המחברים מודים בתודה טום רובינסון לקריאה הוכחה של כתב היד, ג Bärtschi וה &#39;בנץ להקמת מערכת בקרת לחץ שהותקן. אנחנו רוצים גם להכיר בשימוש במתקן חדר הנקי הראשון ומרכז האור מיקרוסקופית (LMC), שניהם במכון הטכנולוגי של ציריך. העבודה מומנה על ידי חברת מרק סרונו והמועצה האירופית למחקר (ERC) תחת תכנית המסגרת ה -7 (ERC החל גרנט, פרויקט לא. 203,428, nμLIPIDs).

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החוקרים מצהירים כי אין להם אינטרסים כלכליים מתחרים.

טכנולוגית מיקרופלואידיקה פתחה אפשרויות חדשות ומרתקות לניתוח תא בודד. בפרט, את האפשרות למלכודת ולשתק את התאים בנפרד על ידי כלים microfluidic אפשרה מחקרים לטווח קצר וארוך שיטתיים על מאפייני תא בודד ותגובה. בנוסף, אנקפסולציה של תאים בmicrodroplets תדירות גבוהה, שנוצר על שבב אלקטרו?...

מחקרים רבים בעבר חשפו הבדלי תא אל התא בתוך אוכלוסיית תאים גדולה 1-3, בפרט איתות מעבדת 4, או הכמויות של ביומולקולות תאית כגון חלבונים 5,6, מטבוליטים, וcofactors 7,8. heterogeneities אלה נחשבים חשובים ביסודו להסתגלות תאים והתפתחות 9, אבל גם לשחק תפקיד מרכזי בהופעתה וטיפול במחלות כגון סרטן 10-13. לכן, מחקרים ברמת התא הבודד הם עניין גבוה במחקר ביולוגי ותרופתי, במיוחד אם מחקרים אלה חושפים את תגובות תאים השונות לאחר טיפול עם חומרים כימיים ביו. בשנים האחרונות, רבות פלטפורמות אנליטיים פותחו המאפשרות ניתוח של תאי חיים בודדים או את ההרכב הכימי של התוכן הסלולרי. בעוד תא ניאון מיון מופעל (FACS) הוא הזהב standard לניתוח מאוד תפוקה גבוהה של תאי חיים בודדים, השיטה לא יכולה להיות מועסק לכימות של תרכובות תאיים או מופרשים. הופעתה של פלטפורמות microfluidic הבטיחה אסטרטגיות אנליטיות חדשניות למיצוב, טיפול ומעקב של תאים בודדים. אבן דרך במיקרופלואידיקה הושגה עם השילוב של שסתומים PDMS גמישים הבינו ידי Quake ועמיתים לעבודה 14,15. שסתומים אלו יעילים מכיוון שהם יכולים לבודד אזורים בשבב, לדוגמא להפריד בין שתי תרבויות 16. יתר על כן, הם רלוונטיים במיוחד לניתוח תא בודד, ולכן לעזור להפחית בעיות דילול אנליטי. כוחה של גישה זו לניתוח תא בודד הודגם לאחרונה על ידי הנסן ועמיתים לעבודה, שניתח את ביטוי גנים ממאה תאים בודדים ב17 מקבילים. כאשר מיקוד חלבונים ומטבוליטים, הניתוח קשה מאוד עקב חוסר המתאיםשיטות mplification, המספר הגדול של תרכובות שונות בהווה ובווריאציות שלהם בטבע כימי. יתר על כן, רוב ביומולקולות תאית צפויות להיות נוכח במספרים נמוכים עותק בסדר הגודל של כמה