Blood Plasma Extracts Research Articles

A Comparative Analysis of the Antioxidant Profiles Generated by the RoXstaTM System for Diverse Biological Fluids Highlights the Powerful Protective Role of Human Seminal Plasma

(1) Background: The RoXstaTM system has been developed as a rapid, effective means of profiling different types of antioxidant activity. The purpose of this study was to examine its performance utilizing a diverse array of biological fluids including semen, blood plasma, serum, urine, saliva, follicular fluid and plant extracts. (2) Methods: The RoXstaTM system was used to assess the ability of different fluids to suppress free radical formation as well as scavenge a variety of toxic oxygen metabolites including free radicals and both hydrogen and organic peroxides. (3) Results: Human semen was shown to have significantly (p < 0.001) more peroxide scavenging power than any other fluid tested (10–14 mM vitamin C equivalent compared with 1–2 mM for blood serum or plasma), while urine was particularly effective in scavenging free radicals and preventing free radical formation (p < 0.001). The powerful antioxidant properties of human semen were shown to reside within the seminal plasma (SP) fraction, rather than the spermatozoa, and to be resistant to snap freezing in liquid nitrogen. Moreover, comparative studies demonstrated that human SP exhibited significantly (p < 0.001) higher levels of antioxidant potential than any other species examined (stallion, bull, dog) and that this intense activity reflected the relative vulnerability of human spermatozoa to peroxide attack. (4) Conclusions: The RoXstaTM system provides valuable information on the antioxidant profile of complex biological fluids, supporting its diagnostic role in conditions associated with oxidative stress. Based on the results secured in this study, human semen is identified as a particularly rich source of antioxidants capable of scavenging both hydrogen and organic peroxides, in keeping with the high susceptibility of human spermatozoa to peroxide-mediated damage.

Impact of a legumes diet on the human gut microbiome articulated with fecal and plasma metabolomes: A pilot study

Background & AimsLegumes intake is known to be associated with several health benefits the origins of which is still a matter of debate. This paper addresses a pilot small cohort to probe for metabolic aspects of the interplay between legumes intake, human metabolism and gut microbiota. MethodsUntargeted nuclear magnetic resonance (NMR) metabolomics of blood plasma and fecal extracts was carried out, in tandem with qPCR analysis of feces, to assess the impact of an 8-week pilot legumes diet intervention on the fecal and plasma metabolomes and gut microbiota of 19 subjects. ResultsWhile the high inter-individual variability hindered the detection of statistically significant changes in the gut microbiome, increased fecal glucose and decreased threonine levels were noted. Correlation analysis between the microbiome and fecal metabolome lead to putative hypotheses regarding the metabolic activities of prevalent bacteria groups (Clostridium leptum subgroup, Roseburia spp., and F. prausnitzii). These included elevated fecal glucose as a preferential energy source, the involvement of valerate/isovalerate and reduced protein degradation in gut microbiota. Plasma metabolomics advanced mannose and betaine as potential markers of legume intake and unveiled a decrease in formate and ketone bodies, the latter suggesting improved energy utilization through legume carbohydrates. Amino acid metabolism was also apparently affected, as suggested by lowered urea, histidine and threonine levels. ConclusionsDespite the high inter-individual gut microbiome variability characterizing the small cohort addressed, combination of microbiological measurements and untargeted metabolomics unveiled several metabolic effects putatively related to legumes intake. If confirmed in larger cohorts, our findings will support the inclusion of legumes in diets and contribute valuable new insight into the origins of associated health benefits.

