The Institute of Chemistry, The Minerva Center for Biohybrid Complex Systems, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
Small. 2014 Jul 23;10(14):2883-91. doi: 10.1002/smll.201400002. Epub 2014 Apr 2.
L-cysteine induces the aggregation of Au nanoparticles (NPs), resulting in a color transition from red to blue due to interparticle plasmonic coupling in the aggregated structure. The hemin/G-quadruplex horseradish peroxidase-mimicking DNAzyme catalyzes the aerobic oxidation of L-cysteine to cystine, a process that inhibits the aggregation of the NPs. The degree of inhibition of the aggregation process is controlled by the concentration of the DNAzyme in the system. These functions are implemented to develop sensing platforms for the detection of a target DNA, for the analysis of aptamer-substrate complexes, and for the analysis of L-cysteine in human urine samples. A hairpin DNA structure that includes a recognition site for the DNA analyte and a caged G-quadruplex sequence, is opened in the presence of the target DNA. The resulting self-assembled hemin/G-quadruplex acts as catalyst that controls the aggregation of the Au NPs. Also, the thrombin-binding aptamer folds into a G-quadruplex nanostructure upon binding to thrombin. The association of hemin to the resulting G-quadruplex aptamer-thrombin complex leads to a catalytic label that controls the L-cysteine-mediated aggregation of the Au NPs. The hemin/G-qaudruplex-controlled aggregation of Au NPs process is further implemented for visual and spectroscopic detection of L-cysteine concentration in urine samples.
L-半胱氨酸诱导金纳米粒子（NPs）聚集，由于聚集结构中的粒子间等离子体耦合，导致颜色从红色转变为蓝色。血红素/G-四链体辣根过氧化物酶模拟 DNA 酶催化 L-半胱氨酸有氧氧化为胱氨酸，这一过程抑制了 NPs 的聚集。该 NPs 聚集过程的抑制程度受体系中 DNA 酶浓度的控制。这些功能被用于开发用于检测靶 DNA 的传感平台，用于分析适体-底物复合物，以及用于分析人尿液样品中的 L-半胱氨酸。发夹 DNA 结构包含用于 DNA 分析物的识别位点和笼状 G-四链体序列，在存在靶 DNA 的情况下打开。所得的自组装血红素/G-四链体作为催化剂控制 Au NPs 的聚集。此外，凝血酶结合适体在与凝血酶结合时折叠成 G-四链体纳米结构。血红素与形成的 G-四链体适体-凝血酶复合物的结合导致控制 Au NPs 由 L-半胱氨酸介导的聚集的催化标记。血红素/G-四链体控制的 Au NPs 聚集过程进一步用于可视化和光谱检测尿液样品中的 L-半胱氨酸浓度。
