Apologies, I was writing this while balancing my son on one arm and mixed up some simplification with good old-fashioned mistakes!

I'll nip this in the bud and say "DNA particles" was definitely the wrong word.

You are correct, the Bromine here isn't really the problem; the fact that any intercalculation with DNA occurs is the main problem. Is it Bromine's fault? Not particularly, but it's an accessory in this instance. Based on anecdotal evidence it's common to the electrophoresis process.

My reason for bringing this up is just one of those relatable stories (/s) about why I also don't like working with Bromine (even if contextually it's not Bromine's fault, we love you Bromine!)