Small Volumes Of Whole Blood Research Articles

Microfluidic Digital Immunoassay for Point-of-Care Detection of NT-proBNP from Whole Blood.

The high prevalence and economic burden of heart failure remain a challenge to global health. This lifelong disease leads to a buildup of permanent heart damage, making early detection and frequent monitoring crucial for effective treatment. N-terminal proBNP (NT-proBNP) is an important biomarker for monitoring the disease state, but current commercial and research NT-proBNP assays require phlebotomy and bulky equipment or do not satisfy clinical requirements such as sensitivity and detection thresholds. Here, we report a point-of-care (POC) compatible microfluidic digital immunoassay that can quantify the NT-proBNP concentration in a small volume of whole blood. Our automated microfluidic device takes whole blood samples mixed with biotinylated detection antibodies and passes through a plasma filter to react with a capture antibody-functionalized sensor surface. Streptavidin-coated gold nanoparticles (GNPs) are then released to mark the surface-bound single NT-proBNP immunocomplexes and recorded with bright-field microscopy. NT-proBNP concentrations in the sample are quantified via a hybrid digital/analog calibration curve. Digital counts of bound GNPs are used as readout signal at low concentrations for high sensitivity detection, and GNP pixel occupancies are used at high concentrations for extended dynamic range. With this approach, we detected NT-proBNP in the range of 8.24-10 000 pg/mL from 7 μL of whole blood in 10 min, with a limit of detection of 0.94 pg/mL. Finally, the method was validated with 15 clinical serum samples, showing excellent linear correlation (r = 0.998) with Roche's Elecsys proBNP II assay. This evidence indicates that this method holds promise for decentralized monitoring of heart failure.

A rapid method to assess the in vivo multi-functionality of adoptively transferred engineered TCR T cells

Abstract Introduction The clinical efficacy of chimeric antigen and T cell receptor (TCR) T cell immunotherapies is attributed to their ability to proliferate and persist in vivo. Since the interaction of the engineered T cells with the targeted tumour or its environment might suppress their function, their functionality should be characterized not only before but also after adoptive transfer. Materials and methods We sought to achieve this by adapting a recently developed Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid whole blood T cell assay to stimulate engineered TCR T cells in small volumes of whole blood (<1 ml) without in vitro cellular purification. As a proof-of-concept, we used this method to longitudinally study two patients with primary Hepatitis B Virus (HBV)-related hepatocellular carcinoma who received multiple dose-escalating infusions of transiently functional mRNA-engineered HBV-TCR T cells. Results We demonstrated that a simple pulsing of whole blood with a peptide corresponding to the epitope recognized by the specific HBV-TCR elicited Th1 cytokine secretion in both patients only after HBV-TCR T cell treatment and not before. The amount of cytokines secreted also showed an infusion-dose-dependent association. Discussions These findings support the utility of the whole blood cytokine release assay in monitoring the in vivo function and quantity of engineered T cell products following adoptive transfer.

Development of simple, rapid, and sensitive methods for detection of hepatitis C virus RNA from whole blood using reverse transcription loop-mediated isothermal amplification.

Hepatitis C virus (HCV) infection is an underdiagnosed global health problem. Diagnosis of current HCV infections typically requires testing for HCV RNA using high-complexity laboratory tests. Methods for the detection of HCV RNA that are simple, inexpensive, rapid, and compatible with use outside of a laboratory setting are very important in order to improve access to hepatitis C diagnostic testing and facilitate accelerated linkage to care. We developed and evaluated three simple workflows for extracting HCV RNA from small volumes of whole blood for use in a sensitive, pan-genotypic RT-LAMP assay. The water workflow uses osmotic stress to release HCV RNA and has a limit of detection of 4.3 log10(IU/mL) (95% CI 4.0-4.9). The heat workflow uses a heating step to release HCV RNA and has a limit of detection of 4.2 log10(IU/mL) (95% CI 3.8-5.1). The bead workflow, which uses chemical lysis of the sample and a streamlined paramagnetic solid phase reversible immobilization bead procedure for nucleic acid purification, has a limit of detection of 2.8 log10(IU/mL) (95% CI 2.5-3.4). When used to test whole blood spiked with HCV RNA-positive plasma samples in which most HCV levels were below 5.0 log10(IU/mL), the water, heat, and bead workflows detected HCV RNA in 69%, 75%, and 94% of samples, respectively. These workflows are compatible with visual lateral flow dipsticks, and each takes less than 60 min from sample to result. Each workflow can be performed with minimal and inexpensive equipment. With further procedural simplifications, these workflows may form the basis of assays for the point-of-care diagnosis of HCV infections.

