تشخیص یون های سنگین با استفاده از یک آرایه بیوسنسور میکرومکانیکی خازنی برای نظارت بر محیط زیست؟

Heavy metal ions are major contaminants in present day water supply. In this work the fabrication and evaluation of a DNAzyme functionalized capacitive micromechanical sensor array for the detection of lead ions is presented. The catalytic strand of a “8–17” DNAzyme can cleave a substrate DNA strand that has one ribonucleotide base, in the presence of Pb2+, dissociating the complex into three fragments. The DNAzyme strand is laser printed and immobilized on the sensor surface and hybridized with the substrate strand. When self-cleaving occurs, the surface stress changes, which is then registered as change in the capacitance of the device. The sensor was able to detect 10 μM of Pb2+, whilst in a reverse procedure the re-hybridization of the immobilized catalytic strand with the substrate strand was demonstrated. The reactions were validated by tagging the catalytic strand with FAM (6-carboxyfluorescein), while the substrate strand was tagged with Dabcyl, a quencher.