Institute of Bioengineering and Nanotechnology, Singapore.
Biosens Bioelectron. 2010 Feb 15;25(6):1420-6. doi: 10.1016/j.bios.2009.10.041. Epub 2009 Nov 5.
An ultrasensitive electrochemical biosensor is demonstrated for the detection of a synthetic single-stranded DNA (ss-DNA) with a detection limit down to femtomolar levels. The synthetic ss-DNA with sequence associated with the influenza A virus RNA was used as our model target DNA. The detection scheme was based on a sandwich structure involving a capture probe, the target DNA and a detection probe. An avidin-labeled glucose oxidase (GOx) was attached to a biotinylated detection probe via biotin-avidin interaction. Subsequently, the DNA hybridization event was transduced and amplified by an in-situ enzyme-catalyzed deposition of cupric hexacyanoferrate (CuHCF) nanoparticles in the presence of glucose, cupric ions and ferricyanide. The peak current in differential pulse voltammetry of the deposited CuHCF nanoparticles directly correlated to the concentration of the target DNA. DNA was therefore quantified in the concentration range from 1.0 fM to 10 pM with a detection limit of 1.0 fM and a relative standard derivation of <or=11% at 100 fM. Excellent mismatch discrimination was demonstrated in the proposed biosensor.
一种超灵敏电化学生物传感器被开发用于检测一种合成的单链 DNA（ss-DNA），其检测限低至飞摩尔水平。具有与甲型流感病毒 RNA 相关序列的合成 ss-DNA 被用作我们的模型靶 DNA。检测方案基于三明治结构，包括捕获探针、靶 DNA 和检测探针。通过生物素-亲和素相互作用将辣根过氧化物酶（GOx）标记的亲和素连接到生物素化的检测探针上。随后，在葡萄糖、铜离子和铁氰化物存在下，通过原位酶催化沉积铜六氰合铁酸盐（CuHCF）纳米颗粒，将 DNA 杂交事件进行转导和放大。沉积的 CuHCF 纳米颗粒的差分脉冲伏安法中的峰值电流与靶 DNA 的浓度直接相关。因此，DNA 的定量范围从 1.0 fM 到 10 pM，检测限为 1.0 fM，在 100 fM 时相对标准偏差<或=11%。在提出的生物传感器中证明了出色的错配识别能力。
