute. A separation electrolyte consisted of 10 mmol/L l-histidine, 15 mmol/L dl-glutamic acid, and 30 µmol/L cetyltrimethylammonium bromide. The whole procedure starting from the finger-prick sampling until the CE-C4D analysis was finished, took less than 5 min and was suitable for monitoring lactate increase in blood plasma during incremental cycling exercise. The observed lactate increase during the experiments measured by the developed CE-C4D method correlated well with the results from a hand-held lactate analyzer (R = 0.9882). The advantage of the developed CE method is the speed, significant savings per analysis, and the possibility to analyze other compounds from blood plasma.

A microfluidic device for blood plasma separation and fluorescence detection of biomarkers using acoustic microstreaming

Human blood plasma contains numerous soluble, diffusible, and secreted biomarkers that are used for clinical diagnosis and prognosis of various diseases. However, the blood of some patients is hemolyzed rapidly due to the rupture of cell membranes and releases chemicals and biological molecules that yield false-positive fluorescence detection results due to autofluorescence. The standard method for plasma separation is centrifugation, which is difficult to be integrated with various methods for downstream biomarker detection. Herein, we report development of a novel microfluidic device that is integrated with multiple functionalities on a single disposable chip. Using the principle of bubble-induced acoustic microstreaming, we have tested whole blood controls spiked with fluorescently tagged antibodies to HIV-1 p24 protein and obtained ∼ 31.8 % plasma yield with 99.9 % plasma purity within five minutes. The separated plasma was then routed to an integrated micro-mixing chamber and mixed with HIV-1 p24 antigen conjugated beads (10 μm diameter). The bound p24 antigen-antibody complexes were captured by acoustic microstreaming and detected using a fluorescence microscope. These experiments demonstrated a detection limit of ∼17 pg/μL of p24 antibody in the plasma. The microfluidic device successfully separated plasma from the whole blood control using acoustic microstreaming and integrated with acoustic micro-pumping and micro-mixing for enrichment of biomarkers by mixing p24-bound beads with fluorescently tagged antibodies. The beads with antigen-antibody complexes were efficiently captured in a separate compartment for fluorescence microscopy and detection of biomarkers. Integration of multiple functionalities on a single disposable microfluidic chip can now facilitate rapid detection of biomarkers and be used for monitoring patients’ specimen in real time.

Ultrahigh throughput beehive-like device for blood plasma separation.

We report here a low-cost, rapid-prototyping, and beehive-like multilayer polymer microfluidic device for ultrahigh-throughput blood plasma separation. To understand the device physics and optimize the device structure, the effect of cross-sectional dimension and operational parameter on particle focusing behavior was explored using a single spiral microchannel device. Then, the blood plasma separation performance of the determined channel structure was validated using the blood samples with different hematocrits (HCTs). It was found that a high separation efficiency of 99% could be achieved using the blood sample with an HCT of 0.5% at a high throughput of 1mL/min. Finally, a multilayer microfluidic device with a novel beehive-like multiplexing channel arrangement was developed for ultrahigh-throughput blood plasma separation. The prototype device could be fabricated within ∼1 hour utilizing the laser cutting and thermal lamination methods. The total processing throughput could reach up to 72mL/min for 0.5% HCT sample with a plasma separation ratio close to 90%. Our device may hold potentials for the ultrahigh-throughput separation of blood plasma from large volume blood samples for downstream disease diagnosis.

Improved Understanding of Acoustophoresis and Development of an Acoustofluidic Device for Blood Plasma Separation

Separating blood plasma in microchannels is of great relevance to microfluidics-based biodetection. However, the physics behind the separation of plasma from whole blood using acoustophoresis (movement driven by sound waves) is not well understood. This study uses experiments and simulations to provide an improved understanding of plasma separation from whole blood using acoustophoresis. It is seen that acoustophoretic focusing of cells depend on two time scales: that of shear-induced diffusion, and that of actual acoustophoresis. These results will help in designing highly efficient blood-plasma separation devices for lab-on-a-chip applications.

