A popular tool used in thousands of medical sensors might not actually work at all.
April 15, 2026
Original Paper
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
The Takeaway
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.
From the abstract
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,