فإن الكتاب أود أن أشكر جو أوين في الصك الطبية الحيوية وصناعة الآلات لجهوده الدؤوبة في تصنيع وتجميع أجزاء الغرفة ، وتدفق ماودسلي مات من ايكا مايكروسيستمز للمساعدة في تقنيات الخلايا الصورة من خلال غرف التدفق. نحن مدينون لكيفن كولينز من خدمات الإرواء ديوك ، والدكتور ستيف والاس في قسم الهندسة الطبية الحيوية للحصول على اقتراحات مفيدة حول تصميم الدوائر التدفق. نود أيضا أن نشكر المؤسسة الوطنية للعلوم بحوث زمالة دراسات عليا لدعم برنامج الكسندرا Jantzen والمعاهد الوطنية للصحة في لدعمهم من خلال المنح &quot;بطانة EPC ذاتي لتحسين الدورة الدموية للتوافق مع الحياة مساعدة الأجهزة&quot; RC1HL099863 - 01.

<ol>
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وترعى الإنتاج وحرية الوصول من هذه المادة عن طريق الفيديو من قبل شركة الصك كول - Parmer

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> منتجات / الكواشف </td><td> شركة </td><td> المنتج # </td></tr><tr><td> الحقنة 10 مل </td><td> شركة كول Parmer الصك </td><td> 07940-12 </td></tr><tr><td> 1 الطريق Stopcoks </td><td> شركة كول Parmer الصك </td><td> 30600-00 </td></tr><tr><td> الحقنة 30 مل </td><td> دينار بحريني الطبية </td><td> 309650 </td></tr><tr><td> 4 طريق الصمامات </td><td> شركة كول Parmer الصك </td><td> 30600-04 </td></tr><tr><td> سبائك الالومنيوم </td><td> N / A </td><td> 6061 </td></tr><tr><td> خلية ثقافة صحون (4 - جيدا ، مستطيل) </td><td> الحرارية العلمية ؛ نونك </td><td> 267061 </td></tr><tr><td> المقتفي الخلية البرتقالية </td><td> Invitrogen </td><td> C34551 </td></tr><tr><td> DMSO </td><td> البحوث العضوية </td><td> 2162D </td></tr><tr><td> DPBS (-/-)</td><td> Invitrogen </td><td> 14190-144 </td></tr><tr><td> EGM - 2 Singlequots </td><td> Lonza </td><td> CC - 4176 </td></tr><tr><td> Luer محول الإناث </td><td> شركة كول Parmer الصك </td><td> سي 45500-04 </td></tr><tr><td> فبرونيكتين </td><td> سيغما </td><td> F0895 - 2MG </td></tr><tr><td> زجاجة (250ml) مع كاب </td><td> شركة كول Parmer الصك </td><td> 34594-24 </td></tr><tr><td> أنابيب الصلب </td><td> شركة كول Parmer الصك </td><td> 06508-16 </td></tr><tr><td> HBSS </td><td> سيغما </td><td> H8264 - 500ML </td></tr><tr><td> Histopaque </td><td> سيغما </td><td> H8889 - 500ML </td></tr><tr><td> هويشت الحل اللطخة </td><td> سيغما </td><td> H6024 </td></tr><tr><td> Hyclone FBS </td><td> الحرارية العلمية </td><td> SH30071.01 </td></tr><tr><td> L - الجلوتامين </td><td> Lonza </td><td> 17 - 605E </td></tr><tr><td> Luer محول الذكور </td><td> شركة كول Parmer الصك </td><td> EW - 45505-04 </td></tr><tr><td> MCDB - 131 ، متوسطة 1X </td><td> Cellgro </td><td> 15-100 - CV </td></tr><tr><td> تركيبات والبولي بروبيلين الشائكة </td><td> شركة كول Parmer الصك </td><td> 06365-90 </td></tr><tr><td> O - خواتم </td><td> N / A </td><td> AS568A </td></tr><tr><td> نبض يستمتع </td><td> شركة كول Parmer الصك </td><td> 07596-20 </td></tr><tr><td> محرك المضخة (Masterflex L / S محرك الاقتصاد متغيرة السرعة) </td><td> شركة كول Parmer الصك </td><td> 7524-40 </td></tr><tr><td> رئيس المضخة (مضخة Masterflex تحميل سهلة الرئيسي) </td><td> شركة كول Parmer الصك </td><td> 07518-60 </td></tr><tr><td> الشريحة </td><td> شركة كول Parmer الصك </td><td> 48500-00 </td></tr><tr><td> أنابيب لينة </td><td> شركة كول Parmer الصك </td><td> 96400-16 </td> &lt;/ TR&gt; <tr><td> حقنة التصفية </td><td> شركة كول Parmer الصك </td><td> 02915-12 </td></tr><tr><td> Sytox أورانج الأحماض النووية اللطخة </td><td> Invitrogen </td><td> S - 11368 </td></tr><tr><td> التربسين EDTA </td><td> Lonza </td><td> CC - 5012 </td></tr><tr><td> تحييد الحل التربسين </td><td> Lonza </td><td> CC - 5002 </td></tr></tbody></table>