P204 Biomechanical Phenotype of Circulating Neutrophils Is Altered in ANCA Associated Vasculitis

Abstract Background/Aims Real Time-Deformability Cytometry (RT-DC) is a novel technique able to identify morpho-rheological characteristics of individual cells such as size, deformability, and elasticity using only 50µl of whole blood. Cells in suspension flow through a microfluidic channel while hydrodynamic force is applied, leading to reversible deformation of individual cells from shear stress and pressure gradients. Cell brightness and area can be used to identify individual cell types. The morpho-rheological characteristics of immune cells in ANCA associated vasculitis (AAV) are unknown. Methods Whole blood from healthy controls (HC), patients with active AAV, or patients with AAV in remission was analysed using RT-DC. The diagnosis of AAV was based upon positive ANCA testing, with either (i) pauci-immune glomerulonephritis, or (ii) typical clinical features of extra-renal AAV. Patients with active disease may have received steroids prior to sampling but those who received other immunosuppression or cytotoxics were excluded. Remission was defined as BVAS of 0 with prednisolone dose ≤7.5mg/day. Blood was collected into K2 EDTA and diluted 1:20 in 1xPBS/0.6% methylcellulose. Cell suspensions were flowed across a Flic20 polydimethylsiloxane microfluidic chip, containing reservoirs connected by a measurement channel with a 20x20 μm2 cross-section. RT-DC measurements were collected at a flow rate of 0.12μL/s using a high-speed CMOS camera to capture images at a rate of 2000 frames/second. ShapeOut software was used to calculate cell size, deformation, and elasticity. Results There was no difference in neutrophil size between patients with active AAV (n = 15), patients with AAV in remission (n = 31), and HC (n = 15). Neutrophils from patients with active AAV were significantly stiffer than patients in remission or HC, displaying decreased deformation (median 0.084, 0.085, and 0.078 au respectively, p = 0.0068) and increased elasticity (median 0.973, 0.968 and 1.006 au respectively, p = 0.0196). In patients with active AAV, there was strong inverse correlation between neutrophil deformation and disease activity measured by BVAS score (r=-0.573, p = 0.032). Neutrophils isolated from healthy donors exhibited a trend towards decreased deformability when primed with TNF and stimulated with MPO-ANCA IgG compared to unstimulated or cells treated with healthy donor IgG (median 0.086, 0.085, and 0.083 for unstimulated, control IgG, and MPO-ANCA IgG respectively, ns). Conclusion Neutrophils from patients display distinct physical properties in active AAV which correlate with disease activity. Similar results are seen when neutrophils are stimulated in vitro with MPO-ANCA IgG. This phenotype of increased cell stiffness may lead to increased neutrophil retention in pulmonary and renal microvasculature, thus increasing the potential for neutrophil-endothelial cell interactions and microvascular damage. Morphorheological parameters can be rapidly measured using a small volume of whole blood; thus, RT-DC may be a useful technique to aid identification of disease activity in AAV and to guide treatment. Disclosure N. Pisacano: None. S.P. McAdoo: None. J. Guck: None. C.D. Pusey: None. E.R. Chilvers: None. A.C. Cowburn: None. K.M. Lodge: None. M.F. Prendecki: None.

