Question: How do I study a large tissue specimen (greater than 6.5 mm x 6.5 mm) using Visium?
Answer: We understand the significance of studying the whole precious tissue specimen.
Trimming of the OCT block to remove access OCT may be needed to achieve a smaller block size prior to sectioning.
Depending upon the tissue type, scoring of the tissue and placing sections across different capture areas of the slide may be employed if the tissue is too large to fit within a single capture area. Each scored capture area could obtain spatial information for a different part of the tissue sectioned.
For example, using mouse brain in-house, we section the whole brain as normal, but as you get closer to the region of interest you score (shallow) the brain vertically (sagittally) at the midline with a disposable razor blade. As you section the brain, you will generate two sections containing the separated hemispheres and either one or both of the two sides of the hemisphere can placed on the capture area(s). Below is a graphical representation of this as a reference. It is recommended to try out this strategy on a blank block of OCT prior to using actual tissue in order to gain experience with performing this.
Tissue sections can be combined later using the Space Ranger aggr pipeline.