Development and Validation of Bioanalytical Method for Estimation of Rivaroxaban using RP-HPLC with Liquid liquid extraction in Human Blood Plasma and its application in Bioequivalence Study

Rivaroxaban is andirect acting oralanticoagulant and factor Xa inhibitor. A simple, selective, precise and rapid RP-HPLC method for estimation of Rivaroxaban (RIVA) in human blood plasma was developed and validated. The sample spike in plasma was extracted using liquid liquid extraction were extracted with the organic solvent ethyl acetate as organic solvent. Apixaban as an internal standard. The compounds were analysed by Agilent HPLC was used with control panel software using UV detector on a Inertsil ODS (250mm x 4.6mm ID;5μ) column with an Flow rate of 1.2mL/min, an isocratic mobile phase consisting of 0.02M Ammonium acetate buffer: Acetonitrile (70:30%v/v). Different sample pre-treatment techniques were evaluated, but Liquid Liquid extraction was found to be satisfactory, with good recovery values of 93.70% for RIVA. The developed method is validated by ICHM10 and USFDA guidelines over the concentration range of 5.00 to 200.00 ng/ml in human blood plasma with R² =0.9993. Within-day precisions and accuracy for RIVA were found in 0.36% to 4.73% and 92.58% to101.82% respectively. The validated RP-HPLC method has been used successfully for both preliminary pharmacokinetic studies and therapeutic drug monitoring

High-Throughput Blood Plasma Extraction in a Dimension-Confined Double-Spiral Channel

High-Throughput Blood Plasma Extraction in a Dimension-Confined Double-Spiral Channel

Engineering an extremely high flow rate micropump and integrating with an inertial microfluidics for rapid and efficient blood plasma extraction from fingertip blood with lancets

Extracting blood plasma is a necessary step for many medical diagnostics, and inertial microfluidics has attracted significant attention in separating plasma and blood cells from blood. However, external pump was mandatorily needed to generate sufficient flow rate and inertial effect to achieve the separation performance, which led to requirement of blood in mL scale due to the connectors and tubings from the external pump to the microfluidics. An integrated microfluidics was developed herein to rapidly extract blood plasma from only 4 μL whole blood drawn from fingertip with lancet, which included a highly efficient pneumatic peristaltic micropump (PPM) and a spiral inertial microfluidics with trapezoidal cross-sectional areas. Experiment results clearly demonstrated: (1) blood plasma can be rapidly extracted within 3 minutes with efficiency up to 97% from 45X diluted blood, (2) an extremely high flow rate of 3,500 μL/min was recorded with our triple PPM under applied pressure of 300 kPa and operation frequency of 10 Hz, which is competitive to the current commercial external syringe pump, (3) sufficient applied pressure is critical to the performance of PPM, because it can maintain the efficient stroke volume while minimizing the dead volume during iterative pumping process.

The role of NMDA glutamate receptors in lung injury caused by chronic long-term intermittent hypobaric hypoxia

Chronic intermittent hypoxia (CIH), a component of sleep apnea-hypopnea syndrome, is suggested to cause damage to lung tissue, and the role of glutamate is not well studied. We used a chronic long-term intermittent hypobaric hypoxia (CLTIHH) model of rats to find out if such procedure causes lung injury and the potential effect of N-methyl-D-aspartate receptors (NMDARs) by using receptor antagonist MK-801 (dizocilpine). Thirty-two rats were placed into four groups; a control and three CLTIHH groups where rats were placed into a low-pressure chamber set to 430 mmHg for 5 h/day, 5 days/week, for 5 weeks. Only one group received MK-801 (0.3 mg/kg, ip) daily. We evaluated tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and nuclear factor (NF)-kB for the inflammatory process, superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPX), total antioxidant status (TAS), and total oxidant status (TOS) for oxidative stress, and caspase-9 levels. Blood plasma, bronchoalveolar fluid (BALF), and lung tissue extracts were evaluated. Both oxidant and inflammatory parameters were significantly increased in all the mediums of the CLTIHH groups except the group that received MK-801. Significant evidence was collected on MK-801 alleviating the effect of CLTIHH. Histological evaluations revealed lung damage and fibrotic changes in the CLTIHH groups. It was first shown that the CLTIHH procedure caused chronic lung injury, and that inflammation and oxidant stress were influential in the formation of lung injury. Secondly, NMDAR antagonist MK-801 effectively inhibited the development of lung injury and fibrosis.

Systematic Investigation of LC Miniaturization to Increase Sensitivity in Wide-Target LC-MS-Based Trace Bioanalysis of Small Molecules.

