A novel electrically magnetic-controllable electrochemical biosensor for the ultra sensitive and specific detection of attomolar level oral cancer-related microRNA.

Non-invasive early diagnosis of oral cancer is the most effective means to reduce mortality rate from this disease. In this paper, we described a novel magnetic-controllable electrochemical RNA biosensor for the ultra sensitive and specific detection of oral cancer-related microRNA (miRNA) based on a home-made electrically magnetic-controllable gold electrode. The electrically magnetic-controllable gold electrode combined the merits of heated electrode and magnetic electrode, has notable advantage such as that the strength and direction of the magnetic field and the temperature of the electrode's surface can be easily regulated. The advantage of electrically magnetic-controllable gold electrode, as well as the utilization of "junction-probe" strategy and magnetic beads (MBs)-based enzymatic catalysis amplification, make the biosensor has ultra-high sensitivity and discrimination ability even for the detection of similar miRNAs. It can be used to detect as low as 0.22 aM (2.2 × 10(-19)M) of oral cancer-related miRNA with a recovery of 93-108% and a RSD<6 (n=5). The high sensitivity and selectivity, as well as the easiness of fabrication, operational convenience, short analysis time, good stability and re-usability, make the biosensor a promising alternative for the early point-of-care diagnosis of oral cancer. The success of the biosensor also leads to a great potential in the development of biosensor for the early diagnosis of other diseases.