עשרות אלף 18, ולכן השיטה אנליטית המשמשת חייבת להיות רגישות גבוהה. מבחני יותר חזקים כגון immunoassays וimmunoassays צמודת אנזים (ELISA) קשים להשתלב במכשירי microfluidic כי הם דורשים כמה כביסה ושלבי דגירה, כמו גם חוסר תנועת פני השטח. בשל אתגרים אלה, אין זה מפתיע שרק כמה דוגמאות שדווחו בו חלבונים או מטבוליטים היו לכמת ברמת התא הבודד. לדוגמא, מחקרים על ההפרשה של תרכובות ניאון דווחו 19,20. לאחרונה, היישום עם ELISA הוצג לניתוח חלבונים מופרשים (nonfluorescent) מתרבית תאים (THP-1 תאים) 21 ויחידה (immune) תאים 10. מיקוד חלבונים תאיים, שי et al. פיתח מכשיר microfluidic שאפשר זיהוי של חלבונים תאיים לניתוח של מסלולי איתות בתאים סרטניים באמצעות immunoassay 11. עם זאת, רק כמויות יחסי של חלבונים שהיו נחושות ולא הגברה אנזימטית שימשה כדי להגדיל את האות לחלבוני שפע נמוך. לאחרונה, הצלחנו לשלב microdevice השמנה תא בודד עם מבחני הקרינה 8 וimmunoassays 22 (איור 1). תאים לכודים באופן פסיבי במבני משוכת microsized, המאפשרים אספקה ​​והחלפה (מהירה) של מדיום וחומרים כימיים אחרים ללא כל תנועה של התאים. שסתום בצורת טבעת סביב כל מלכודת מאפשר בידוד של התא בנפח קטן מאוד (&quot;microchamber&quot;). שסתום זה מונע מייד לאחר החדרת חיץ תא lysing (hypoosmolar), שהואNCE מניעת מולקולות תאיים או מולקולות מופרשים כדי לפזר משם. והכי חשוב, בשל גודלו הקטן של הנפח (625 pl) דילול גדול של המולקולות הוא התחמק. יתר על כן, מאז תמוגה וניתוח מבוצעים באותה התנוחה בשבב, אין אובדן של analytes בשל תחבורה. תכנון השבבים המתוארים כאן כולל 8 שורות לסירוגין של או 7 או 8 microchambers, בהיקף של 60 microchambers. התאים הם מופעלים בשורות, כך שזיהום צולב לאורך קו מנועה. הפלטפורמה יכולה לשמש בשילוב עם מבחני הקרינה, כמו גם מבחני חיסוניים (1D איור). באפשרות השנייה, הקמנו פרוטוקולים לחוסר תנועה של הנוגדנים, אשר עולים בקנה אחד עם ייצור השבבים ותהליך ההרכבה. לפיכך הפלטפורמה פותחת את הדרך למבחנים רגישים, אמינים וכמותיים ברמת התא הבודד. עד עכשיו, יש לנו השתמשתי במכשיר לניתוח של iאנזימי ntracellular והמופרשים (כימות יחסי על ידי מבחני האנזימטית), cofactors תאיים, חלבונים ומולקולות קטנות (כימות מוחלטת על ידי מבחני נקודת סיום או ELISA). בחלק הבא, אנו מתארים את תהליך ייצור שבבים באמצעות יתוגרפיה רב שכבתית רכה והפרוטוקולים לדפוסים של הנוגדנים באמצעות הדפסת microcontact וכימיה של פני השטח. בנוסף, כמה דוגמאות לשימוש בשבב ופעולות מקבלות.