Covering a wide spectrum of molecules is essential for global metabolome assessment. While metabolomics assays are most frequently carried out in microbore LC-MS analysis, reducing the size of the analytical platform has proven its ability to boost sensitivity for specific -omics applications. In this study, we elaborate the impact of LC miniaturization on exploratory small-molecule LC-MS analysis, focusing on chromatographic properties with critical impact on peak picking and statistical analysis. We have assessed a panel of small molecules comprising endogenous metabolites and environmental contaminants covering three flow regimes—analytical, micro-, and nano-flow. Miniaturization to the micro-flow regime yields moderately increased sensitivity as compared to the nano setup, where median sensitivity gains around 80-fold are observed in protein-precipitated blood plasma extract. This gain resulting in higher coverage at low µg/L concentrations is compound dependent. At the same time, the nano-LC-high-resolution mass spectrometry (HRMS) approach reduces the investigated chemical space as a consequence of the trap-and-elute nano-LC platform. Finally, while all three setups show excellent retention time stabilities, rapid gradients jeopardize the peak area repeatability of the nano-LC setup. Micro-LC offers the best compromise between improving signal intensity and metabolome coverage, despite the fact that only incremental gains can be achieved. Hence, we recommend using micro-LC for wide-target small-molecule trace bioanalysis and global metabolomics of abundant samples.

A Modification of the ABTS• Decolorization Method and an Insight into Its Mechanism

A modification of the ABTS• decolorization assay for plate readers is presented. In our modification, 200 µL of ABTS solution of absorbance 1.0 at 734 nm was added with an antioxidant and decreased absorbance resulted. For comparison of antioxidant activities in the kinetic assay of absorbance decrease, concentration dependence of absorbance decrease and of area under curve are recommended. “Fast” and “slow” antioxidants were distinguished: while the reactions of “fast” antioxidants ABTS• were completed within seconds, the reactions of “slow” antioxidants were not finished after 6 min. We recommend reaction time of 60 min for assays of such antioxidants, blood plasma and plant extracts. Sub-additive interactions between some antioxidants (ascorbate and Trolox, hispidulin and Trolox, and glutathione and ascorbate) were found in the ABTS• decolorization; possible reasons for such interactions are discussed.

Synthesis and Investigation of Novel CHCA-Derived Matrices for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric Analysis of Lipids.

A significant area of study and upgrading for increasing sensitivity and general performances of matrix-assisted laser-desorption ionization (MALDI) mass spectrometry (MS) is related to matrix design. Several efforts have been made to address the challenge of low-mass-region interference-free for metabolomics analysis and specifically for lipidomics. To this aim, rationally designed matrices as 4-chloro-α-cyanocinnamic acid (ClCCA) were introduced and reported to provide enhanced analytical performances. We have taken this rational design one step further by developing and optimizing new MALDI matrices with a range of modifications on the CHCA core, involving different functionalities and substituents. Of particular interest was the understanding of the electron-withdrawing (e.g., nitro-) or donating (e.g., methoxy-) effects along with the extent of conjugation on the ionization efficiency. In the present work, ten matrices were designed on a reasonable basis, synthesized, and characterized by NMR and UV spectroscopies and laser desorption ionization. With the assistance of these putative MALDI matrices, samples containing phospholipids (PL), and neutral di-/tri-acylglycerols (DAG, TAG) were investigated using milk, fish, blood, and human plasma extracts. In comparison with CHCA and ClCCA, four of them, viz. [(2E,4E)-2-cyano-5-(4-methoxyphenyl)penta-2,4-dienoic acid] (1), [(2E,4E)-2-cyano-5-(4-nitrophenyl)penta-2,4-dienoic acid] (2), [(E)-2-cyano-3-(6-methoxynaphthalen-2-yl)acrylic acid] (6) and [(E)-2-cyano-3-(naphthalen-2-yl)acrylic acid] (7) displayed good to even excellent performances as MALDI matrices in terms of ionization capability, interference-free spectra, S/N ratio, and reproducibility. Especially compound 7 (cyano naphthyl acrylic acid, CNAA) was the election matrix for PL analysis and matrix 2 (cyano nitrophenyl dienoic acid, CNDA) for neutral lipids such as DAG and TAG in positive ion mode.

