A popular tool used in thousands of medical sensors might not actually work at all.
For years, scientists have used a specific DNA 'aptamer' to build sensors that measure C-reactive protein (CRP), a key marker for inflammation and heart disease. But this study just proved that the tool doesn't even bind to the protein it’s supposed to measure when it's in a normal solution. It turns out the previous 'successes' were likely just a technical error caused by the testing equipment itself. This means that a huge amount of research—and potentially some diagnostic tools—could be based on a complete fluke. It’s a massive warning that we need to double-check the 'standard' tools we rely on for our health. We might have been measuring the wrong thing for years.
A widely used C-Reactive Protein aptamer does not bind C-Reactive Protein in solution, suggesting potential streptavidin-driven artifacts in biosensors
ChemRxiv · chemrxiv.15001875/v1
Aptamer sequences are often reused in diagnostics without independent confirmation of binding activity, although rigorous validation requires quantitative solution-phase testing by orthogonal methods. Here, we re-examined a DNA sequence reported in 2010 to bind C-reactive protein (CRP) with a Kd of 3.5 nM by surface plasmon resonance (SPR) that has since been adopted in many CRP aptasensors. We tested this sequence by two orthogonal solution-phase methods, each in direct and competitive formats,