A novel ratiometric SERS biosensor with one Raman probe for ultrasensitive microRNA detection based on DNA hydrogel amplification

increased with the increase in the concentration of target miRNA 122, thus achieving quantitative detection of miRNA 122. As a consequence, our SERS biosensor could sensitively detect miRNA 122 from 10 aM to 100 pM, and the detection limit was 7.75 aM. Our strategy adopts a novel ratiometric method with one Raman probe to detect miRNA, opening a new avenue for the detection of trace amounts of biological samples with high sensitivity and accuracy.