Fast blood plasma separation device for point-of-care applications

In this work, a simple device for extremely fast separation of blood plasma from diluted whole blood was developed. The device accommodates an asymmetric polysulfone membrane/supporting membrane sandwich that allows collection of 10 µL blood plasma into a narrow glass capillary in less than 10 s. The composition of diluent solution was optimized in order to achieve maximum recoveries for selected metabolites of alcohol intoxication. 5% solution of [tris(hydroxymethyl)methylamino] propanesulfonic acid provided recoveries of formate, oxalate and glycolate close to 100% and only moderate erythrocyte lysis. Both charged and uncharged compounds from the whole blood samples can be analyzed in the separated blood plasma by capillary electrophoresis with contactless conductometric detection and spectrophotometry, respectively. The developed device might find wide application in on-site testing and point-of-care analysis, when only microliter volumes of whole blood are available.

Plasma extraction rate enhancement scheme for a real-time and continuous blood plasma separation device using a sheathless cell concentrator

Microfluidic devices for plasma extraction are popular because they offer the advantage of smaller reagent consumption compared to conventional centrifugations. The plasma yield (volume percentage of plasma that can be extracted) is an important factor for diagnoses in microdevices with small reagent consumptions. However, recently designed microfluidic devices tend to have a low plasma yield because they have been optimized to improve the purity of extracted plasma. Thus, these devices require large amounts of reagents, and this complexity has eliminated the advantage of microfluidic devices that can operate with only small amounts of reagents. We therefore propose a continuous, real-time, blood plasma separation device, for plasma extraction rate enhancements. Moreover, a blood plasma separation device was designed to achieve improved plasma yields with high-purity efficiency. To obtain a high plasma yield, microstructures were placed on the bottom side of the channel to increase the concentration of blood cells. Plasma separation was then accomplished via microfluidic networks based on the Zweifach–Fung effect. The proposed device was fabricated based on the polydimethylsiloxane molding process using the SU-8 microfluidic channel for the fabrication of the mold and bottom structures. Human blood diluted in a phosphate buffered saline solution (25% hematocrit) was injected into the inlet of the device. The purity efficiencies were approximately equal to 96% with a maximum of 96.75% at a flow rate of 2 µl min−1, while the plasma yield was approximately 59% with a maximum of 59.92% at a flow rate of 4 µl min−1. Compared to results obtained using other devices, our proposed device could obtain comparable or higher plasma purity and a high plasma yield.

Capillary flow-driven microfluidic device with wettability gradient and sedimentation effects for blood plasma separation

We report a capillary flow-driven microfluidic device for blood-plasma separation that comprises a cylindrical well between a pair of bottom and top channels. Exposure of the well to oxygen-plasma creates wettability gradient on its inner surface with its ends hydrophilic and middle portion hydrophobic. Due to capillary action, sample blood self-infuses into bottom channel and rises up the well. Separation of plasma occurs at the hydrophobic patch due to formation of a ‘self-built-in filter’ and sedimentation. Capillary velocity is predicted using a model and validated using experimental data. Sedimentation of RBCs is explained using modified Steinour’s model and correlation between settling velocity and liquid concentration is found. Variation of contact angle on inner surface of the well is characterized and effects of well diameter and height and dilution ratio on plasma separation rate are investigated. With a well of 1.0 mm diameter and 4.0 mm height, 2.0 μl of plasma was obtained (from <10 μl whole blood) in 15 min with a purification efficiency of 99.9%. Detection of glucose was demonstrated with the plasma obtained. Wetting property of channels was maintained by storing in DI water under vacuum and performance of the device was found to be unaffected over three weeks.

Portable, Constriction-Expansion Blood Plasma Separation and Polymerization-Based Malaria Detection.

A portable, microfluidic blood plasma separation device is presented featuring a constriction-expansion design, which produces 100.0% purity for undiluted blood at 9% yield. This level of purity represents an improvement of at least 1 order of magnitude with increased yield compared to that achieved previously using passive separation. The system features high flow rates, 5-30 μL/min plasma collection, with minimal clogging and biofouling. The simple, portable blood plasma separation design is hand-driven and can easily be incorporated with microfluidic or laboratory scale diagnostic assays. The separation system was applied to a paper-based diagnostic test for malaria that produced an amplified color change in the presence of Plasmodium falciparum histidine-rich protein 2 at a concentration well below clinical relevancy for undiluted whole blood.