Detekcija hemolize za merenje etanola u svim uzorcima krvi pre centrifugiranja - HemCheck uređaj

Background: As previously reported, the measurement of ethanol can also be affected by interference from hemolysis. This is a matter of concern since ethanol is widely regarded as the most commonly abused substance globally. When sample re-collection is ordered to eliminate hemolysis effects for ethanol testing, this can have unfavourable consequences for these patients. Rapid detection of hemolysed specimens would alleviate some issues associated with forensic samples. This study aimed to assess the qualitative analytical performance of a novel point-of-care testing device per the guidelines specified in CLSI-EP-12A document. HemCheck™ is a novel POCT device that qualitatively detects free-hemoglobin levels on the specimen shortly after drawing the sample. Methods: The system consists of two components. One is a cartridge with a needle that is used to transfer a small volume of whole blood from a vacuum tube to vertical and lateral flow filtration. The second component is the reader. The consumable cartridges are designed to be inserted into the reader without requiring the syringe or blood collection tube removal. A red indicator led illuminates, indicating that the sample has been hemolysed. To assess the imprecision of the method, we determined the C5-C95 interval and C50, using the Roche Cobas clinical chemistry analyser as the comparator. For this study, we utilised residual samples. Results: Our C50 concentrations were 45 mg/dL, the C5-C95 30 mg/dL and 60 mg/dL, respectively. Two methods reveal an overall agreement of 89.2%. The diagnostic sensitivity and specificity of the study showed a positive agreement of 95.7% and a negative agreement of 80.0%. The calculated Cohen's Kappa value was 77.3%. Conclusion: According to current literature, a bias in ethanol levels can be noticed even with small free hemoglobin concentrations. When it came to forensic samples, this bias was crucial. Our study confirmed that the HemCheck device has acceptable analytical performance, as outlined in the CLSI-EP-12A document. Although the possible beneficial impacts of the innovative POCT hemolysis detection device on the preanalytical phase are proposed, we have not studied them in this study.

Automated Microfluidic System with Active Mixing Enables Rapid Analysis of Biomarkers in 5 μL of Whole Blood.

We developed a microfluidic device for the rapid analysis of biomarkers in small volumes of whole blood. This device includes an onboard plasma separation module connected to a downstream bioanalysis module in which plasma mixes with reagents and the results of a colorimetric assay are recorded. Actuation of onboard microvalves within a bioanalysis module creates active mixing conditions that allowed us to achieve solution homogeneity within 5 min. To demonstrate utility, we carried out glucose detection in our device. With 5 μL of whole blood as an input, our microfluidic device enabled a time-to-answer of 10 min with a limit of detection of 0.21 ± 0.04 mM for glucose. This device has immediate applications for rapid and sensitive monitoring of hypoglycemia at the point of care (POC). Furthermore, our automated microfluidic device represents a platform technology that may be used to detect other biomarkers in whole blood.

NSeP: immune and metabolic biomarkers for early detection of neonatal sepsis—protocol for a prospective multicohort study

IntroductionDiagnosing neonatal sepsis is heavily dependent on clinical phenotyping as culture-positive body fluid has poor sensitivity, and existing blood biomarkers have poor specificity.A combination of machine learning, statistical and deep...

Point of care whole blood microfluidics for detecting and managing thrombotic and bleeding risks.

Point-of-care diagnostics of platelet and coagulation function present demanding challenges. Current clinical diagnostics often use centrifuged plasmas or platelets and frozen plasma standards, recombinant protein standards, or even venoms. Almost all commercialized tests of blood do not recreate the in vivo hemodynamics where platelets accumulate to high densities and thrombin is generated from a procoagulant surface. Despite numerous drugs that target platelets, insufficient coagulation, or excess coagulation, POC blood testing is essentially limited to viscoelastic methods that provide a clotting time, clot strength, and clot lysis, while used mostly in trauma centers with specialized capabilities. Microfluidics now allows small volumes of whole blood (<1 mL) to be tested under venous or arterial shear rates with multi-color readouts to follow platelet function, thrombin generation, fibrin production, and clot stability. Injection molded chips containing pre-patterned fibrillar collagen and lipidated tissue factor can be stored dry for 6 months at 4C, thus allowing rapid blood testing on single-use disposable chips. Using only a small imaging microscope and micropump, these microfluidic devices can detect platelet inhibitors, direct oral anticoagulants (DOACs) and their reversal agents. POC microfluidics are ideal for neonatal surgical applications that involve small blood samples, rapid DOAC testing in stroke or bleeding or emergency surgery situations with patients presenting high risk cofactors for either bleeding or thrombosis.

