Este protocolo detalha um método para isolar vesículas extracelulares (SVE), pequenas partículas membranoso liberados a partir de células, a partir de tão pouco como 10 amostras de soro ul. Esta abordagem evita a necessidade de ultracentrifugação, exige apenas alguns minutos de tempo de ensaio, e permite o isolamento de VE a partir de amostras de volumes limitados.
Vesículas extracelulares (SVE), partículas membranoso liberados a partir de vários tipos de células, realizar um grande potencial para aplicações clínicas. Eles contêm ácido nucleico e proteína de carga e são cada vez mais reconhecido como um meio de comunicação intercelular utilizado por ambos eucariota e células procarióticas. No entanto, devido ao seu pequeno tamanho, os protocolos para o isolamento de veículos eléctricos são muitas vezes moroso, complicado e requer grandes volumes de amostra e equipamento caro, tal como uma ultracentrífuga. Para lidar com essas limitações, nós desenvolvemos uma plataforma de imunoafinidade baseado em papel para separar subgrupos de EVs que é fácil, eficiente e requer volumes de amostra tão baixas como 10 jul. As amostras biológicas podem ser pipetados directamente para zonas de teste de papel que tenham sido quimicamente modificados com moléculas de captura que têm uma afinidade elevada para marcadores de superfície específicos EV. Immunosorben ligado a enzima Nós validar o ensaio por meio de microscopia eletrônica de varredura (MEV), com base em papelensaios t (P-ELISA), e análise de transcriptoma. Estes dispositivos baseados em papel permitirá o estudo de EVs na clínica e no ambiente de pesquisa para ajudar a avançar a nossa compreensão das funções EV na saúde e na doença.
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.
Os passos mais críticos para o isolamento bem sucedido de subgrupos de vesículas extracelulares são: 1) uma boa escolha de papel; 2) uma cobertura estável e elevada de moléculas de captura na superfície das fibras de papel; 3) manuseio adequado de amostras; e 4) práticas de higiene geral de laboratório.
Os materiais porosos têm sido utilizados em muitos ensaios de baixo custo e sem equipamento. Eles podem ter o tamanho de poro sintonizável, funcionalidade versátil, baixo custo e a…
The authors have nothing to disclose.
Este trabalho foi financiado em parte pelo Conselho Nacional de Ciência Taiwan grants- NSC 99-2320-B-007-005-MY2 (CC) e NSC 101-2628-E-007-011-MY3 (CMC), e do Veterans General Hospitais e University System of Taiwan Programa Comum de Investigação (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. |