What is the reasoning why acidic dyes stain only the background and not the cells?

As one of the most famous scientists, Marie Curie has become an icon in the scientific world and has received tributes from across the globe, even in the realm of pop culture. In a 2009 poll carried out by New Scientist, she was voted the "most inspirational woman in science". Curie received 25.1 percent of all votes cast, nearly twice as many as second-place Rosalind Franklin (14.2 per cent).  Hope I helped! :)