Indications for transfusion of blood components

Indications for transfusion of blood components

Successful Manufacturing of CAR T-Cells with Small Volume Peripheral Blood from Healthy Donors Using the Clinimacs Prodigy Device

Introduction In recent years, CAR T-cell therapy has emerged as a potentially curative intent treatment for some patients with relapsed, refractory hematologic malignancies. Despite the exciting results, not all patients are able to receive CAR T-cells due to manufacturing failures. T-cells for CAR products are typically autologous and isolated from heavily pre-treated patients, which might account for some of the manufacturing failures and suboptimal clinical efficacy. T-cells collected either early into cancer diagnosis or prior to diagnosis may improve CAR T-cell expansion and limit manufacturing failure. We evaluated the feasibility of generating a CAR T-cell product manufactured from 50 ml of healthy donor blood. Methods Collaborators at Cell Vault collected 50 ml of whole blood from 3 healthy donors, isolated peripheral blood mononuclear cells (PBMCs), and cryopreserved the cells in cryovials at 5e6/vial (1.05-1.35e8 total cells). The vials were shipped to the Medical College of Wisconsin and stored frozen in liquid nitrogen until use. All PBMC vials for a given donor were thawed and pooled. Thawed PBMCs (0.93-1.17e8 cells) were loaded onto a CliniMACS Prodigy device, CD4 and CD8 T cells enriched by immunomagnetic sorting, and T cells placed in the culture chamber with IL-7, IL-15 and TransAct reagent to induce proliferation. On the second day of manufacturing, T cells were transduced with a lentiviral CAR vector encoding anti-CD19, 4-1BB and CD3z. Final CAR T-cell products for these pre-clinical studies were harvested on day 8 of manufacture. Results Starting enriched T-cell numbers from the 3 healthy donors ranged from 4.0-4.8e7 cells, the cells were 74-79% CD4/8+, and the average CD4/CD8 ratio was 1.4. On the day of CAR T harvest (day 8), total cells in the chamber had expanded to 3.6-4.6e9 cells (74-115 fold expansion), the cells were &amp;gt;99% CD3+, and the average CD4/CD8 ratio was 2.9 (Table 1). Final cell numbers were similar to what previously published CAR T manufacturing runs on the CliniMACS Prodigy (Zhu et al., Cytotherapy, 2018), that started with 1x108 enriched T-cells obtained from apheresed mononuclear cells. Cell surface CD19 CAR expression on the final cell products varied from 19.2-48.1%. While more than 50% of the starting T cells had a naïve (CD62L+ CD45RO-) phenotype, the final cell products contained greater than 80% central-memory (CD62L+ CD45RO+) T cells. Finally, the number of CD19 CAR T cells obtained from these pre-clinical manufacturing runs ranged from 7.82e8 to 2.21e9 cells. Conclusions 50 ml of cryopreserved PBMCs was adequate to manufacture clinically relevant CAR T-cell therapy doses from healthy donors not previously exposed to chemotherapy. Sufficient numbers of CAR T-cells were obtained to dose an 80 kg individual with at least 9e6 cells/kg which is greater than prescribed commercial doses of CD19 CAR T-cells. Further studies are indicated to determine if T-cells collected prior to disease modifying chemotherapies result in an improved product. These results demonstrate feasibility for generating CAR T cells from small volumes of whole blood collected at a time point before a cancer patient has been treated with multiple lines of therapy that could negatively impact starting T cell numbers and function. Disclosures Hari: GSK: Consultancy; Amgen: Consultancy; BMS: Consultancy; Takeda: Consultancy; Incyte Corporation: Consultancy; Janssen: Consultancy. Shah:TG Therapeutics: Consultancy; Celgene: Consultancy, Honoraria; Incyte: Consultancy; Kite Pharma: Consultancy, Honoraria; Cell Vault: Research Funding; Miltenyi Biotec: Honoraria, Research Funding; Lily: Consultancy, Honoraria; Verastim: Consultancy. Johnson:Miltenyi Biotec: Research Funding; Cell Vault: Research Funding.