<table><tbody><tr><td>&lt;strong&gt;REAGENTS:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Name of the Reagent</td><td>Company</td><td>Catalogue Number</td><td>Comments (optional)</td></tr><tr><td>SU-8 2015</td><td>MicroChem Corp. (Netwon, MA)</td><td>n.a.</td><td></td></tr><tr><td>1H,1H,2H,2H-Perfluorodecyl-dimethylchloro-silane</td><td>ABCR (Karlsruhe, Germany)</td><td>AB103608</td><td></td></tr><tr><td>4-Methylumbelliferyl &amp;beta;-D-N,N&amp;prime;-diacetylchitobioside hydrate</td><td>Sigma Aldrich</td><td>M9763</td><td></td></tr><tr><td>Acetone</td><td>Merck VWR (Darmstadt, Germany)</td><td>100014</td><td></td></tr><tr><td>Avidin</td><td>AppliChem (Axon Lab AG)</td><td>A-2568</td><td></td></tr><tr><td>AZ 1518</td><td>AZ Electronic Materials (Wiesbaden, Germany)</td><td>n.a.</td><td></td></tr><tr><td>AZ 726 developer</td><td>AZ Electronic Materials (Wiesbaden, Germany)</td><td>n.a.</td><td></td></tr><tr><td>Bovine serum albumin</td><td>Sigma Aldrich</td><td>A-4503</td><td></td></tr><tr><td>Bovine serum albumin, biotin</td><td>Sigma Aldrich</td><td>A-8549</td><td></td></tr><tr><td>Cell dissociation buffer</td><td>Invitrogen</td><td>13151-014</td><td></td></tr><tr><td>Hexamethyldisilazane (HDMS)</td><td>Sigma Aldrich</td><td>40215</td><td></td></tr><tr><td>Hydrochloric acid</td><td>Fluka</td><td>84422</td><td></td></tr><tr><td>Isopropanol</td><td>Merck VWR (Darmstadt, Germany)</td><td>109634</td><td></td></tr><tr><td>Magnesium chloride hexahydrate</td><td>Fluka</td><td>63068</td><td></td></tr><tr><td>MR developer 600</td><td>Microresist technology GmbH (Berlin, Germany)</td><td>n.a.</td><td></td></tr><tr><td>PBS</td><td>Invitrogen</td><td>10010-031</td><td></td></tr><tr><td>PLL-g-PEG grafted</td><td>SuSoS, (D&amp;uuml;bendorf, Switzerland)</td><td>n.a.</td><td></td></tr><tr><td>PLL-g-PEG grafted biotin</td><td>SuSoS, (D&amp;uuml;bendorf, Switzerland)</td><td>n.a.</td><td></td></tr><tr><td>Potassium chloride</td><td>Fluka</td><td>60132</td><td></td></tr><tr><td>Protein G, biotin</td><td>Sigma Fine Chemicals</td><td>41624</td><td></td></tr><tr><td>Silicon wafer</td><td>Si-Mat (Kaufering, Germany)</td><td>n.a.</td><td></td></tr><tr><td>Sylgard 184 Silicone Elastomer Kit (PDMS)</td><td>Dow Corning</td><td>39100000</td><td></td></tr><tr><td>Tris(hydroxymethyl)-aminomethan</td><td>Biorad</td><td>1610716</td><td></td></tr><tr><td>Tween 20</td><td>Biorad</td><td>1706531</td><td></td></tr><tr><td>&lt;strong&gt;EQUIPMENT:&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Material Name</td><td>Company</td><td>Catalogue Number</td><td>Comments (optional)</td></tr><tr><td>0.22 &amp;micro;m PES syringe filter</td><td>TRP</td><td>99722</td><td></td></tr><tr><td>1/1.5 mm biopsy puncher</td><td>Miltex, York PA</td><td>33-31AA/33-31A</td><td></td></tr><tr><td>Cell Trics filter 20 &amp;micro;m</td><td>Partec</td><td>04-004-2325</td><td></td></tr><tr><td>Centrifuge Sigma 3-18K</td><td>Kuehner</td><td>n.a.</td><td></td></tr><tr><td>Hotplate HP 160 III BM</td><td>Sawatec, Sax, Switzerland</td><td>n.a.</td><td></td></tr><tr><td>MA-6 mask aligner</td><td>Karl Suess</td><td>n.a.</td><td></td></tr><tr><td>Multizoom AZ100M microscope</td><td>Nikon Corporation</td><td>n.a.</td><td></td></tr><tr><td>Photomask</td><td>Microlitho, Essex, U.K.</td><td>n.a</td><td></td></tr><tr><td>Plasma Cleaner PDC-32G</td><td>Harrick</td><td>n.a.</td><td></td></tr><tr><td>Spin coater Modell WS-400 BZ-6NPP/LITE</td><td>Laurell</td><td>n.a.</td><td></td></tr><tr><td>Spin Modules SM 180 BM</td><td>Sawatec, Sax, Switzerland</td><td>n.a.</td><td></td></tr><tr><td>Step profiler Dektak XT Advanced</td><td>Bruker</td><td>n.a.</td><td></td></tr><tr><td>Syringe pump neMESYS</td><td>Cetoni</td><td>n.a.</td><td></td></tr></tbody></table>