parallel-plate flow chamber and continuous flow circuit to evaluate endothelial progenitor cells under laminar flow shear stress

الهدف العام لهذا الأسلوب هو لوصف تقنية لموضوع الخلايا تمسكا ظروف التدفق الصفحي وتقييم استجابتها للالقص السوائل القابلة للقياس الكمي كذلك تشدد 1. لدينا تصميم غرفة تدفق وتدفق الدائرة (الشكل 1) يحتوي على منطقة العرض الشفافة التي يمكن اختبار خلية التصاق والتصوير من مورفولوجية الخلية مباشرة قبل تدفق (الشكل رقم 11A ، B) ، في نقاط زمنية مختلفة خلال التدفق (الشكل رقم 11C) وبعد تدفق (الشكل 11D). وتتجلى هذه التجارب مع دم الحبل السري الإنسان المستمدة من الخلايا الاصلية البطانية (EPCs) والخنازير EPCs 2،3. هذا الأسلوب ينطبق أيضا على غيرها من أنواع الخلايا الملتصقة ، مثل خلايا العضلات الملساء (SMCs) أو الليفية. يتم تعقيمها بسهولة الغرفة وجميع أجزاء الدائرة مع التعقيم بالبخار. على النقيض من غيرهاالغرف ، يمكن استرداد مثل غرف ميكروفلويديك ، فإن أعدادا كبيرة من الخلايا (&gt; 1000000 اعتمادا على حجم الخلية) بعد التجربة تدفق تحت ظروف معقمة للثقافة الخلية أو تجارب أخرى ، مثل الحمض النووي الريبي أو استخراج ، أو المناعية (الشكل 11E) ، أو المجهر الإلكتروني 5. يمكن تعديل إجهاد القص من خلال تغيير معدل تدفق سائل الإرواء ، واللزوجة السوائل ، أو ارتفاع وعرض القناة. يمكن لهذا الأخير خفض حجم السائل أو احتياجات الخلية مع ضمان الحفاظ على تدفق ذات بعد واحد. ليس من الضروري لقياس ارتفاع الغرفة بين التجارب ، منذ ذروة الغرفة لا تعتمد على استخدام حشوات ، مما يزيد كثيرا من سهولة تجارب متعددة. وعلاوة على ذلك ، وتصميم الدوائر تمكن بسهولة جمع عينات سائل الإرواء و / أو التحليل الكمي للالأيضات يفرز من قبل خلايا السائل تحت التعرض للإجهاد القص ، مثل أكسيد النيتريك (الشكل 12) 6 </suع&gt;.

Watch this Scientific Journal Video about Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress at JoVE.com

Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress

نحن تصف طريقة لخلايا ملتصقة تخضع لتدفق الصفحي إجهاد القص في دائرة التدفق المستمر العقيمة. التصاق الخلايا &quot;، ويمكن من خلال دراسة مورفولوجية غرفة شفافة ، والعينات التي تم الحصول عليها من الدوائر لتحليل المستقلب والخلايا التي تحصد بعد التعرض لتجارب القص في المستقبل أو الثقافة.

موازية لوحة الدائرة التدفق المستمر وحلبة لتقييم تدفق الخلايا الاصلية تحت تدفق رقائقي غشائي إجهاد القص

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well ...

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43.2K Views.  Duke University Medical Center. نحن تصف طريقة لخلايا ملتصقة تخضع لتدفق الصفحي إجهاد القص في دائرة التدفق المستمر العقيمة. التصاق الخلايا "، ويمكن من خلال دراسة مورفولوجية غرفة شفافة ، والعينات التي تم الحصول عليها من الدوائر لتحليل المستقلب والخلايا التي تحصد بعد التعرض لتجارب القص في المس...

