Wang Joseph, Liu Guodong, Merkoçi Arben
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001, USA.
J Am Chem Soc. 2003 Mar 19;125(11):3214-5. doi: 10.1021/ja029668z.
Nucleic-acid hybridization assays based on the use of different inorganic-colloid (quantum dots) nanocrystal tracers for the simultaneous electrochemical measurements of multiple DNA targets are described. Three encoding nanoparticles (zinc sulfide, cadmium sulfide, and lead sulfide) are used to differentiate the signals of three DNA targets in connection to stripping-voltammetric measurements of the heavy metal dissolution products. These products yield well-defined and resolved stripping peaks at -1.12 V (Zn), -0.68 V (Cd), and -0.53 V (Pb) at the mercury-coated glassy-carbon electrode (vs Ag/AgCl reference). The position and size of these peaks reflect the identity and level of the corresponding DNA target. The multi-target detection capability is coupled to the amplification feature of stripping voltammetry (to yield femtomole detection limits) and with an efficient magnetic removal of nonhybridized nucleic acids to offer high sensitivity and selectivity. The protocol is illustrated for the simultaneous detection of three DNA sequences related to the BCRA1 breast-cancer gene in a single sample in connection to magnetic beads bearing the corresponding oligonucleotide probes. The new electrochemical coding is expected to bring new capabilities for DNA diagnostics, and for bioanalysis, in general.
描述了基于使用不同无机胶体（量子点）纳米晶体示踪剂同时电化学测量多个DNA靶标的核酸杂交测定法。三种编码纳米颗粒（硫化锌、硫化镉和硫化铅）用于区分三种DNA靶标的信号，并与重金属溶解产物的溶出伏安测量相关联。在汞涂覆的玻碳电极上（相对于Ag/AgCl参比电极），这些产物在-1.12 V（Zn）、-0.68 V（Cd）和-0.53 V（Pb）处产生明确且分辨良好的溶出峰。这些峰的位置和大小反映了相应DNA靶标的身份和水平。多靶标检测能力与溶出伏安法的放大特性（产生飞摩尔检测限）以及有效磁去除未杂交核酸相结合，以提供高灵敏度和选择性。该方案用于在单个样品中同时检测与BCRA1乳腺癌基因相关的三个DNA序列，并与带有相应寡核苷酸探针的磁珠相关联。这种新的电化学编码有望为DNA诊断以及一般的生物分析带来新的能力。