a microfluidic chip for the versatile chemical analysis of single cells

אנו מציגים מכשיר microfluidic המאפשר קביעת כמותית של ביומולקולות תאית בתאים בודדים מרובים במקביל. לצורך כך, התאים לכודים באופן פסיבי באמצע microchamber. עם ההפעלה של שכבת הבקרה, התא מבודד מהנפח שמסביב בחדר קטן. הנפח המקיף לאחר מכן ניתן להחליף מבלי להשפיע על התאים המבודדים. עם זאת, על פתיחה וסגירה קצרות של החדר, הפתרון בתא יכול להיות מוחלף בתוך כמה מאה אלפיות שנייה. בשל ההפיכות של התאים, יכול להיחשף לתאים ברצף פתרונות שונים באופנה לשליטה מאוד, למשל עבור דגירה, כביסה, ולבסוף, תמוגה תא. Microchambers הסגור היטב יאפשר השמירה של lysate, למזער ולשלוט בדילול לאחר תמוגה תא. מאז תמוגה וניתוח להתרחש באותו המיקום, רגישות גבוהה נשמר משום שאין ד נוסףilution או אובדן analytes מתרחש במהלך הובלה. עיצוב microchamber לכן מאפשר ניתוח אמין לשחזור של מספרי עותק קטנים מאוד של מולקולות תאיים (attomoles, zeptomoles) שוחררו מהתאים בודדים. יתר על כן, ניתן לארגן microchambers רבים בפורמט מערך, המאפשר הניתוח של תאים רבים בבת אחת, בהתחשב בעובדה שמכשירים אופטיים מתאימים המשמשים לניטור. יש לנו כבר השתמשתי בפלטפורמה למחקרי הוכחה של הקונספט לנתח חלבונים תאיים, אנזימים, cofactors ושליחים שני באופן כימות או יחסי או מוחלט.

הפלטפורמה שלנו היא מסוגלת לנתח מגוון של תאיים, כמו גם מולקולות מופרשים בהווה באו המיוצר על ידי תאים בודדים. כאן, אנו רוצים להציג מחקרי ירושלים שונים כדי להדגיש את המגוון של מבחני אפשריים. אנו נותנים דוגמא לאנזים מופרש (איור 5 א), כמו גם אנזים תאיים (איור 5)</s...

Watch this Scientific Journal Video about A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells at JoVE.com

A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells

במאמר זה אנו מציגים שבב microfluidic לניתוח תא בודד. זה מאפשר כימות של חלבונים תאיים, אנזימים, cofactors, ושליחים שני באמצעות מבחני או immunoassays ניאון.

שבב microfluidic לניתוח הכימי תכליתי של תאים בודדים

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this ...

a-microfluidic-chip-for-versatile-chemical-analysis-single

Research

JoVE Journal

Bioengineering

14.8K Views.  ETH Zurich, Switzerland.  במאמר זה אנו מציגים שבב microfluidic לניתוח תא בודד. זה מאפשר כימות של חלבונים תאיים, אנזימים, cofactors, ושליחים שני באמצעות מבחני או immunoassays ניאון. 

Video: A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells

Counting Proteins in Single Cells with Addressable Droplet Microarrays

Often cellular behavior and cellular responses are analyzed at the population level where the responses of many cells are pooled together as an average result masking the rich single cell behavior within a complex population. Single cell protein detection and quantification technologies have made a remarkable impact in recent years. Here we describe a practical and flexible single cell analysis platform based on addressable droplet microarrays. This study describes how the absolute copy numbers of target proteins may be measured with single cell resolution. The tumor suppressor p53 is the most commonly mutated gene in human cancer, with more than 50% of total cancer cases exhibiting a non-healthy p53 expression pattern. The protocol describes steps to create 10 nL droplets within which single human cancer cells are isolated and the copy number of p53 protein is measured with single molecule resolution to precisely determine the variability in expression. The method may be applied to any cell type including primary material to determine the absolute copy number of any target proteins of interest.

