Wang Joseph, Liu Guodong, Zhu Qiyu
Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, 88003, USA.
Anal Chem. 2003 Nov 15;75(22):6218-22. doi: 10.1021/ac034730b.
The preparation and advantages of indium microrod tracers for solid-state electrochemical detection of DNA hybridization are described. The cylindrical metal particles were prepared by a template-directed electrochemical synthetic route involving plating of indium into the pores of a host membrane. The linear relationship between the charge passed during the preparation and the resulting particle size allows tailoring of the sensitivity of the electrical DNA assay. The resulting micrometer-long rods thus offer a greatly lower detection limit (250 zmol), as compared to common bioassays' spherical nanoparticle tags. Indium offers a very attractive electrochemical stripping behavior and is not normally present in biological samples or reagents. Solid-state derivative-chronopotentiometric measurements of the indium tracer have been realized through a "magnetic" collection of the DNA-linked particle assembly onto a thick-film electrode transducer. Factors affecting the performance, including the preparation of the microrods and pretreatment of the transducer surface, were evaluated and optimized. The resulting protocol offers great promise for other affinity bioassays, as well as for electrical coding and identification (through the plating of different metal markers and of multimetal redox-encoded tags).
本文描述了用于DNA杂交固态电化学检测的铟微棒示踪剂的制备方法及其优势。通过模板导向的电化学合成路线制备圆柱形金属颗粒，该路线包括将铟镀入主膜的孔中。制备过程中通过的电荷与所得颗粒尺寸之间的线性关系使得能够调整DNA电化学检测的灵敏度。与常见生物检测中的球形纳米颗粒标签相比，所得的微米长棒具有大大降低的检测限（250 zmol）。铟具有非常吸引人的电化学溶出行为，并且通常不存在于生物样品或试剂中。通过将与DNA相连的颗粒组件“磁性”收集到厚膜电极换能器上，实现了铟示踪剂的固态导数计时电位测量。评估并优化了影响性能的因素，包括微棒的制备和换能器表面的预处理。所得方案对于其他亲和生物检测以及电编码和识别（通过镀不同的金属标记物和多金属氧化还原编码标签）具有很大的前景。
