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In this paper, we report a point-of-care (POCT) testing strip based on a porous membrane structure for whole blood separation and colorimetric analysis without external supporting equipment. Conventional blood tests rely on large instruments for blood pretreatment and separation to improve measurement accuracy. Cellulose acetate (CA) membranes with different pore diameters and structures were prepared via a non-solvent method for the separation of whole blood. Among them, CA@PEG-2000 membranes with nano-pores on the surface and micro-pores in the interior facilitated the capture of blood cells on the surface, as well as the free diffusion of plasma through the porous interior structure. The fluid flow of blood in the asymmetric porous structure can be theoretically estimated using the Lucas-Washburn equation. Compared with the conventional paper strips and other porous membranes, the CA@PEG-2000 membrane with an immobilized sensing layer exhibited efficient blood separation, a short response time (less than 2 min), an ultralow dosage volume (5 μL), and high sensitivity. The fabricated blood separation membranes can be further used for the detection of various biomarkers in whole blood, providing additional options for rapid quantitative POCT tests.

Objective: To investigate the evolution of blood separation results by gel extraction of multiple myeloma (MM) patients, and to evaluate the clinical value of abnormal blood separation results for the evaluation of disease and prognosis., Methods: The clinical data of 5 patients diagnosed newly MM patients with abnormal blood separation of gel collection vessels in our hospital were retrospectively analyzed, and the changes of blood separation results and blood index levels were followed up with the improvement of treatment effect, and the correlation of different blood index levels was analyzed., Results: In 5 patients with newly diagnosed MM, the blood separation result showed floating phenomenon after centrifugation, which divided into three layers and the order from top to bottom is separator gel, serum, and red blood cells(RBC). With partial remission of clinical symptoms, the blood separation results were still abnormal, which were divided into three layers from top to bottom: serum, RBC and separator gel. Finally, with complete remission of the disease, blood separation results returned to normal, from top to bottom: serum, separator gel, RBC. With the blood separation results from abnormal to normal, the blood routine indicators: Hb, Hct levels gradually increased, neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR) gradually decreased; biochemical indexes: TP, GLB, Ig and β 2 -MG levels gradually decreased. Tumor load related indicators: serum IL-6, TNF-α, IL-17 levels gradually decreased, and IL-35 levels gradually increased; and the differences were statistically significant (P<0.05). Pearson correlation analysis showed that serum β 2 -MG was positively correlated with IL-6, TNF-α and IL-17 levels (r=0.710, 0.756, 0.581, P<0.05), and negatively correlated with IL-35 level (r=-0565, P<0.05)., Conclusion: Abnormal blood separation exists in MM patients, and there are significant differences in blood, tumor load and immune balance related indexes in patients with different blood separation results, which provides partial experimental basis for evaluation of disease, efficacy and prognosis with different blood separation results.

Objectives: Our objectives were to determine the separation characteristics and blood product quality of a gravity-driven microfiltration blood separation system (HemoClear, The Netherlands)., Background: A range of centrifugal blood separation devices, including intraoperative cell salvage devices (cell savers) and apheresis machines, are available to assist in preparing both allogenic and autologous blood products. These devices are expensive to operate and require extensive training., Methods and Materials: Nine whole blood units were collected under standard conditions and analysed for haematological parameters, thromboelastographic properties, platelet morphology and activation, and red blood cell (RBC) deformability and morphology. Three whole blood units were separated by means of the HemoClear device, into a liquid and cellular component. The cellular component was diluted with SAGM and cold stored for 14 days. To simulate cell salvage six whole blood units were diluted with isotonic saline, followed by multiple HemoClear separation rounds., Results: The recovery of both RBCs (100 ± 1.6%) and white blood cells (99 ± 4.5%) after undiluted filtration were very high, while platelet recovery was high (83 ± 3.0%). During the filtration, and cold storage after filtration storage both the non-deformable RBC fraction and the RBC maximum elongation remained stable. Parameters of thromboelastography indicated that platelets remain functional after filtration and after 7 days of cold storage. In the cell salvage simulation the total protein load in the cellular fraction was reduced by 65 ± 4.1% after one washing round and 84 ± 1.9% after two consecutive washing rounds., Conclusion: The novel blood filter studied effectively separates whole blood into diluted plasma and platelet-rich RBCs. Moreover, the device effectively washed diluted whole blood, driving over 80% of proteins to the liquid component., (© 2021 The Authors. Transfusion Medicine published by John Wiley & Sons Ltd on behalf of British Blood Transfusion Society.)