Here we present addressable droplet microarrays (ADMs), a droplet array based method able to determine absolute protein abundance in single cells. We demonstrate the capability of ADMs to characterize the heterogeneity in expression of the tumor suppressor protein p53 in a human cancer cell line.

ספירת חלבונים בתאים יחיד עם Droplet למיעון מיקרו-מערכים

Often cellular behavior and cellular responses are analyzed at the population level where the responses of many cells are pooled together as an average ...

Cancer Research

Fluorescence detection methods for microfluidic droplet platforms

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that accompany system miniaturisation. Advantages include the ability to efficiently process nano- to femoto- liter volumes of sample, facile integration of functional components, an intrinsic predisposition towards large-scale multiplexing, enhanced analytical throughput, improved control and reduced instrumental footprints.1
In recent years much interest has focussed on the development of droplet-based (or segmented flow) microfluidic systems and their potential as platforms in high-throughput experimentation.2-4 Here water-in-oil emulsions are made to spontaneously form in microfluidic channels as a result of capillary instabilities between the two immiscible phases. Importantly, microdroplets of precisely defined volumes and compositions can be generated at frequencies of several kHz. Furthermore, by encapsulating reagents of interest within isolated compartments separated by a continuous immiscible phase, both sample cross-talk and dispersion (diffusion- and Taylor-based) can be eliminated, which leads to minimal cross-contamination and the ability to time analytical processes with great accuracy. Additionally, since there is no contact between the contents of the droplets and the channel walls (which are wetted by the continuous phase) absorption and loss of reagents on the channel walls is prevented.
Once droplets of this kind have been generated and processed, it is necessary to extract the required analytical information. In this respect the detection method of choice should be rapid, provide high-sensitivity and low limits of detection, be applicable to a range of molecular species, be non-destructive and be able to be integrated with microfluidic devices in a facile manner. To address this need we have developed a suite of experimental tools and protocols that enable the extraction of large amounts of photophysical information from small-volume environments, and are applicable to the analysis of a wide range of physical, chemical and biological parameters. Herein two examples of these methods are presented and applied to the detection of single cells and the mapping of mixing processes inside picoliter-volume droplets. We report the entire experimental process including microfluidic chip fabrication, the optical setup and the process of droplet generation and detection.

Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.

שיטות גילוי הקרינה לפלטפורמות אגל microfluidic

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that ...

Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the first, synthesis of ultra-small copper nanoclusters is described. The second example provides their utility for investigating time resolved kinetics of chemical reactions by analyzing gold nanoparticle formation using in situ X-ray absorption spectroscopy. The final example demonstrates continuous flow catalysis of reactions inside millifluidic channel coated with nanostructured catalyst.

Millifluidic devices are utilized for controlled synthesis of nanomaterials, time-resolved analysis of reaction mechanisms and continuous flow catalysis.

Millifluidics לסינתזה כימית וזמן נפתר מכניסטית לימודים

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the ...

A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min&#160;of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.

We present a microfluidic-based electrochemical biochip for DNA hybridization detection. Following ssDNA probe functionalization, the specificity, sensitivity, and detection limit are studied with complementary and non-complementary ssDNA targets. Results illustrate the influence of the DNA hybridization events on the electrochemical system, with a detection limit of 3.8 nM.

Biochip אלקטרוכימי מבוסס Microfluidic לניתוח הכלאה DNA ללא תווית

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration ...

A Microfluidic Chip for ICPMS Sample Introduction

This protocol discusses the fabrication and usage of a disposable low cost microfluidic chip as sample introduction system for inductively coupled plasma mass spectrometry (ICPMS). The chip produces monodisperse aqueous sample droplets in perfluorohexane (PFH). Size and frequency of the aqueous droplets can be varied in the range of 40 to 60 &#181;m and from 90 to 7,000&#160;Hz, respectively. The droplets are ejected from the chip with a second flow of PFH and remain intact during the ejection. A custom-built desolvation system removes the PFH and transports the droplets into the ICPMS. Here, very stable signals with a narrow intensity distribution can be measured, showing the monodispersity of the droplets. We show that the introduction system can be used to quantitatively determine iron in single bovine red blood cells. In the future, the capabilities of the introduction device can easily be extended by the integration of additional microfluidic modules.

