A sensitive electrochemical aptasensor based on palladium nanoparticles decorated graphene–molybdenum disulfide flower-like nanocomposites and enzymatic signal amplification

• Published in: Analytica chimica acta 2015-01, Vol.853, p.234-241
• Main Authors: Jing, Pei, Yi, Huayu, Xue, Shuyan, Chai, Yaqin, Yuan, Ruo, Xu, Wenju
• Format: Article
• Language: English
• Subjects: Aptamers, Nucleotide - chemistry; Aptasensor; Disulfides - chemistry; Electrochemical response; Electrochemical Techniques; Electrodes; G-Quadruplexes; Glucose Oxidase - chemistry; Glucose Oxidase - metabolism; Graphene–molybdenum disulfide; Graphite - chemistry; Hemin - chemistry; Hydrogen Peroxide - chemistry; Metal Nanoparticles - chemistry; Molybdenum - chemistry; Nanocomposites - chemistry; Oxidation-Reduction; Palladium - chemistry; Signal amplification; Thrombin; Thrombin - analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2014.10.003

[Display omitted] •PDDA–G–MoS2 nanoflowers were firstly used for the fabrication of thrombin aptasensor.•MoS2 was adopted to enhance the surface area of graphene and accelerate the electron transfer.•GOD, PdNPs and hemin/G-quadruplex could amplify the electrochemical signal through synergetic catalysis.•The proposed aptasensor displayed an improved sensitivity. In the present study, with the aggregated advantages of graphene and molybdenum disulfide (MoS2), we prepared poly(diallyldimethylammonium chloride)–graphene/molybdenum disulfide (PDDA–G–MoS2) nanocomposites with flower-like structure, large surface area and excellent conductivity. Furthermore, an advanced sandwich-type electrochemical assay for sensitive detection of thrombin (TB) was fabricated using palladium nanoparticles decorated PDDA–G–MoS2 (PdNPs/PDDA–G–MoS2) as nanocarriers, which were functionalized by hemin/G-quadruplex, glucose oxidase (GOD), and toluidine blue (Tb) as redox probes. The signal amplification strategy was achieved as follows: Firstly, the immobilized GOD could effectively catalyze the oxidation of glucose to gluconolactone, coupling with the reduction of the dissolved oxygen to H2O2. Then, both PdNPs and hemin/G-quadruplex acting as hydrogen peroxide (HRP)-mimicking enzyme could further catalyze the reduction of H2O2, resulting in significant electrochemical signal amplification. So the proposed aptasensor showed high sensitivity with a wide dynamic linear range of 0.0001 to 40nM and a relatively low detection limit of 0.062pM for TB determination. The strategy showed huge potential of application in protein detection and disease diagnosis.