Numerical optimization and inverse study of a microfluidic device for blood plasma separation

In this paper, a passive microfluidic device for continuous real time blood plasma separation has been studied and optimized. A numerical model is used to solve both the fluid flow and the particles confined within it. Red blood cells are considered as particles with diameter of 7μm. A parametric study is performed in order to characterize the effect of different parameters on separation and purity efficiency. In this study, four different variables were introduced to design the microfluidic device for blood plasma separation including: the angle between the daughter channels and the main channel, the widths, the diffuse angle and the number of daughter channels. Results show that the separation and purity efficiency have an opposite trend. Since finding the optimal design, where both separation and purity efficiency are desirable, was the goal of this research, an optimization is performed by means of Pattern Search algorithm including all the variables. By means of optimization, it is shown that the performance of device can be improved considerably. Optimal design with separation efficiency of 83% and purity efficiency of 85% is achieved. Moreover, an inverse study has been done to calculate the design variables based on the desired separation and purity efficiency. According to related research, separation and purity efficiency were set to (40%, 53%) and (25%, 100%). Design variables were obtained with less than 1% and 4% error, respectively.

Hemolysis-free blood plasma separation.

Hemolysis, involving the rupture of red blood cells (RBCs) and release of their contents into blood plasma, is a major issue of concern in clinical fields. Hemolysis in vitro can occur as a result of errors in clinical trials; in vivo, hemolysis can be caused by a variety of medical conditions. Blood plasma separation is often the first step in blood-based clinical diagnostic procedures. However, inhibitors released from RBCs due to hemolysis during plasma separation can lead to problems in diagnostic tests such as low sensitivity, selectivity and inaccurate results. In particular, a general lack of simple and reliable blood plasma separation methods has been a major obstacle for microfluidic-based point-of-care (POC) diagnostic devices. Here we present a hemolysis-free microfluidic blood plasma separation platform. A membrane filter was positioned on top of a vertical up-flow channel (filter-in-top configuration) to reduce clogging of RBCs by gravity-assisted cells sedimentation. With this device, separated plasma volume was increased approximately 4-fold (2.4 μL plasma after 20 min with 38% hematocrit human whole blood), and hemoglobin concentration in separated plasma was decreased approximately 90% due to the prevention of RBCs hemolysis, when compared to conventional filter-in-bottom configuration blood plasma separation platforms. On-chip plasma contained ~90% of protein and ~100% of nucleic acids found in off-chip centrifuged plasma, confirming comparable target molecule recovery efficiency. This simple and robust on-chip blood plasma separation device integrates with downstream detection modules to ultimately create sample-to-answer microfluidic POC diagnostics devices.

Development of Bioanalytical Techniques Using Micro- and Nanostructures for Medical Applications

Micro- and nanobiodevices, which utilize micro- and nanospace corresponding in size to various biomolecules, are currently accelerating research on medical diagnosis and regenerative medicine. Moreover, novel analytical techniques beyond the past limitations are developed utilizing micro- and nanospace and are achieving an innovation from basic research to clinical diagnosis and therapy. We have developed nanopillar and nanowall array structures for a single molecule measurement and separation sciences, and then, demonstrated unique analytical techniques specific to a precisely defined nanospace. Physicochemical and biological approaches were adopted to understand nanofluidics in these nanospaces and interesting phenomena were found. We are also trying to transfer these micro- and nanodevices to clinical practices. Some examples such as a blood plasma separation device, a therapeutic drug monitoring device, an immuno-pillar device for high-speed and high-sensitivity cancer and disease markers are described in this paper.