Enhanced Blood Plasma Extraction Utilising Viscoelastic Effects in a Serpentine Microchannel.

Plasma extraction from blood is essential for diagnosis of many diseases. The critical process of plasma extraction requires removal of blood cells from whole blood. Fluid viscoelasticity promotes cell migration towards the central axis of flow due to differences in normal stress and physical properties of cells. We investigated the effects of altering fluid viscoelasticity on blood plasma extraction in a serpentine microchannel. Poly (ethylene oxide) (PEO) was dissolved into blood to increase its viscoelasticity. The influences of PEO concentration, blood dilution, and flow rate on the performance of cell focusing were examined. We found that focusing performance can be significantly enhanced by adding PEO into blood. The optimal PEO concentration ranged from 100 to 200 ppm with respect to effective blood cell focusing. An optimal flow rate from 1 to 15 µL/min was determined, at least for our experimental setup. Given less than 1% haemolysis was detected at the outlets in all experimental combinations, the proposed microfluidic methodology appears suitable for applications sensitive to haemocompatibility.

Filtration-assisted magnetofluidic cartridge platform for HIV RNA detection from blood.

The ability to detect and quantify HIV RNA in blood is essential to sensitive detection of infections and monitoring viremia throughout treatment. Current options for point-of-care HIV diagnosis (i.e. lateral flow rapid tests) lack sensitivity for early detection and are unable to quantify viral load. HIV RNA diagnostics typically require extensive pre-processing of blood to isolate plasma and extract nucleic acids, in addition to expensive equipment for conducting nucleic acid amplification and fluorescence detection. Therefore, molecular HIV diagnostics is still mainly limited to clinical laboratories and there is an unmet need for high sensitivity point-of-care screening and at-home HIV viral load quantification. In this work, we outline a streamlined workflow for extraction of plasma from whole blood coupled with HIV RNA extraction and quantitative polymerase chain reaction (qPCR) in a portable magnetofluidic cartridge platform for use at the point-of-care. Viral particles were isolated from blood using manual filtration through a 3D-printed filter module in seconds followed by automated nucleic acid capture, purification, and transfer to qPCR using magnetic beads. Both nucleic acid extraction and qPCR were integrated within cartridges using compact instrumentation consisting of a motorized magnet arm, miniaturized thermocycler, and image-based fluorescence detection. We demonstrated detection down to 1000 copies of HIV viral particles from whole blood in <30 minutes.

Prolonged efavirenz exposure reduces peripheral oxytocin and vasopressin comparable to known drugs of addiction in male Sprague Dawley rats.

IntroductionSeveral drugs of abuse (DOA) are capable of modulating neurohypophysial hormones, such as oxytocin (OT) and vasopressin (VP), potentially resulting in the development of psychological abnormalities, such as cognitive dysfunction, psychoses, and affective disorders. Efavirenz (EFV), widely used in Africa and globally to treat HIV, induces diverse neuropsychiatric side effects while its abuse has become a global concern. The actions of EFV may involve neurohypophysial system (NS) disruption like that of known DOA. This study investigated whether sub-chronic EFV exposure, at a previously-determined rewarding dose, alters peripheral OT and VP levels versus that of a control, ∆9-tetrahydrocannabinol (∆9-THC), methamphetamine (MA) and cocaine.Materials and methodsTo simulate the conditions under which reward-driven behavior had previously been established for EFV, male Sprague Dawley rats (n = 16/exposure) received intraperitoneal vehicle (control) or drug administration across an alternating sixteen-day dosing protocol. Control administration (saline/olive oil; 0.2 ml) occurred on odd-numbered and drug administration (EFV: 5 mg/kg, ∆9-THC: 0.75 mg/kg, MA: 1 mg/kg, or cocaine: 20 mg/kg) on even-numbered days followed by euthanasia, trunk blood collection and plasma extraction for neuropeptide assay. Effect of drug exposure on peripheral OT and VP levels was assessed versus controls and quantified using specific ELISA kits. Statistical significance was determined by Kruskal-Wallis ANOVA, with p < 0.05. Ethics approval: NWU-00291-17-A5.ResultsDelta-9-THC reduced OT and VP plasma levels (p < 0.0001, p = 0.0141; respectively), cocaine reduced plasma OT (p = 0.0023), while MA reduced plasma VP levels (p = 0.0001), all versus control. EFV reduced OT and VP plasma levels (p < 0.0001; OT and VP) versus control, and similar to ∆9-THC.ConclusionEFV markedly affects the NS in significantly reducing both plasma OT and VP equivalent to DOA. Importantly, EFV has distinct effects on peripheral OT and VP levels when assessed within the context of drug dependence. The data highlights a possible new mechanism underlying previously documented EFV-induced effects in rats, and whereby EFV may induce neuropsychiatric adverse effects clinically; also providing a deeper understanding of the suggested abuse-potential of EFV.