Separation of blood plasma or serum from blood is essential for accurate analysis. Conventional blood separation requires instrumentation, reagents, and large sample volumes, limiting this process to laboratory environments with trained personnel. Full implementation of effective blood separation and analysis on microliter sample volumes for point of care (POC) diagnostics has proven extremely challenging resulting in a growing market demand, with common challenges such as expensive device fabrication processes or devices being comprised of materials which are not easily disposable. We developed a membrane-based wicking microfluidic device which is made using a simple fabrication process. This device uses a unique 3D flow channel geometry, fabricated in a polycaprolactone-filled glass microfiber membrane, to efficiently separate microliter sample volumes of blood. Colorimetric assay chemistries were integrated to demonstrate utility of these devices in POC diagnostics. The devices are capable of separating both fresh and anticoagulant-treated blood at microscale sample volumes (<15.0 μL). Modifications to the base device are also reported herein which increased sample volume capacity and separation efficiency. Integrated colorimetric assay enabled semi-quantitative detection of conjugated bilirubin in real blood samples (1.0-1.5 mg/dL). These blood separation devices, fabricated on polycaprolactone-filled glass microfiber, enabled effective blood plasma (anticoagulant-treated blood) and serum (fresh blood) separation with microscale sample volumes. Sample volume capacity and separation efficiency are customizable for specific applications and devices can be integrated with downstream assay chemistries to develop complete POC devices that offer blood separation and diagnostics at the same time on a single membrane.

This work introduces the procedure of using non-immunoassay distance-based paper analytical devices (dPADs) to accurately measure any traces of the cardiac troponin I (TnI) in whole blood samples without the use of any external blood separation. This enables a rapid clinical diagnosis and the subsequent follow-up in regard to identifying acute myocardial infarction. These dPADs are designed and constructed to accommodate three parts: (1) a blood separation zone that is immobilized with a hemostatic agent, this no longer requires a blood separation membrane for the isolation of the plasma from the blood element, (2) a pretreatment zone, and (3) a detection zone coated with thymol blue. The quantitative TnI level in the whole blood was determined by measuring the blue color length found in the detection zone, which is proportional to the concentration, owing to the dry protein binding principle. Correspondingly, a mere single drop of human whole blood performs adequately within our proposed method. This reduces both the size of the collection process and the sample volumes needed in the respective medical fields. As we cover all of the optimization studies, our dPADs provide an evaluation of the linearity range from 0.025 to 2.5 ng/mL ( R 2 = 0.9989) of TnI, with a detection limit as low as 0.025 ng/mL by use of an observation just using the naked eye. To validate the clinical utilities of our proposed method, our dPADs were then applied for the detection of TnI in humans using the whole blood sample of 15 volunteers. A great amount of accuracy was required in this assay because there was no significant difference between both methods, with the confidence level being as high as 95%. This technique also showed that the recoveries ranged from 99.40 to 104.27%, with the highest relative standard deviation being at 3.77%. Thus, our proposed dPADs offer more benefits for a rapid TnI determination.

In this paper, we describe two fabrication methods (well array-based and biopsy punching-based) of gel disks to construct a gel-based point-of-care (POC) diagnosis device for direct colorimetric measurement of human whole blood glucose without any extra blood separation step. The gel disks are made of Polyethylene glycol (PEG) diacrylate (PEG-DA) containing immobilized glucose colorimetric assay reagents. The performances of three types of PEG-DA gel (molecular weight: 575, 3,400, and 10,000) based sensors as well as the two fabrication methods were investigated.•The fabricated devices enabled colorimetric whole blood glucose sensing assay without the need for blood cell separation•The biopsy punching-based gel disk fabrication method provided less variation on the fabricated gel disks., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors. Published by Elsevier B.V.)

Dynamic and on-site analysis of serum from human blood is crucial, however, state-of-the-art blood-assay methods can only collect single or discrete data of physiological analytes; thus, the online reports of the dynamic fluctuation of key analytes remains a great challenge. Here, we propose a novel separation-sensing membrane by constructing a heterogeneous-nanostructured architecture, wherein a surface nanoporous layer continuously extracts serum, while the biosensing nanochannels underneath dynamically recognise biotargets, thereby achieving a continuous testing of vital clinical indices as blood is drawn. By precisely controlling the pore structure and nanoshape of biosensing crystals, this membrane achieved accurate and online glucose and lactate monitoring in patients with a variety of medical conditions within 1 min, which is one order of magnitude faster than state-of-the-art techniques. Moreover, various kinds of bio-recognisers can be introduced into this membrane to accurately detect glutamate, transaminase, and cancer biomarkers., (© 2020 Wiley-VCH GmbH.)

A microfluidic chip, which can separate and enrich leukocytes from whole blood, is proposed. The chip has 10 switchback curve channels, which are connected by straight channels. The straight channels are designed to permit the inertial migration effect and to concentrate the blood cells, while the curve channels allow the Dean flow to further classify the blood cells based on the cell sizes. Hydrodynamic suction is also utilized to remove smaller blood cells (e.g., red blood cell (RBC)) in the curve channels for higher separation purity. By employing the inertial migration, Dean flow force, and hydrodynamic suction in a continuous flow system, our chip successfully separates large white blood cells (WBCs) from the whole blood with the processing rates as high as 1 × 10 8 cells/sec at a high recovery rate at 93.2% and very few RBCs (~0.1%)., Competing Interests: The authors declare no conflict of interest.

