What does 'single-molecule detection' mean for miRNA testing?

Single-molecule detection means that the measurement system can detect and count individual miRNA molecules one at a time, rather than requiring millions of copies (as PCR does). The Yenos nanopore platform threads each individual miRNA molecule tagged with an osmium metalorganic probe through a nanopore, generating a unique electrical signature for that single molecule. By counting how many cancer-associated miRNA molecules pass through the nanopores during a measurement period, the system quantifies miRNA at femtomolar (10⁻¹⁵ mol/L) concentrations — far below the threshold detectable by PCR without amplification. Single-molecule detection is also why there is no amplification noise and why data overlap between cancer and healthy populations is zero.