Diamond Biosensor for Specific Sequence of DNA with Ultra-high Sensitivity

Hiroshi Uetsuka and Nianjun Yang, the Diamond Research Center of the National Institute of Advanced Industrial Science and Technology (AIST) have fabricated vertically aligned nanowire structure with 10 nm lateral spacing on conductive diamond surfaces, and succeeded in highly sensitive detection of DNA (2 pM) using an electrochemical sensor with the nanowire-structured diamond electrodes. The sensor shows several magnitudes of higher sensitivity than those of electrochemical sensors with conventional electrode materials.

Probe DNAs (single strand: 23 mer) are grafted on the apex of diamond nanowires which are aligned vertically with 10 nm spacing on the conductive diamond electrode. When target DNAs are complementary hybridized with the probe DNAs to make double strand chains, redox current should be decreased since the surface area opened for electrolyte will be decreasing. This is the mechanism to detect specific sequence of DNAs using this electrochemical sensor. Two or three order of magnitude higher sensitivity in comparison with conventional sensors using gold or glassy carbon has been achieved.

Several target DNAs can be detectable by changing sequence of probe DNA. Furthermore, the technology can be applicable for detection and measurement of various diseases and microorganisms, and gives our society a big impact.