Video: Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress

Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow

Microfluidic devices have advanced cell studies by providing a dynamic fluidic environment on the scale of the cell for studying, manipulating, sorting and counting cells. However, manipulating the cell within the fluidic domain remains a challenge and requires complicated fabrication protocols for forming valves and electrodes, or demands specialty equipment like optical tweezers. Here, we demonstrate that conventional printed circuit boards (PCB) can be used for the non-contact manipulation of cells by employing dielectrophoresis (DEP) for bead and cell manipulation in laminar flow fields for bioactuation, and for cell and bead separation in multichannel microfluidic devices. First, we present the protocol for assembling the DEP electrodes and microfluidic devices, and preparing the cells for DEP. Then, we characterize the DEP operation with polystyrene beads. Lastly, we show representative results of bead and cell separation in a multichannel microfluidic device. In summary, DEP is an effective method for manipulating particles (beads or cells) within microfluidic devices.

Dielectrophoresis (DEP) is an effective method to manipulate cells. Printed circuit boards (PCB) can provide inexpensive, reusable and effective electrodes for contact-free cell manipulation within microfluidic devices. By combining PDMS-based microfluidic channels with coverslips on PCBs, we demonstrate bead and cell manipulation and separation within multichannel microfluidic devices.

الخرز وفصل الخلايا في أجهزة ميكروفلويديك متعدد القنوات باستخدام Dielectrophoresis وتدفق رقائقي

Microfluidic devices have advanced cell studies by providing a dynamic fluidic environment on the scale of the cell for studying, manipulating, sorting ...

A Novel Three-dimensional Flow Chamber Device to Study Chemokine-directed Extravasation of Cells Circulating under Physiological Flow Conditions

Extravasation of circulating cells from the bloodstream plays a central role in many physiological and pathophysiological processes, including stem cell homing and tumor metastasis. The three-dimensional flow chamber device (hereafter the 3D device) is a novel in vitro technology that recreates physiological shear stress and allows each step of the cell extravasation cascade to be quantified. The 3D device consists of an upper compartment in which the cells of interest circulate under shear stress, and a lower compartment of static wells that contain the chemoattractants of interest. The two compartments are separated by porous inserts coated with a monolayer of endothelial cells (EC). An optional second insert with microenvironmental cells of interest can be placed immediately beneath the EC layer. A gas exchange unit allows the optimal CO2 tension to be maintained and provides an access point to add or withdraw cells or compounds during the experiment. The test cells circulate in the upper compartment at the desired shear stress (flow rate) controlled by a peristaltic pump. At the end of the experiment, the circulating and migrated cells are collected for further analyses. The 3D device can be used to examine cell rolling on and adhesion to EC under shear stress, transmigration in response to chemokine gradients, resistance to shear stress, cluster formation, and cell survival. In addition, the optional second insert allows the effects of crosstalk between EC and microenvironmental cells to be examined. The translational applications of the 3D device include testing of drug candidates that target cell migration and predicting the in vivo behavior of cells after intravenous injection. Thus, the novel 3D device is a versatile and inexpensive tool to study the molecular mechanisms that mediate cellular extravasation.

The three-dimensional flow chamber device is a novel in vitro technology for the quantitative and step-wise evaluation of the extravasation cascade of cells circulating under conditions of physiological shear stress. The device therefore fills a critical need for basic, preclinical, and clinical studies of cell migration.

رواية ثلاثي الأبعاد التدفق جهاز الدائرة لدراسة Chemokine الموجه التسرب من خلايا اعارة تحت ظروف تدفق الفسيولوجي

Extravasation of circulating cells from the bloodstream plays a central role in many physiological and pathophysiological processes, including stem cell ...

The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell phenotype after printing, poor organization and distribution of desired cells, and the inability to deliver drugs and/or nutrients to targeted areas in the array. Our 3D microfluidic printing technology is uniquely capable of sealing and printing arrays of cells onto submerged surfaces in an automated and multiplexed manner. The design of the microfluidic cell array (MFCA) 3D fluidics enables the printhead tip to be lowered into a liquid-filled well or dish and compressed against a surface to form a seal. The soft silicone tip of the printhead behaves like a gasket and is able to form a reversible seal by applying pressure or backing away. Other cells printing technologies such as pin or ink-jet printers are unable to print in submerged applications. Submerged surface printing is essential to maintain phenotypes of cells and to monitor these cells on a surface without disturbing the material surface characteristics. By printing onto submerged surfaces, cell microarrays are produced that allow for drug screening and cytotoxicity assessment in a multitude of areas including cancer, diabetes, inflammation, infections, and cardiovascular disease.

