Question: Can Visium Spatial Gene Expression Slides be stored post-Immunofluorescence staining?
Answer: Storage of Visium Gene Expression slides with fresh-frozen tissue sections post-Immunofluorescence (IF) staining has not been validated. We strongly recommend following the stopping points provided in the Visium Gene Expression User Guide and proceeding immediately to imaging after IF staining. To avoid imaging delays, optimize imaging parameters before beginning an experiment by leveraging the Imaging Test Slide found in the Visium Accessory Kit.
If a workflow delay cannot be avoided due to hand-off constraints or unexpected events, we recommend following the steps below to minimize the impact of the delay:
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Proceed to imaging as soon as possible post-IF staining to avoid fading the fluorescence signal.
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In case of unforeseen delays, store the slide with the coverslip mounted in a sealed container at 4°C. Keep the slide horizontal with the coverslip side facing up to avoid the shifting of the coverslip. The slide should be kept in the dark before imaging. Wrap the container with foil if needed.
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If transporting the slide, keep the coverslip mounted to avoid drying the tissue sections. Wick away excess mounting media to avoid the coverslip from moving during transport. Place the slide in a slide mailer or cardboard slide holder and then in a sealed bag on wet ice. Ensure the slide is kept flat during transport.
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When ready to proceed with the permeabilization step, remove the coverslip by submerging the slide in the 3X SSC buffer following the IF Staining Demonstrated Protocol. Do not agitate the slide to avoid damaging the tissue. It may take some time for the coverslip to separate after the 4°C storage.
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After coverslip removal, place the slide in a clean Visium Slide Cassette and immediately add 50 µl freshly prepared Wash Buffer along the side of each well. Proceed with permeabilization as soon as possible.
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Carry out the permeabilization step within 24 hours post-IF staining to minimize the impact on assay performance.
Product: Visium for fresh-frozen