A microfluidic SERS chip integrated with blood separation and in-situ detection was designed and fabricated for the rapid detection of clinical blood samples. Each functional unit in the microfluidic SERS chip consist of separation-decantation cavity based on centrifugal separation principle, mixing channels and SERS detection chamber built with integrated nano-Au on Ag film microstructure. The serum creatinine was selected as a typical sample to demonstrate the capability of microfluidic SERS chip. It was found that the creatinine SERS characteristic peaks at 678 cm -1 can be effectively identified and the detection limit could be as low as 4.42 × 10 -3 μmol mL -1 in water. The blood samples were also tested in microfluidic SERS chip. The whole separation and test process could be completed within 2 min, which is a significant improvement in the field of creatinine detection. The whole blood of six cases clinical blood samples were also tested, and the results were consistent with the enzymatic results. The developed microfluidic SERS chip has advantages including reduction of the required quantity of blood sample, reusable and easy to operate. It is expected to provide a new method for rapid diagnostics., (Copyright © 2018. Published by Elsevier B.V.)

Neutrophil dysfunction is strongly linked to type 2 diabetes mellitus (T2DM) pathophysiology, but the prognostic potential of neutrophil biomarkers remains largely unexplored due to arduous leukocyte isolation methods. Herein, a novel integrated microdevice is reported for single-step neutrophil sorting and phenotyping (chemotaxis and formation of neutrophil extracellular traps (NETosis)) using small blood volumes (fingerprick). Untouched neutrophils are purified on-chip from whole blood directly using biomimetic cell margination and affinity-based capture, and are exposed to preloaded chemoattractant or NETosis stimulant to initiate chemotaxis or NETosis, respectively. Device performance is first characterized using healthy and in vitro inflamed blood samples (tumor necrosis factor alpha, high glucose), followed by clinical risk stratification in a cohort of subjects with T2DM. Interestingly, "high-risk" T2DM patients characterized by severe chemotaxis impairment reveal significantly higher C-reactive protein levels and poor lipid metabolism characteristics as compared to "low-risk" subjects, and their neutrophil chemotaxis responses can be mitigated after in vitro metformin treatment. Overall, this unique and user-friendly microfluidics immune health profiling strategy can significantly aid the quantification of chemotaxis and NETosis in clinical settings, and be further translated into a tool for risk stratification and precision medicine methods in subjects with metabolic diseases such as T2DM., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A novel device of smart pipette has been suggested to extract and deliver plasma from whole blood in a disposable format. By operating an on-chip disposable micropump, approximately 30 μL of plasma was obtained from 100 μL of whole blood within 5 min without any external equipment for point-of-care blood analysis.

Background: The ErySep system represents an alternative to centrifuge-based whole blood (WB) separation, using gravity and filtration through hollow-fibres (0·2 µm pore size) to produce red blood cell (RBC) and plasma components. The aim of this study was to characterise the quality of ErySep RBC and plasma units compared with standard products from WB held overnight., Methods/materials: Two ABO-compatible WB units (n = 24) were pooled and split to produce matched products. One of the WB units was separated into components using the ErySep system (ErySep; n = 12), whereas the other units were separated by centrifugation (control; n = 12). RBC units were stored at 2-6 °C and assessed for in vitro quality over 42 days of storage. Plasma was frozen at -30 °C and tested upon thawing., Results: Processing WB with the ErySep system took longer than controls. The ErySep RBC units were of an appropriate volume (307 ± 17 mL) and contained sufficient Hb (50 ± 2 g unit(-1) ). ErySep RBC components contained more microparticles relative to controls at expiry. The plasma volume, total protein, coagulation factor activity (fibrinogen, FV, FVIII) and number of microparticles was lower in the ErySep units compared with controls., Conclusion: Following overnight hold of WB, the ErySep system was capable of producing RBC components that met specifications. However, the ErySep plasma components did not meet quality specifications., (© 2015 British Blood Transfusion Society.)

Determining cell mechanical properties is increasingly recognized as a marker-free way to characterize and separate biological cells. This emerging realization has led to the development of a plethora of appropriate measurement techniques. Here, we use a fairly novel approach, deterministic lateral displacement (DLD), to separate blood cells based on their mechanical phenotype with high throughput. Human red blood cells were treated chemically to alter their membrane deformability and the effect of this alteration on the hydrodynamic behaviour of the cells in a DLD device was investigated. Cells of defined stiffness (glutaraldehyde cross-linked erythrocytes) were used to test the performance of the DLD device across a range of cell stiffness and applied shear rates. Optical stretching was used as an independent method for quantifying the variation in stiffness of the cells. Lateral displacement of cells flowing within the device, and their subsequent exit position from the device were shown to correlate with cell stiffness. Data showing how the isolation of leucocytes from whole blood varies with applied shear rate are also presented. The ability to sort leucocyte sub-populations (T-lymphocytes and neutrophils), based on a combination of cell size and deformability, demonstrates the potential for using DLD devices to perform continuous fractionation and/or enrichment of leucocyte sub-populations from whole blood.