Blood Plasma Separation: Enhanced Diamagnetic Repulsion of Blood Cells Enables Versatile Plasma Separation for Biomarker Analysis in Blood (Small 23/2021)

In article 2100797, Joo H. Kang, and co-authors present a new blood plasma extraction device using augmented diamagnetic repulsion of blood cells by supplementing superparamagnetic iron oxide nanoparticles to whole blood and demonstrate its utility for various biomarker analysis, such as prostate-specific antigen, platelets, exosomes, and nucleic acids, in whole blood without prior blood plasma separation.

The effect of combaine administration of L-arginine and omega-3 polyunsaturated fatty acids on the spectrum of free amino acids and biogen amines in hyppocampus of rats undergoing subtotal cerebral ischemia

The aim of this study was to estimate the changes in the pool of free amino acids and their derivatives in hippocampus of rats undergoing subtotal cerebral ischemia (SCI) and treated with L-arginine and omega-3 polyunsaturated fatty acids (PUFA). Experiment was held on 18 rats: 12 animals were undergoing bilateral filament occlusion of arteries carotid, 6 of them L-arginine and omega-3 PUFA was administrated. The drug omega-3 PUFA "Omegamed" (at a dose of 5 g/kg of body weight) was injected intragastrically during the week preceding the simulation of SIMG. L-arginine (at a dose of 100 mg/kg body weight) was injected intravenously just before ligation of the common carotid arteries. The analyses of free amino acids and their derivates levels in the blood plasma extracts were carried out by reversed phase HPLC. In the hippocampus of rats with SIGM, there was an increase in the levels of histidine, 3-methylhistidine, glutamine, α--aminobutyrate, isoleucine, leucine, valine, as well as a decrease in the levels of threonine, tyrosine, and α--aminoadipic acid. Administration of L-arginine and omega-3 PUFAs prevented ischemia-induced disruption of threonine, histidine, glutamine, α--aminobutyrate, α--aminoadipic acid levels, and also had a corrective effect on the serotonin system of the hippocampus.

Multi-residue analysis of pesticides in blood plasma using hollow fiber solvent bar microextraction and gas chromatography with a flame ionization detector

