Overview
This video describes an electroporation-based method for encapsulating siRNA into exosomes. The siRNA-loaded exosomes can then be used for therapeutic applications.
Protocol
1. siRNA Encapsulation into Exosomes by Electroporation
- Pre-chill the electroporation cuvette (see Table of Materials) on ice for 30 min before electroporation.
- Mix 7.0 µg of exosomes (32 µL from 7 x 1012 p/mL stock in PBS) with 0.33 µg of siRNA (12 µL from 2 µM stock in RNase-free water) in the microcentrifuge tube. Make up the volume to 150 µL with citric acid buffer (see Table of Materials). The exosome to siRNA molar ratio is 1:60 in this case.
- Transfer the mixture to electroporation cuvette. Cap the cuvette and place it in the cuvette holder of the electroporator (see Table of Materials). Rotate the turning wheel 180° clockwise.
NOTE: The wheel must be turned completely to the locked position, in order for the cuvette to contact the electrodes. - Select the desired electroporation program (e.g., X-01, X-05, A-20, T-20, T-30, etc.) and start electroporation by pressing the start button.
NOTE: A successful pulse is indicated by showing "OK" on the display. - Once electroporated, remove the cuvette after turning back the wheel 180° counterclockwise. Withdraw the sample from the cuvette with the plastic pipette for further processing.
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Materials
Name | Company | Catalog Number | Comments |
Atto655-siRNA | Eurogentec | SQ-SIRNA | (Labelled-S) UGC-GCU-ACGAUC-GAC-GAU-G55; (UnlabelledAS) CAU-CGU-CGA-UCG-UAGCGC-A55. |
Glass pipettes | Fisher Scientific | 1156-6963 | |
Amaxa Nucleofector I | Lonza | Nucleofector I | With Amaxa’s Nucleofector kits |
Citric acid buffer with EDTA | Mix 0.1954 g citric acid and 0.2087 g disodium phosphate in 50 mL of deionised water. Add EDTA to 0.1 mM. Adjust pH to 4.4. | ||
Microfuge tubes | Starlab | S1615-5500 | 1.5 ml |