A simple hairpin DNA sensor for label-free detection of sub-attomole DNA target

In this paper, we explored a label-free, ultrasensitive and simple method of DNA detection based on hairpin DNA via a high-resolution surface plasmon resonance (SPR). Using this simple direct hybridization system, a detection level of 0.5 fM was obtained and the reason of the high sensitivity was discussed. Moreover, the prepared DNA sensor could also discriminate single-base mismatched target and was amenable to study the effect of mismatch position in target DNA. From the results, it can be seen that mutation in the center of target DNA had a greater influence on the hybridization. Then, a simple, inexpensive, high sensitive and excellent selective DNA sensor was developed.