Development and Validation of an ICP-MS Method and Its Application to Determine Multiple Trace Elements in Small Volumes of Whole Blood and Plasma.

Essential and nonessential element concentrations in human blood provide important information on the nutritional status of individuals and can assist in the screening or diagnosis of certain disorders and their association with other causative factors. A simple and sensitive method, suitable for use with small sample volumes, for quantification of multiple trace element concentrations in whole blood and plasma has been developed using inductively coupled plasma-mass spectrometry. Method validation was performed using standard reference materials of whole blood and serum using varying sample treatments with nitric acid, water and hydrogen peroxide. The method was applied to quantify the trace element concentrations in whole blood and plasma samples (0.1mL) from 50 adult blood donors in Queensland. The whole blood sample (5mL) was collected in Vacutainer tubes with K2EDTA as anticoagulant. The developed method was able to quantify, in blood and plasma samples over a wide range of concentrations, several essential elements: cobalt, copper, zinc, iron, manganese and selenium; the nutritionally probably essential elements vanadium and strontium; and nonessential elements including lead, cadmium, arsenic, caesium, barium, thallium and uranium. Significant differences (P<0.0001) were observed between whole blood and plasma concentrations for 13 elements; 5 of the measured elements, cobalt (0.49 vs. 0.36μg/L), copper (1.0 vs. 0.75mg/L), strontium (28 vs. 16μg/L), barium (1.5 vs. 0.64μg/L) and thallium (0.06 vs. 0.03μg/L), had higher mean concentrations in plasma than in blood. Whole blood concentrations of nine trace elements were significantly correlated (P<0.0001) with plasma concentrations. The distribution of the trace elements between human blood and plasma varied considerably for the different elements. These results indicate that, using a small sample volume, this assay is suitable for the evaluation of nutritional status as well as in monitoring human toxic elemental exposures.

OMIP-062: A 14-Color, 16-Antibody Panel for Immunophenotyping Human Innate Lymphoid, Myeloid and T Cells in Small Volumes of Whole Blood and Pediatric Airway Samples.

OMIP-062: A 14-Color, 16-Antibody Panel for Immunophenotyping Human Innate Lymphoid, Myeloid and T Cells in Small Volumes of Whole Blood and Pediatric Airway Samples.

Fully automated thromboelastograph TEG 6s to measure anticoagulant effects of direct oral anticoagulants in healthy male volunteers

BackgroundThe ability to assess the hemostatic effect of the direct oral anticoagulant (DOACs) may be valuable in clinical situations such as bleeding or thrombosis, before urgent surgery, or reversal of anticoagulation. We sought to assess the anticoagulant effect of DOACs with the new‐generation fully automated thrombelastograph TEG 6s using resonance‐frequency viscoelasticity measurements and disposable multichannel microfluidic cartridges. MethodsA single dose of oral dabigatran 150 mg, rivaroxaban 20 mg, or apixaban 5 mg was given to 9 healthy males. Phlebotomy was performed at 0, 1, and 3 hours after administration of DOAC. TEG parameters were measured using TEG_6s. Concentrations of DOACs were measured using chromogenic assays. The TEG parameters were correlated to the DOAC concentrations. ResultsThe reaction time (R) demonstrated the strongest response to DOAC intake. There were no correlations between other TEG parameters and DOAC concentrations. Using the direct thrombin inhibitor (DTI) channel, R was significantly correlated with dabigatran levels (r=0.94, P<0.0001). Using the anti–factor Xa (AFXa) channel, R was significantly correlated with rivaroxaban and apixaban levels (r=0.93 and r=0.83, respectively; P<0.0001 for both). R >2.5 minutes for dabigatran (DTI channel), >2.5 minutes for apixaban, and >1.8 minutes for rivaroxaban (AFXa channel) were associated with 100% sensitivity and ≥ 90% specificity to detect DOAC levels of ≥ 50 ng/mL. ConclusionWe have demonstrated that TEG_6s R has significant correlation with DOAC blood concentrations and has potential for monitoring the DOAC's effect on hemostasis with reasonable sensitivity in the small sample analyzed. This novel technology is easy to use on a small volume of whole blood without requiring a specialized laboratory. Further study is warranted to correlate R with clinical outcomes.

