Question: Does mRNA transcript diffusion occur with Visium?
Answer: Following the Visium protocol, we have not observed significant transcript diffusion between spots covered with tissue. We believe the tissue itself is physically prohibiting the diffusion. It is common to see lateral diffusion of transcripts captured by spots outside the tissue section. This will not affect your results as these spots are excluded during the analysis. The rate of diffusion outside of the tissue section will be affected by tissue type, the embedding medium used (using something other than OCT), and freezing method. 10x will share a Technical Note including data on this topic in July of 2020.