The challenges faced on pesticide extraction from biological samples are finding a method that allows a multi-residue extraction, pre-concentration, clean-up, and isolation of analytes in just one step. In this sense, the hollow fiber – liquid phase microextraction method (HF- LPME) in the "solvent bar" mode was used to optimize and validate a method for pesticide multi-residue analysis in blood plasma at trace levels, through gas chromatography coupled with a flame ionization detector (GC-FID). Hollow fiber solvent bar microextraction HF-SBME was carried out with octanol immobilized into the pores of hydrophobic polypropylene fiber and disposed within a matrix of blood plasma, spiked with a mixture of pesticides (monocrotophos, lindane, aldrin, methyl parathion, endosulfan, dieldrin, DDD, DDT, and endrin). The optimization parameters evaluated were: extraction temperature and time, stirring speed, and salt concentration. A principal component analysis was performed to visualize the analytes' behaviour based on their explained variance, and then, a Box-Behnken analysis was generated to identify the optimum parameters. According to the PCA, all pesticides showed similar responses to the extraction method and the response of dieldrin exhibit the lowest variance. Moreover, the stationary points selected from the Box-Behnken analysis were 25.5 °C for the extraction temperature, 870 rpm for stirring speed, 16 min for extraction time, and 8.3 % w/v of salt concentration. Moreover, the validation results proved that HF-SBME is an alternative technique for pesticide multi-residue extraction in blood plasma. The analytes were able to concentrate, reaching 46 fold enrichment. The solvent type, sample and solvent volume were narrowed down without changing the method's precision or accuracy. The relative standard deviation was under 10 %, and the recovery was between 55 % and 105 % for the different analytes excepting lindane, which had lower recovery (27 %). The detection limits were 0.02 until 0.13 μg mL−1 for most of the pesticides used. Finally, HF-SBME is a good alternative for pesticide multi-residue extraction in complex matrices like plasma.

Structural Elucidation of Ether Glycerophospholipids Using Gas-Phase Ion/Ion Charge Inversion Chemistry.

Ether lipids represent a unique subclass of glycerophospholipid (GPL) that possesses a 1-O-alkyl (i.e., plasmanyl subclass) or a 1-O-alk-1'-enyl (i.e., plasmenyl subclass) group linked at the sn-1 position of the glycerol backbone. As changes in ether GPL composition and abundance are associated with numerous human pathologies, analytical strategies capable of providing high-level structural detail are desirable. While mass spectrometry (MS) has emerged as a prominent tool for lipid structural elucidation in biological extracts, distinctions between the various isomeric forms of ether-linked GPLs have remained a significant challenge for tandem MS, principally due to similarities in the conventional tandem mass spectra obtained from the two ether-linked subclasses. To distinguish plasmanyl and plasmenyl GPLs, a multistage (i.e., MSn where n = 3 or 4) mass spectrometric approach reliant on low-energy collision-induced dissociation (CID) is required. While this method facilitates assignment of the sn-1 bond type (i.e., 1-O-alkyl versus 1-O-alk-1'-enyl), a composite distribution of isomers is left unresolved, as carbon-carbon double-bond (C=C) positions cannot be localized in the sn-2 fatty acyl substituent. In this study, we combine a systematic MSn approach with two unique gas-phase charge inversion ion/ion chemistries to elucidate ether GPL structures with high-level detail. Ultimately, we assign both the sn-1 bond type and sites of unsaturation in the sn-2 fatty acyl substituent using an entirely gas-phase MS-based workflow. Application of this workflow to human blood plasma extract permitted isomeric resolution and in-depth structural identification of major and, in some cases, minor isomeric contributors to ether GPLs that have been previously unresolved when examined via conventional methods.

Effect of blockade of synthesis of nitric oxide by L-NAME on the level of free amino acids and biogenic amines in the brain cortex of rats with subtotal cerebral ischemia

Mechanisms of development of ischemic stroke are complex and have not been fully established. The aim of this study was to estimate the changes in the pool of free amino acids and biogenic animes in the brain cortex of rats with subtotal cerebral ischemia (SCI) and treated with L-NAME. Experiment was made on 18 rats: 12 animals were undergoing bilateral filament occlusion of arteries carotid, 6 of them were treated with L-NAME. The analyses of free amino acids levels in the blood plasma extracts were carried out by reversed phase HPLC.Concentrations of several amino acids were elevated during SCI including aspartate, b-alanine, valine and leucine. In contrast, the levels of glutamate, asparagine, treonine, gamma-aminobutiric acid, tyrosine and 5-hydroxiindolylacetate were decreased. The administration of L-NAME partially prevented the imbalance of the amino acids pool due to SCI by normalizing the levels of aspartate, glutamate, asparagine, methionine, gamma-aminobutiric acid, b-alanine, 5-hydroxiindolylacetate. However, the administration of L-NAME has induced an additional imbalance in the amino acids pool in the brain cortex (decrease in the levels of glutamine, histidine, taurine, tryptophan, phenylalanine, tyrosine (in comparison to SCI) and decrease in the levels of treonine and arginine. The imbalance of the amino acids pool induced by the administration of L-NAME during SCI is more severe than the imbalance caused by SCI.