This 3D microfluidic printing technology prints arrays of cells onto submerged surfaces. We describe how arrays of cells are delivered microfluidically in 3D flow cells onto submerged surfaces. By printing onto submerged surfaces, cell microarrays were produced that allow for drug screening and cytotoxicity assessment in a multitude of areas.

الطباعة المغمورة من خلايا على سطح معدلة باستخدام التدفق المستمر Microspotter

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell ...

Assessing Leukocyte-endothelial Interactions Under Flow Conditions in an Ex Vivo Autoperfused Microflow Chamber Assay

Leukocyte-endothelial interactions are early and critical events in acute and chronic inflammation and can, when dysregulated, mediate tissue injury leading to permanent pathological damage. Existing conventional assays allow the analysis of leukocyte adhesion molecules only after the extraction of leukocytes from the blood. This requires the blood to undergo several steps before peripheral blood leukocytes (PBLs) can be ready for analysis, which in turn can stimulate PBLs influencing the research findings. The autoperfused micro flow chamber assay, however, allows scientists to study early leukocytes functional dysregulation using the systemic flow of a live mouse while having the freedom of manipulating a coated chamber. Through a disease model, the functional expression of leukocyte adhesion molecules can be assessed and quantified in a micro-glass chamber coated with immobilized endothelial adhesion molecules ex vivo. In this model, the blood flows between the right common carotid artery and left external jugular vein of a live mouse under anesthesia, allowing the interaction of native PBLs in the chamber. Real-time experimental analysis is achieved with the assistance of an intravital microscope as well as a Harvard Apparatus pressure device. The application of a flow regulator at the input point of the glass chamber allows comparable physiological flow conditions amongst the experiments. Leukocyte rolling velocity is the main outcome and is measured using the National Institutes of Health open-access software ImageJ. In summary, the autoperfused micro flow chamber assay provides an optimal physiological environment to study leukocytes endothelial interaction and allows researchers to draw accurate conclusions when studying inflammation.

Assessing Leukocyte-endothelial Interactions Under Flow Conditions in an Ex Vivo Autoperfused Microflow Chamber Assay

Here, we present a protocol that allows the investigator to assess leukocyte recruitment dynamics ex vivo by connecting a chamber coated with endothelial-derived adhesion molecules to the circulatory system of a mouse. This method offers significant advantages since it allows for leukocyte assessment under relative biological conditions.

تقييم التفاعلات الكريات البيض البطانية تحت ظروف التدفق في<em&gt; فيفو السابقين</em&gt; الفحص Autoperfused غرفة Microflow

Leukocyte-endothelial interactions are early and critical events in acute and chronic inflammation and can, when dysregulated, mediate tissue injury ...

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is restricted to platelet deposition only. The intricate relationship between Ca2+-dependent coagulation and platelet function requires careful and controlled recalcification of blood prior to analysis. Our setup uses a Y-shaped mixing channel, which supplies concentrated Ca2+/Mg2+ buffer to flowing blood just prior to perfusion, enabling rapid recalcification without sample stasis. A ten-fold difference in flow velocity between both reservoirs minimizes dilution. The recalcified blood is then perfused in a collagen-coated analysis chamber, and differential labeling permits real-time imaging of both platelet and fibrin deposition using fluorescence video microscopy. The system uses only commercially available tools, increasing the chances of standardization. Reconstitution of thrombocytopenic blood with platelets from banked concentrates furthermore models platelet transfusion, proving its use in this research domain. Exemplary data demonstrated that coagulation onset and fibrin deposition were linearly dependent on the platelet concentration, confirming the relationship between primary and secondary hemostasis in our model. In a timeframe of 16 perfusion min, contact activation did not take place, despite recalcification to normal Ca2+ and Mg2+ levels. When coagulation factor XIIa was inhibited by corn trypsin inhibitor, this time frame was even longer, indicating a considerable dynamic range in which the changes in the procoagulant nature of the platelets can be assessed. Co-immobilization of tissue factor with collagen significantly reduced the time to onset of coagulation, but not its rate. The option to study the tissue factor and/or the contact pathway increases the versatility and utility of the assay.

This paper describes an experimental model of hemostasis that simultaneously measures platelet function and coagulation. Platelet and fibrin fluorescence is measured in real-time, and platelet adhesion rate, coagulation rate, and onset of coagulation are determined. The model is used to determine platelet procoagulant properties under flow in concentrates for transfusion.

للدائرة نموذج ميكروفلويديك تدفق لصفائح الدم نقل والإرقاء يقيس ترسب الصفائح الدموية والليفين تشكيل في الوقت الحقيقي

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is ...

