Mutated DNA strands — even those with only a change in a single nucleobase — can be the cause of serious health problems. Quantifying these mutant DNA strands is particularly challenging when they are present in low concentrations in a patient’s urine or blood samples and must be detected against a large background concentration of wild-type DNA. Now, writing in the Journal of the American Chemical Society, Nils Walter and co-workers report the development of an amplification-free method that they call single-molecule recognition through equilibrium Poisson sampling (SiMREPS).
“We were seeking a powerful tool to detect mutations that are cancer causing, or that make cancer harder to treat,” explains Walter. “One such mutation is found in the epidermal growth factor receptor (EGFR), where a cytosine-to-thymine mutation in the DNA results in substitution of a threonine with a methionine in the protein. The ultimate result of this change is that certain classes of tyrosine kinase inhibitor (TKI) drugs no longer work.”
Read full research highlight in the journal Nature Reviews Materials : Signals from single molecules