Dit protocol Gegevens methode extracellulaire blaasjes (EV), kleine membraneuze deeltjes vrijgemaakt uit cellen te isoleren, van slechts 10 pl serummonsters. Deze benadering omzeilt de noodzaak van ultracentrifugatie, vereist slechts enkele minuten testtijd en maakt de isolatie van EV uit monsters van beperkte omvang.
Extracellulaire blaasjes (EV's), membraneuze deeltjes die vrijkomen uit verschillende soorten cellen, het bezit van een groot potentieel voor klinische toepassingen. Zij bevatten nucleïnezuur en eiwit lading en worden steeds meer erkend als een middel van intercellulaire communicatie gebruikt door zowel eukaryote en prokaryote cellen. Vanwege hun geringe omvang huidige protocollen voor isolatie van EV vaak tijdrovend, omslachtig en grote monstervolumes en dure apparatuur, zoals een ultracentrifuge nodig. Om deze beperkingen aan te pakken, ontwikkelden we een papieren immunoaffiniteit platform voor het scheiden van subgroepen van EV's dat is gemakkelijk, efficiënt, en vereist monster volumes zo laag als 10 pi. Biologische monsters kunnen direct worden gepipetteerd op papier testzones die chemisch zijn gewijzigd met capture moleculen die een hoge affiniteit voor specifieke EV oppervlakte markers hebben. We valideren de test met behulp van scanning elektronenmicroscopie (SEM), op papier gebaseerde enzym-gekoppelde immunosorbent assays (P-ELISA), en transcriptoomanalyse. Deze papieren apparaten zal de studie van EV's in de kliniek en de instelling onderzoek mogelijk maken om te helpen tot een beter begrip van de EV-functies in gezondheid en ziekte.
Extracellular vesicles (EVs) are heterogeneous membranous particles that range in size from 40 nm to 5,000 nm and are released actively by many cell types via different biogenesis routes1-9. They contain unique and selected subsets of DNA, RNA, proteins, and surface markers from parental cells. Their involvement in a variety of cellular processes, such as intercellular communication10, immunity modulation11, angiogenesis12, metastasis12, chemoresistance13, and the development of eye diseases9, is increasingly recognized and has spurred a great interest in their utility in diagnostic, prognostic, therapeutic, and basic biology applications.
EVs can be classically categorized as exosomes, microvesicles, apoptotic bodies, oncosomes, ectosomes, microparticles, telerosomes, prostatosomes, cardiosomes, and vexosomes, etc., based on their biogenesis or cellular origin. For example, exosomes are formed in multivesicular bodies, whereas microvesicles are generated by budding directly from plasma membrane and apoptotic vesicles are from apoptotic or necrotic cells. However, the nomenclature is still under refined, partly due to a lack of thorough understanding and characterization of EVs. Several methods have been developed to purify EVs, including ultracentrifugation14, ultrafiltration15, magnetic beads16, polymeric precipitation17-19, and microfluidic techniques20-22. The most common procedure to purify EVs involves a series of centrifugations and/or filtration to remove large debris and other cellular contaminants, followed by a final high-speed ultracentrifugation, a process that is expensive, tedious, and nonspecific14,23,24. Unfortunately, technological need for rapid and reliable isolation of EVs with satisfactory purity and efficiency is not yet met.
We have developed a paper-based immunoaffinity device that provides a simple, time- and cost-saving, yet efficient way to isolate and characterize subgroups of EVs22. Cellulose paper cut into a defined shape can be arranged and laminated using two plastic sheets with registered through-holes. In contrast to the general strategy to define the fluid boundary in paper-based devices by printing hydrophobic wax or polymers25-27, these laminated paper patterns are resistant to many organic liquids, including ethanol. Paper test zones are chemically modified to provide stable and dense coverage of capture molecules (e.g., target-specific antibodies) that have high affinity to specific surface markers on EV subgroups. Biological samples can be pipetted directly onto the paper test zones, and purified EVs are retained after rinse steps. Characterization of isolated EVs can be performed by SEM, ELISA, and transcriptomic analysis.
De meest kritische stappen voor een succesvolle isolatie van subgroepen van extracellulaire blaasjes zijn: 1) een goede keuze van papier; 2) stabiele en hoge dekking van vangende moleculen aan het oppervlak van de vezels; 3) de goede behandeling van monsters; en 4) de algemene hygiëne in laboratoria praktijk.
Poreuze materialen zijn gebruikt in vele goedkope en apparatuur vrij assays. Zij kunnen afstembare poriegrootte veelzijdige toepassing, lage kosten en hoge oppervlakte-volume verhoudin…
The authors have nothing to disclose.
Dit werk werd mede ondersteund door de Taiwan National Science Council grants- NSC 99-2320-B-007-005-MY2 (CC) en NSC 101-2628-E-007-011-MY3 (CMC), en de Veterans General ziekenhuizen en Universiteit Systeem van Taiwan Joint Research Program (CC).
Chromatography Paper | GE Healthcare Life Sciences | 3001-861 | Whatman® Grade 1 cellulose paper |
(3-Mercaptopropyl) trimethoxysilane | Sigma Aldrich | 175617 | This chemical reacts with water and moisture and should be applied inside a nitrogen-filled glove bag. Avoid eye and skin contact. Do not breathe fumes or inhale vapors. |
Ethanol | Fisher Scientific | BP2818 | Absolute, 200 Proof, molecular biology grade |
Bovine serum albumin (BSA) | BioShop Canada Inc. | ALB001 | Often referred to as Cohn fraction V. |
N-g-maleimidobutyryloxy succinimide ester (GMBS) | Pierce Biotechnology | 22309 | GMBS is an amine-to-sulfhydryl crosslinker. GMBS is moisture-sensitive. |
Avidin | Pierce Biotechnology | 31000 | NeutrAvidin has 4 binding sites for biotin and its pI value is 6.3, which is more neutral than native avidin |
Biotinylated mouse anti-human anti-CD63 | Ancell | 215-030 | clone AHN16.1/46-4-5 |
biotinylated annexin V | BD Biosciences | 556418 | Annxin V has a high affinity for phosphotidylserine (PS) |
Primary anti-CD9 and secondary antibody | System Biosciences | EXOAB-CD9A-1 | The secondary antibody is horseradish peroxidise-conjugated |
Serum separation tubes | BD Biosciences | 367991 | Clot activator and gel for serum separation |
Annexin V binding buffer | BD Biosciences | 556454 | 10X; dilute to 1X prior to use. |
TMB substrate reagent set | BD Biosciences | 555214 | The set contains hydrogen peroxide and 3,3’,5,5’-tetramethylbenzidine (TMB) |
RNA isolation kit | Life Technologies | AM1560 | MirVana RNA isolation kit |
Polyvinylpyrrolidone-based RNA isolation aid | Life Technologies | AM9690 | Plant RNA isolation aid contains polyvinylpyrrolidone (PVP) that binds to polysaccharides. |
RNA cleanup kit | Qiagen Inc. | 74004 | MinElute RNA cleanup kit is designed for purification of up to 45 μg RNA. |
Plasma chamber | March Instruments | PX-250 | |
Scanning electron microscope | Hitachi Ltd. | S-4300 | |
Desktop scanner | Hewlett-Packard Company | Photosmart B110 | 8-bit color images were captured. Cameras and smart phones may be also used. |
Image-record system | J&H Technology Co | GeneSys G:BOX Chemi-XX8 | 16-bit fluroscence images were captured. Fluroscence microscopes may be also used. |