We present a discrete droplet sample introduction system for inductively coupled plasma mass spectrometry (ICPMS). It is based on a cheap and disposable microfluidic chip that generates highly monodisperse droplets in a size range of 40&#8722;60 &#181;m at frequencies from 90 to 7,000 Hz.

שבב microfluidic למבוא לדוגמא ICPMS

This protocol discusses the fabrication and usage of a disposable low cost microfluidic chip as sample introduction system for inductively coupled plasma ...

A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet high-throughput, method to perform single-cell culture experiments. Here, we report a microfluidic chip-based strategy for high-efficiency single-cell isolation (~77%) and demonstrate its capability of performing long-term single-cell culture (up to 7 d) and cellular heterogeneity analysis using clonogenic assay. These applications were demonstrated with KT98 mouse neural stem cells, and A549 and MDA-MB-435 human cancer cells. High single-cell isolation efficiency and long-term culture capability are achieved by using different sizes of microwells on the top and bottom of the microfluidic channel. The small microwell array is designed for precisely isolating single-cells, and the large microwell array is used for single-cell clonal culture in the microfluidic chip. This microfluidic platform constitutes an attractive approach for single-cell culture applications, due to its flexibility of adjustable cell culture spaces for different culture strategies, without decreasing isolation efficiency.

Here, we present a protocol for isolating and culturing single cells with a microfluidic platform, which utilizes a new microwell design concept to allow for high-efficiency single cell isolation and long-term clonal culture.

פלטפורמת Microfluidic עבור בידוד תפוקה גבוהה מתא בודד ותרבות

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

Designing Microfluidic Devices for Studying Cellular Responses Under Single or Coexisting Chemical/Electrical/Shear Stress Stimuli

Microfluidic devices are capable of creating a precise and controllable cellular micro-environment of pH, temperature, salt concentration, and other physical or chemical stimuli. They have been commonly used for in vitro cell studies by providing in vivo like surroundings. Especially, how cells response to chemical gradients, electrical fields, and shear stresses has drawn many interests since these phenomena are important in understanding cellular properties and functions. These microfluidic chips can be made of glass substrates, silicon wafers, polydimethylsiloxane (PDMS) polymers, polymethylmethacrylate (PMMA) substrates, or polyethyleneterephthalate (PET) substrates. Out of these materials, PMMA substrates are cheap and can be easily processed using laser ablation and writing. Although a few microfluidic devices have been designed and fabricated for generating multiple, coexisting chemical and electrical stimuli, none of them was considered efficient enough in reducing experimental repeats, particular for screening purposes. In this report, we describe our design and fabrication of two PMMA-based microfluidic chips for investigating cellular responses, in the production of reactive oxygen species and the migration, under single or coexisting chemical/electrical/shear stress stimuli. The first chip generates five relative concentrations of 0, 1/8, 1/2, 7/8, and 1 in the culture regions, together with a shear stress gradient produced inside each of these areas. The second chip generates the same relative concentrations, but with five different electric field strengths created within each culture area. These devices not only provide cells with a precise, controllable micro-environment but also greatly increase the experimental throughput.

Micro-fabricated devices integrated with fluidic components provide an in vitro platform for cell studies mimicking the in vivo micro-environment. We developed polymethylmethacrylate-based microfluidic chips for studying cellular responses under single or coexisting chemical/electrical/shear stress stimuli.

עיצוב מכשירי microfluidic ללימוד ותגובות ניידות תחת בית או להתאבדות כימית / חשמל / שאר מתח גירויים

Microfluidic devices are capable of creating a precise and controllable cellular micro-environment of pH, temperature, salt concentration, and other ...