Pool of free amino acids in the blood plasma of rats undergoing subtotal cerebral ischemia after L-name administration

A stroke is one of the leading causes of morbidity, disability and mortality in many countries. Mechanisms of development of ischemic stroke are complex and have not been fully established. The aim of this study was to estimate the changes in the pool of free amino acids and their derivatives in the plasma of rats undergoing subtotal cerebral ischemia (SCI) and treated with L-NAME. Experiment was made on 18 rats: 12 animals were undergoing bilateral flament occlusion of arteries carotid, 6 of them were treated with L-NAME. The analyses of free amino acids levels in the blood plasma extracts were carried out by reversedphase HPLC. Concentrations of several amino acids were elevated after 1 hour of ischemia, including aspartate, asparagine, glutamine, glycin, alanine, taurine, phenylalanine, gistidine, 3-methilgistidine, treonine, citrulline, ornitine, as well as branched-chain amino acids. Administration of L-NAME partially prevented the imbalance of the amino acids pool caused by SCI. Preventive injection of L-NAME alleviated the imbalance in the pool of free amino acids of blood plasma caused by SCI.

Ultra-low aspect ratio spiral microchannel with ordered micro-bars for flow-rate insensitive blood plasma extraction

The ability to regulate secondary flow is significant for efficient particle/cell focusing. Microfluidic technologies have accomplished impressive progress in particle/cell manipulation with the help of the Dean effect. Herein, we explored blood cell focusing with the ultra-low aspect ratio inertial microfluidic system which uses the geometric confinement to enhance the secondary flows to different degrees. Introducing a series of micro-bars in the spiral microchannels accelerates the secondary flow, which can greatly enhance highly-efficient particle/cell focusing under various flow rates. Further, plasma extraction can be successfully achieved from 15× diluted whole blood in an easy-to-use (without the assistance of sheath fluid and complex manufacturing of multi-layer structure), high and wide flow rates (1–5 mL/min, exhibiting no parallel construction design), long-term (at least 60 min), stable (processing at least 300 mL blood samples with consistent efficiency), and highly-efficient (99.99% blood cell rejection ratio) manner. Compared with previously-reported technologies, the engineering strategy of secondary flow in our designed dimension-confined spiral channel provides a balanced overall performance for plasma separation pointing to ease-to-fabrication, insensitive to flow-rate, high throughput and operation efficiency.

A carbon nanotube integrated microfluidic device for blood plasma extraction

Blood is a complex fluid consisting of cells and plasma. Plasma contains key biomarkers essential for disease diagnosis and therapeutic monitoring. Thus, by separating plasma from the blood, it is possible to analyze these biomarkers. Conventional methods for plasma extraction involve bulky equipment, and miniaturization constitutes a key step to develop portable devices for plasma extraction. Here, we integrated nanomaterial synthesis with microfabrication, and built a microfluidic device. In particular, we designed a double-spiral channel able to perform cross-flow filtration. This channel was constructed by growing aligned carbon nanotubes (CNTs) with average inter-tubular distances of ~80 nm, which resulted in porosity values of ~93%. During blood extraction, these aligned CNTs allow smaller molecules (e.g., proteins) to pass through the channel wall, while larger molecules (e.g., cells) get blocked. Our results show that our device effectively separates plasma from blood, by trapping blood cells. We successfully recovered albumin -the most abundant protein inside plasma- with an efficiency of ~80%. This work constitutes the first report on integrating biocompatible nitrogen-doped CNT (CNxCNT) arrays to extract plasma from human blood, thus widening the bio-applications of CNTs.