Simultaneous determination of cardiovascular drugs in dried blood spot by liquid chromatography-tandem mass spectrometry

A dried blood spot (DBS) sampling method was exploited to extract cardiovascular drugs using a small volume of whole blood of human and rodent. Thereafter, an analytical method using liquid chromatography with tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of 12 cardiovascular drugs. A 6 mm internal diameter disc containing 10 μL of blood was punched from a specifically designed card and analyzed by LC-MS/MS using a gradient elution method with a total run time of 16 min. For sample separation, a universal octadecyl-silica column was used with a flow rate of 0.2 mL/min. The developed method was validated in terms of linearity, accuracy, and precision, which showed satisfactory results. In addition, the matrix effects were closely investigated to confirm the extraction efficiency. Additionally, the stability was tested by storing DBSs at room temperature; the results showed that these drugs were stable for at least 30 days. Accordingly, the proposed LC-MS/MS method is capable to analyze several cardiovascular drugs in a single analysis. It can be applied to therapeutic drug monitoring in patients as well as in the in vivo settings.

High-Throughput Profiling of Circulating Antibody Signatures for Stroke Diagnosis Using Small Volumes of Whole Blood.

Accurate stroke recognition during triage can streamline care and afford patients earlier access to life-saving interventions. However, the tools currently available to clinicians for prehospital and early in-hospital identification of stroke are limited. The peripheral immune system is intricately involved in stroke pathology and thus may be targetable for the development of immunodiagnostics. In this preliminary study, we sought to determine whether the circulating antibody pool is altered early in stroke, and whether such alterations could be leveraged for diagnosis. One hundred microliters of peripheral whole blood was sampled from 19 ischemic stroke patients, 17 hemorrhagic stroke patients, and 20 stroke mimics in the acute phase of care. A custom-fabricated high-density peptide array comprising 125,000 unique probes was used to assess the binding characteristics of blood-borne antibodies, and a random forest-based approach was used to select a parsimonious set of probes with an optimal ability to discriminate between groups. The coordinate antibody binding intensities of the top 17 probes identified in our analysis displayed an ability to differentiate the total pool of stroke patients from stroke mimics with 92% sensitivity and 90% specificity, as well as detect hemorrhage with 88% sensitivity and 87% specificity, as determined using a same-set cross-validation. These preliminary findings suggest that stroke-associated alterations in the circulating antibody pool may have clinical utility for diagnosis during triage, and that such a possibility warrants further investigation.

Separation and Counting of Lymphocytes from Small Volume of Whole Blood

Separation and Counting of Lymphocytes from Small Volume of Whole Blood

Design and Utility of a Point-of-Care Microfluidic Platform to Assess Hematocrit and Blood Coagulation.