Microfluidic chip with serially connected filters for improvement of collection efficiency in blood plasma separation

This paper describes a novel microfluidic chip, including implementation of serially connected filters for improvement of collection efficiency in blood plasma separation. We have previously reported on a blood plasma separation device, comprising serially connected filters, and its effect on plasma collection efficiency. This paper describes improvement of the device structure for biological blood separation and integration of the filters into a microfluidic chip. Plasma collection into an outer reservoir enables use of the separated plasma in further processing, although the ultimate objective is on-chip analysis of plasma constituents, this is not currently possible. Thus, a collection mechanism for the serially connected filters was also developed and implemented. The device developed in this study was able to extract approximately 4 μL of plasma from 50 μL of non-diluted whole blood into an outer reservoir without critical hemolysis. The successfully miniaturized filter device was able to collect both plasma and un-separated blood into outer reservoirs for further processing and will be a useful separation platform for μTAS applications.

Laboratory evaluation of blood plasma separation device in children

Laboratory evaluation of blood plasma separation device in children

Large-Volume Centrifugal Microfluidic Device for Blood Plasma Separation

Microfluidic-based systems are ideal for handling small microliter volumes of samples and reagents, but 'real-world' or clinical samples for bioanalysis are often on the milliliter scale. We aimed to develop and validate a large-volume centrifugal or compact disc-based device for blood plasma separation, capable of processing 2 ml undiluted blood samples. This automated blood sample preparation device was shown to yield high purity plasma in less than half the time of commercial plasma preparation tubes, while enabling integration with downstream analysis and detection steps. This article draws upon a novel large-volume device to further illustrate the challenges in combining microfluidics structures with large-volume samples and the implications for sample-driven microfluidics systems.

High flow rate microfluidic device for blood plasma separation using a range of temperatures

A hybrid microfluidic device that uses hydrodynamic forces to separate human plasma from blood cells has been designed and fabricated and the advantageous effects of temperature and flow rates are investigated in this paper. The blood separating device includes an inlet which is reduced by approximately 20 times to a small constrictor channel, which then opens out to a larger output channel with a small lateral channel for the collection of plasma. When tested the device separated plasma from whole blood using a wide range of flow rates, between 50 microl min(-1) and 200 microl min(-1), at the higher flow rates injected by hand and at temperatures ranging from 23 degrees C to 50 degrees C, the latter resulting in an increase in the cell-free layer of up to 250%. It was also tested continuously using between 5% and 40% erythrocytes in plasma and whole blood without blocking the channels or hemolysis of the cells. The mean percentage of plasma collected after separation was 3.47% from a sample of 1 ml. The percentage of cells removed from the plasma varied depending on the flow rate used, but at 37 degrees C ranged between 95.4 +/- 1% and 97.05 +/- 05% at 100 microl min(-1) and 200 microl min(-1), respectively. The change in temperature also had an effect on the number of cells removed from the plasma which was between 93.5 +/- 0.65% and 97.01 +/- 0.3% at 26.9 degrees C and 37 degrees C, respectively, using a flow rate of 100 microl min(-1). Due to its ability to operate in a wide range of conditions, it is envisaged that this device can be used in in vitro 'lab on a chip' applications, as well as a hand-held point of care (POC) device.

A microfluidic device for continuous, real time blood plasma separation

A microfluidic device for continuous, real time blood plasma separation is introduced. The principle of the blood plasma separation from blood cells is supported by the Zweifach-Fung effect and was experimentally demonstrated using simple microchannels. The blood plasma separation device is composed of a blood inlet, a bifurcating region which leads to a purified plasma outlet, and a concentrated blood cell outlet. It was designed to separate blood plasma from an initial blood sample of up to 45% inlet hematocrit (volume percentage of cells). The microfluidic network was designed using an analogous electrical circuit, as well as analytical and numerical studies. The functionality of this device was demonstrated using defibrinated sheep blood. During 30 minutes of continuous blood infusion through the device, all the erythrocytes (red blood cells) traveled through the device toward the concentrated blood outlet while only the plasma was separated at the bifurcating regions and flowed towards the plasma outlet. The device has been operated continuously without any clogging or hemolysis of cells. The experimentally determined plasma selectivity with respect to blood hematocrit level was almost 100% regardless of the inlet hematocrit. The total plasma separation volume percent varied from 15% to 25% with increasing inlet hematocrit. Due to the device's simple structure and control mechanism, this microdevice is expected to be used for highly efficient continuous, real time cell-free blood plasma separation from blood samples for use in lab on a chip applications.