Isolation of Primary Murine Retinal Ganglion Cells (RGCs) by Flow Cytometry

Neurodegenerative diseases often have a devastating impact on those affected. Retinal ganglion cell (RGC) loss is implicated in an array of diseases, including diabetic retinopathy and glaucoma, in addition to normal aging. Despite their importance, RGCs have been extremely difficult to study until now due in part to the fact that they comprise only a small percentage of the wide variety of cells in the retina. In addition, current isolation methods use intracellular markers to identify RGCs, which produce non-viable cells. These techniques also involve lengthy isolation protocols, so there is a lack of practical, standardized, and dependable methods to obtain and isolate RGCs. This work describes an efficient, comprehensive, and reliable method to isolate primary RGCs from mice retinae using a protocol based on both positive and negative selection criteria. The presented methods allow for the future study of RGCs, with the goal of better understanding the major decline in visual acuity that results from the loss of functional RGCs in neurodegenerative diseases.

Isolation of Primary Murine Retinal Ganglion Cells RGCs by Flow Cytometry

Millions of people suffer from retinal degenerative diseases that result in irreversible blindness. A common element of many of these diseases is the loss of retinal ganglion cells (RGCs). This detailed protocol describes the isolation of primary murine RGCs by positive and negative selection with flow cytometry.

عزل الخلايا العقدة الشبكية الفئران الأولية (رغس) عن طريق التدفق الخلوي

Neurodegenerative diseases often have a devastating impact on those affected. Retinal ganglion cell (RGC) loss is implicated in an array of diseases, ...

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate flow chambers. Endothelial cells form the inner cellular lining of blood vessels and are chronically exposed to the frictional force of blood flow called shear stress. Under physiological conditions, endothelial cells function in the presence of various shear stress conditions. Thus, the application of shear stress conditions in in vitro models can provide greater insight into endothelial responses in vivo. The parallel-plate flow chamber previously published by Lane et al.9 is adapted to study endothelial gene regulation in the presence and absence of steady (non-pulsatile) laminar flow. Key adaptations in the set-up for laminar flow as presented here include a large, dedicated environment to house concurrent flow circuits, the monitoring of flow rates in real-time, and the inclusion of an exogenous reference RNA for the normalization of quantitative real-time PCR data. To assess multiple treatments/conditions with the application of shear stress, multiple flow circuits and pumps are used simultaneously within the same heated and humidified incubator. The flow rate of each flow circuit is measured continuously in real-time to standardize shear stress conditions throughout the experiments. Because these experiments have multiple conditions, we also use an exogenous reference RNA that is spiked-in at the time of RNA extraction for the normalization of RNA extraction and first-strand cDNA synthesis efficiencies. These steps minimize the variability between samples. This strategy is employed in our pipeline for the gene expression analysis with shear stress experiments using the parallel-plate flow chamber, but parts of this strategy, such as the exogenous reference RNA spike-in, can easily and cost-effectively be used for other applications.

Here, a workflow for the culture and gene expression analysis of endothelial cells under fluid shear stress is presented. Included is a physical arrangement for simultaneously housing and monitoring multiple flow chambers in a controlled environment and the use of an exogenous reference RNA for quantitative PCR.

تحليل التعبير الجيني غشائي الخلايا المعرضة للإجهاد باستخدام عدة تدفق مواز-لوحة الدوائر للقص

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate ...

Characterizing Single-Molecule Conformational Changes Under Shear Flow with Fluorescence Microscopy

Single-molecule behavior under mechanical perturbation has been characterized widely to understand many biological processes. However, methods such as atomic force microscopy have limited temporal resolution, while F&#246;rster resonance energy transfer (FRET) only allow conformations to be inferred. Fluorescence microscopy, on the other hand, allows real-time in situ visualization of single molecules in various flow conditions. Our protocol describes the steps to capture conformational changes of single biomolecules under different shear flow environments using fluorescence microscopy. The shear flow is created inside microfluidic channels and controlled by a syringe pump. As demonstrations of the method, von Willebrand factor (VWF) and lambda DNA are labeled with biotin and fluorophore and then immobilized on the channel surface. Their conformations are continuously monitored under variable shear flow using total internal reflection (TIRF) and confocal fluorescence microscopy. The reversible unraveling dynamics of VWF are useful for understanding how its function is regulated in human blood, while the conformation of lambda DNA offers insights into the biophysics of macromolecules. The protocol can also be widely applied to study the behavior of polymers, especially biopolymers, in varying flow conditions and to investigate the rheology of complex fluids.