Microfluidic Platform with Multiplexed Electronic Detection for Spatial Tracking of Particles

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to spatially fractionate the sample based on a biological property of interest. For the resultant spatial distribution to be used as the assay readout, microfluidic devices are often subjected to microscopic analysis requiring complex instrumentation with higher cost and reduced portability. To address this limitation, we have developed an integrated electronic sensing technology for multiplexed detection of particles at different locations on a microfluidic chip. Our technology, called Microfluidic CODES, combines Resistive Pulse Sensing with Code Division Multiple Access to compress 2D spatial information into a 1D electrical signal. In this paper, we present a practical demonstration of the Microfluidic CODES technology to detect and size cultured cancer cells distributed over multiple microfluidic channels. As validated by the high-speed microscopy, our technology can accurately analyze dense cell populations all electronically without the need for an external instrument. As such, the Microfluidic CODES can potentially enable low-cost integrated lab-on-a-chip devices that are well suited for the point-of-care testing of biological samples.

We demonstrate a microfluidic platform with an integrated surface electrode network that combines resistive pulse sensing (RPS) with code division multiple access (CDMA), to multiplex detection and sizing of particles in multiple microfluidic channels.

פלטפורמת microfluidic עם איתור Multiplexed אלקטרוני למערכות מעקב מרחבית של חלקיקים

Microfluidic processing of biological samples typically involves differential manipulations of suspended particles under various force fields in order to ...

Establishing Single-Cell Based Co-Cultures in a Deterministic Manner with a Microfluidic Chip

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases including cancer. However, it is challenging to clarify the complex mechanism of intercellular interactions in highly heterogeneous cell populations using conventional co-culture systems because the heterogeneity of the cell subpopulation is obscured by the average values; the conventional co-culture systems can only be used to describe the population signal, but are incapable of tracking individual cells behavior. Furthermore, conventional single-cell experimental methods have low efficiency in cell manipulation because of the Poisson distribution. Microfabricated devices are an emerging technology for single-cell studies because they can accurately manipulate single cells at high-throughput and can reduce sample and reagent consumption. Here, we describe the concept and application of a microfluidic chip for multiple single-cell co-cultures. The chip can efficiently capture multiple types of single cells in a culture chamber (~46%) and has a sufficient culture space useful to study the cells&#39; behavior (e.g., migration, proliferation, etc.) under cell-cell interaction at the single-cell level. Lymphatic endothelial cells and oral squamous cell carcinoma were used to perform a single-cell co-culture experiment on the microfluidic platform for live multiple single-cell interaction studies.

This report describes a microfluidic chip-based method to set up a single cell culture experiment in which high-efficiency pairing and microscopic analysis of multiple single cells can be achieved.

הקמת תרבויות בודדות מבוססות-משותפות באופן דטרמיניסטי עם שבב מיקרופלואידיסי

Cell co-culture assays have been widely used for studying cell-cell interactions between different cell types to better understand the biology of diseases ...

Generation of Dynamical Environmental Conditions using a High-Throughput Microfluidic Device

Mimicking in vivo environmental conditions is crucial for in vitro studies on complex life machinery. However, current techniques targeting live cells and organs are either highly expensive, like robotics, or lack nanoliter volume and millisecond time accuracy in liquid manipulation. We herein present the design and fabrication of a microfluidic system, which consists of 1,500 culture units, an array of enhanced peristaltic pumps and an on-site mixing modulus. To demonstrate the capacities of the microfluidic device, neural stem cell (NSC) spheres are maintained in the proposed system. We observed that when the NSC sphere is exposed to CXCL in day 1 and EGF in day 2, the round-shaped conformation is well maintained. Variation in the input order of 6 drugs causes morphological changes to the NSC sphere and the expression level representative marker for NSC stemness (i.e., Hes5 and Dcx). These results indicate that dynamic and complex environmental conditions have great effects on NSC differentiation and self-renewal, and the proposed microfluidic device is a suitable platform for high throughput studies on the complex life machinery.

We present a microfluidic system for high throughput studies on complex life machinery, which consists of 1500 culture units, an array of enhanced peristaltic pumps and an on-site mixing modulus. The microfluidic chip allows for the analysis of the highly complex and dynamic micro-environmental conditions in vivo.

יצירת תנאי סביבה דינמיים באמצעות מכשיר מיקרופלואידי בעל תפוקה גבוהה

Mimicking in vivo environmental conditions is crucial for in vitro studies on complex life machinery. However, current techniques targeting live cells and ...