The current Covid-19 pandemic has highlighted the need for rapid and accurate quantitative analysis of dangerous pathogens, particularly Sars-Cov-2. Fortunately, our ability to determine the structure of new and dangerous viruses has continued to improve since the invention of polymerase chain reaction (PCR), which enables the production of billions of copies of a single DNA sample. The ‘gold standard’ for DNA detection today is quantitative polymerase chain reaction (qPCR), which combines standard PCR with dye molecules whose fluorescent output increases as the reaction proceeds.