We present a protocol for immobilizing single macromolecules in microfluidic devices and quantifying changes in their conformations under shear flow. This protocol is useful for characterizing the biomechanical and functional properties of biomolecules such as proteins and DNA in a flow environment.

توصيف التغيرات التشكيلية أحادية الجزيء تحت تدفق القص مع المجهر الفلوري

Single-molecule behavior under mechanical perturbation has been characterized widely to understand many biological processes. However, methods such as ...

Asymmetrical Flow Field-Flow Fractionation for Sizing of Gold Nanoparticles in Suspension

Particle size is arguably the most important physico-chemical parameter associated with the notion of a nanoparticle. Precise knowledge of the size and size distribution of nanoparticles is of utmost importance for various applications. The size range is also important, as it defines the most &#8220;active&#8221; component of a nanoparticle dose.
Asymmetrical Flow Field-Flow Fractionation (AF4) is a powerful technique for sizing of particles in suspension in the size range of approximately 1&#8211;1000 nm. There are several ways to derive size information from an AF4 experiment. Besides coupling AF4 online with size-sensitive detectors based on the principles of Multi-Angle Light Scattering or Dynamic Light Scattering, there is also the possibility to correlate the size of a sample with its retention time using a well-established theoretical approach (FFF theory) or by comparing it with the retention times of well-defined particle size standards (external size calibration).
We here describe the development and in-house validation of a standard operating procedure (SOP) for sizing of an unknown gold nanoparticle sample by AF4 coupled with UV-vis detection using external size calibration with gold nanoparticle standards in the size range of 20&#8211;100 nm. This procedure provides a detailed description of the developed workflow including sample preparation, AF4 instrument setup and qualification, AF4 method development and fractionation of the unknown gold nanoparticle sample, as well as the correlation of the obtained results with the established external size calibration. The SOP described here was eventually successfully validated in the frame of an interlaboratory comparison study highlighting the excellent robustness and reliability of AF4 for sizing of nanoparticulate samples in suspension.

This protocol describes the use of Asymmetrical Flow Field-Flow Fractionation coupled with UV-vis detection for the determination of the size of an unknown gold nanoparticle sample.

تجزئة تدفق غير متماثل لتحجيم الجسيمات النانوية الذهبية في التعليق

Particle size is arguably the most important physico-chemical parameter associated with the notion of a nanoparticle. Precise knowledge of the size and ...

Blood Flow Imaging with Ultrafast Doppler

The pulsed-Doppler effect is the main technique used in clinical echography to assess blood flow. Applied with conventional focused ultrasound Doppler modes, it has several limits. Firstly, a finely tuned signal filtering operation is needed to distinguish blood flows from surrounding moving tissues. Secondly, the operator must choose between localizing the blood flows or quantifying them. In the last two decades, ultrasound imaging has undergone a paradigm shift with the emergence of ultrafast ultrasound using unfocused waves. In addition to a hundredfold increase in framerate (up to 10000 Hz), this new technique also breaks the conventional quantification/localization trade-off, offering a complete blood flow mapping of the field of view and a simultaneous access to fine velocities measurements at the single-pixel level (down to 50 &#181;m). This data continuity in both spatial and temporal dimensions strongly improves the tissue/blood filtering process, which results in an increase sensitivity to small blood flow velocities (down to 1 mm/s). In this method paper, we aim to introduce the concept of ultrafast Doppler as well as its main parameters. Firstly, we summarize the physical principles of unfocused wave imaging. Then, we present the Doppler signal processing main steps. Particularly, we explain the practical implementation of the critical tissue/blood flow separation algorithms and on the extraction of velocities from these filtered data. This theoretical description is supplemented by in vitro experiences. A tissue phantom embedding a canal with flowing blood-mimicking fluid is imaged with a research programmable ultrasound system. A blood flow image is obtained and the flow characteristics are displayed for several pixels in the canal. Finally, a review of in vivo applications is proposed, showing examples in several organs such as carotids, kidney, thyroid, brain and heart.

This protocol shows how to apply ultrafast ultrasound Doppler imaging to quantify blood flows. After a 1 s long acquisition, the experimenter has access to a movie of the full field of view with axial velocity values for each pixel every &#8776;0.3 ms (depending on the ultrasound time of flight).

تصوير تدفق الدم مع دوبلر فائق السرعة

The pulsed-Doppler effect is the main technique used in clinical echography to assess blood flow. Applied with conventional focused ultrasound Doppler ...