State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
Anal Chem. 2009 Dec 15;81(24):9972-8. doi: 10.1021/ac901727z.
In this paper, a bifunctional electrochemical biosensor for highly sensitive detection of small molecule (adenosine) or protein (lysozyme) was developed. Two aptamer units for adenosine and lysozyme were immobilized on the gold electrode by the formation of DNA/DNA duplex. The detection of adenosine or lysozyme could be carried out by virtue of switching structures of aptamers from DNA/DNA duplex to DNA/target complex. The change of the interfacial feature of the electrode was characterized by cyclic voltammertic (CV) response of surface-bound Ru(NH(3))(6). On the other hand, DNA functionalized Au nanoparticles (DNA-AuNPs) were used to enhance the sensitivity of the aptasensor because DNA-AuNPs modified interface could load more Ru(NH(3))(6) cations. Thus, the assembly of two aptamer-contained DNA strands integrated with the DNA-AuNPs amplification not only improves the sensitivity of the electrochemical aptasensor but also presents a simple and general model for bifunctional aptasensor. The proposed aptasensor has low detection limit (0.02 nM for adenosine and 0.01 microg mL(-1) for lysozyme) and exhibits several advantages such as high sensitivity and bifunctional recognition.
本文构建了一种用于小分子（腺苷）或蛋白质（溶菌酶）高灵敏检测的电化学生物传感器。利用 DNA/DNA 双链结构将两种适体单元固定在金电极表面，实现了适体从 DNA/DNA 双链到 DNA/目标复合物的构象转换。通过表面结合的 Ru(NH3)6的循环伏安响应（CV），可以对电极界面的变化进行特征描述。另一方面，采用 DNA 功能化金纳米粒子（DNA-AuNPs）提高适体传感器的灵敏度，因为 DNA-AuNPs 修饰的界面可以负载更多的 Ru(NH3)6阳离子。因此，两个包含适体的 DNA 链的组装与 DNA-AuNPs 的放大集成不仅提高了电化学生物适体传感器的灵敏度，而且为双功能适体传感器提供了一个简单而通用的模型。该适体传感器具有较低的检测限（腺苷为 0.02 nM，溶菌酶为 0.01 μg mL(-1)），并表现出高灵敏度和双功能识别等优点。
