基于“树枝状”信号放大的电化学DNA生物传感器研究

An electrochemical biosensor for DNA amplified detection based on dendritic DNA-capped gold nanoparticles

发展了一种基于"树枝状"信号放大的电化学生物传感器用于DNA的检测。该传感器利用两种DNA功能化的纳米金颗粒,通过两次"三明治"杂交,在电极表面形成"树枝"状结构,从而实现DNA的定量检测。首先通过共价交联方法获得巯基DNA1和DNA2修饰的两种纳米金颗粒,其中DNA1和DNA2与目标cDNA部分互补。然后,修饰在金电极上的捕获探针DNA1与目标cDNA分子及巯基DNA2修饰的纳米金颗粒(DNA2-AuNPs)形成第一个"三明治"杂交结构,实现一次放大检测。接着,DNA2-AuNPs又可与cDNA、巯基DNA1修饰的纳米金颗粒(DNA1-AuNPs)形成第二个"三明治"杂交结构,实现二次放大检测。这种"树枝状"放大信号的方法的检测限是0.13pmol/L,相对仅利用纳米金颗粒放大的方法而言,其检测限降低了4倍。并且,该传感器具有较好的识别碱基错配的能力。

We herein developed a dendritic signal amplification biosensor for DNA detection. It relied on the use of two different DNA functionalized gold particles, which could be self-assembled to build sandwich-type dendritic architectures. The two different gold particles were modified by DNA1 or DNA2, DNA1 and DNA2 were partly matched with cDNA. The first ＂sandwich＂ involved capture probe DNA1 immobilized on gold electrodes and DNA2 labeled with gold nanoparticles that flank the target eDNA sequence. The dendritic amplification was based on the second ＂sandwich＂, which DNA2 labeled with gold nanoparticles and DNA1 labeled with gold nanoparticles that flank the target eDNA sequence. The detection limit was 0.13 pmol/L. The strategy has improved the detection limit for nearly 4 times compared to ＂gold nanoparticle-only＂ method. In addition, the sensor exhibited excellent selectivity against single-base mutation discrimination.