Biomedical Engineering Department, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109, United States.
ACS Nano. 2010 Oct 26;4(10):5897-904. doi: 10.1021/nn1021988.
We developed highly sensitive and specific nanosensors based on quantum dots (QDs) and DNAzyme for multiplexed detection of heavy metal ions in liquid. The QDs were coated with a thin silica layer for increased stability and higher quantum yield while maintaining a relatively small size for highly efficient energy transfer. The QD-DNAzyme nanosensors were constructed by conjugating quencher-labeled DNAzymes onto the surface of carboxyl-silanized QDs. In the presence of metal ions, the emission is restored due to the cleavage of DNAzymes. The detection could be completed within 25 min with a single laser excitation source. The detection limit of 0.2 and 0.5 nM was experimentally achieved for Pb(2+) and Cu(2+), respectively, which is a 50- and 70-fold improvement over the recent results obtained with dye molecules. Multiplexed detection was also demonstrated using two different colors of QDs, showing negligible cross-talk between the Pb(2+) detection and Cu(2+) detection.
我们开发了基于量子点（QDs）和 DNA zyme 的高灵敏度和特异性纳米传感器，用于在液体中多重检测重金属离子。为了提高稳定性和更高的量子产率，同时保持相对较小的尺寸以实现高效能量转移，我们在 QD 表面涂覆了一层薄的二氧化硅层。QD-DNAzyme 纳米传感器是通过将淬灭标记的 DNAzyme 偶联到羧基硅烷化 QD 的表面来构建的。在金属离子存在下，由于 DNAzyme 的切割，发射得到恢复。使用单个激光激发源，检测可在 25 分钟内完成。对于 Pb(2+)和 Cu(2+)，实验上分别实现了 0.2 和 0.5 nM 的检测限，这比最近使用染料分子获得的结果提高了 50 倍和 70 倍。使用两种不同颜色的 QD 还实现了多重检测，表明 Pb(2+)检测和 Cu(2+)检测之间几乎没有串扰。
