Gao Li, Li Qin, Deng Zebin, Brady Brendan, Xia Ni, Zhou Yang, Shi Haixia
Institute of Life Sciences, Jiangsu University, Zhenjiang.
Department of Physics, University of Victoria, Victoria, BC, Canada.
Int J Nanomedicine. 2017 Oct 25;12:7847-7853. doi: 10.2147/IJN.S145585. eCollection 2017.
Molybdenum disulfide (MoS) has shown highly attractive superiority as a platform for sensing. However, DNA physisorption on the surface of MoS was susceptible to nonspecific probe displacement and false-positive signals. To solve these problems, we have developed a novel MoS-aptamer nanosheet biosensor for detecting thrombin using a covalently linked aptamer to the MoS nanosheet. Ten percent Tween 80 was used to prevent thrombin from nonspecific binding and to rapidly form thiol-DNA/gold nanoparticle (AuNP) conjugates. Furthermore, an MoS and exonuclease coassisted signal amplification strategy was developed to improve the detection limit for thrombin. We used the hybridization of the aptamer molecules and the matched strand with a 5' terminal thiol to immobilize the aptamer molecules on the surface of AuNPs in AuNPs@MoS nanocomposites. Exonuclease digested the single-strand aptamer and released the thrombin, which was then detected in the next recycle. With the coassisted amplification strategy, a 6 fM detection limit was achieved, showing that this method has higher sensitivity than most reported methods for thrombin detection. The results presented in this work show that this method of covalently attaching the aptamer and using the coassisted amplification is a promising technique for the detection of protein in medical diagnostics.
二硫化钼（MoS）作为一种传感平台已展现出极具吸引力的优势。然而，DNA在MoS表面的物理吸附易受非特异性探针置换和假阳性信号的影响。为解决这些问题，我们开发了一种新型的MoS适配体纳米片生物传感器，用于使用与MoS纳米片共价连接的适配体来检测凝血酶。使用10%的吐温80来防止凝血酶的非特异性结合，并快速形成硫醇-DNA/金纳米颗粒（AuNP）缀合物。此外，还开发了一种MoS与核酸外切酶协同的信号放大策略，以提高凝血酶的检测限。我们利用适配体分子与带有5'末端硫醇的匹配链的杂交，将适配体分子固定在AuNPs@MoS纳米复合材料中AuNP的表面。核酸外切酶消化单链适配体并释放凝血酶，然后在下次循环中进行检测。通过协同放大策略，实现了6 fM的检测限，表明该方法比大多数已报道的凝血酶检测方法具有更高的灵敏度。这项工作的结果表明，这种将适配体共价连接并使用协同放大的方法是医学诊断中蛋白质检测的一种有前景的技术。