To develop a small volume whole blood analyzer capable of measuring the hematocrit and coagulation kinetics of whole blood. A co-planar microfluidic chamber designed to facilitate self-driven capillary action across an internal electrical chip was developed and used to measure the electric parameters of whole human blood that had been anticoagulated or allowed to clot. To promote blood clotting, select chip surfaces were coated with a prothrombin time (PT) reagent containing lipidated tissue factor (TF), which activates the extrinsic pathway of coagulation to promote thrombin generation and fibrin formation. Whole human blood was added to the microfluidic device, and voltage changes within the platform were measured and interpreted using basic resistor-capacitor (RC) circuit and fluid dynamics theory. Upon wetting of the sensing zone, a circuit between two co-planar electrodes within the sensing zone was closed to generate a rapid voltage drop from baseline. The voltage then rose due to sedimentation of red blood cells (RBC) in the sensing zone. For anticoagulated blood samples, the time for the voltage to return to baseline was dependent on hematocrit. In the presence of coagulation, the initiation of fibrin formation in the presence of the PT reagent prevented the return of voltage to baseline due to the reduced packing of RBCs in the sensing zone. The technology presented in this study has potential for monitoring the hematocrit and coagulation parameters of patient samples using a small volume of whole blood, suggesting it may hold clinical utility as a point-of-care test.

Recellularization of Decellularized Venous Grafts Using Peripheral Blood: A Critical Evaluation

Vascular disease is a major cause of death worldwide, and the growing need for replacement vessels is not fully met by autologous grafts or completely synthetic alternatives. Tissue engineering has emerged as a compelling strategy for the creation of blood vessels for reconstructive surgeries.One promising method to obtain a suitable vessel scaffold is decellularization of donor vascular tissue followed by recellularization with autologous cells. To prevent thrombosis of vascular grafts, a confluent and functional autologous endothelium is required, and researchers are still looking for the optimal cell source and recellularization procedure.Recellularization of a decellularized scaffold with only a small volume of whole blood was recently put forward as a feasible option. Here we show that, in contrast to the published results, this method fails to re-endothelialize decellularized veins. Only occasional nucleated cells were seen on the luminal surface of the scaffolds. Instead, we saw fibrin threads, platelets and scattered erythrocytes. Molecular remnants of the endothelial cells were still attached to the scaffold, which explains in part why earlier results were misinterpreted.Decellularized vascular tissues may still be the best scaffolds available for vascular tissue engineering. However, for the establishment of an adequate autologous endothelial lining, methods other than exposure to autologous whole blood need to be developed.

Toward Flow Cytometry Based Platelet Function Diagnostics.

The laboratory diagnostics of (inherited) platelet function disorders mainly comprises aggregation and secretion assays, which may be suitable for diagnosing some specific severe platelet function disorders, but are not reliable enough for diagnosing mild platelet function disorders or disorders associated with low platelet count. Flow cytometric assessment of platelet reactivity will expectedly provide additional value during the diagnostic work-up of platelet function disorders because it only requires a small volume of whole blood and allows the measurement of platelet function in thrombocytopenic samples. Flow cytometry has frequently been used to evaluate platelet function in the research setting, and therefore, these assays will require clinical validation before they can be used as routine diagnostic tools. The main challenge in the validation of innovative platelet function diagnostic tests is the lack of a gold standard test for mild platelet function disorders. This review aims to address the many applications of flow cytometry in the current diagnostic work-up of platelet function testing and to discuss the challenges in introducing new tools for diagnosing platelet function disorders.

Coagulation measurement from whole blood using vibrating optical fiber in a disposable cartridge.

In clinics, blood coagulation time measurements are performed using mechanical measurements with blood plasma. Such measurements are challenging to do in a lab-on-a-chip (LoC) system using a small volume of whole blood. Existing LoC systems use indirect measurement principles employing optical or electrochemical methods. We developed an LoC system using mechanical measurements with a small volume of whole blood without requiring sample preparation. The measurement is performed in a microfluidic channel where two fibers are placed inline with a small gap in between. The first fiber operates near its mechanical resonance using remote magnetic actuation and immersed in the sample. The second fiber is a pick-up fiber acting as an optical sensor. The microfluidic channel is engineered innovatively such that the blood does not block the gap between the vibrating fiber and the pick-up fiber, resulting in high signal-to-noise ratio optical output. The control plasma test results matched well with the plasma manufacturer's datasheet. Activated-partial-thromboplastin-time tests were successfully performed also with human whole blood samples, and the method is proven to be effective. Simplicity of the cartridge design and cost of readily available materials enable a low-cost point-of-care device for blood coagulation measurements.