The Synthesis Of Graphene Nanohybrids And Electrochemical Determination Of Protein And Flavonoids Drugs

Chapter 1:Firstly, the characteristics, application and synthesis methods of graphene were introduced. Secondly, this paper briefly describes the functional graphene, metal nano and cyclodextrins. Thridly, the thrombin, rutin and flavonoids drugs on the significance of the organism and the applications of electrochemical sensor for detecting the drug were presented. Finally, we sum up the research background, main contents and innovative points.Chapter 2:We demonstrate a facile one-pot synthetic strategy for controlled synthesis of thio-(3-cyclodextrin functionalized graphene/gold nanoparticles (SH-(3-CD-Gr/AuNPs) composites using SH-β-CD as both the dispersant and linker. The obtained SH-P-CD-Gr/AuNPs integrate the excellent electrical properties and large surface area of graphene and AuNPs with supramolecular recognition ability of CD, which show more effective electron transfer and higher enriched ability for the ferrocene probe via the host-guest interaction between CD and ferrocene than SH-β-CD-Gr. In the presence of target, the stronger interaction between aptamer and target makes the ferrocene move closer to the electrode surface, thus facilitating the electron transfer. Based on this sensing mechanism, a new and highly sensitive biosensing concept by the use of SH-(3-CD-Gr/AuNPs as enhancing materials is demonstrated for "signal-on" detection of targets (thrombin as a model target). This biosensor exhibits a wide linear range for thrombin from 1.6×10-17 mol·L-1 to 1.6×10-15 mol·L-1 and a very low limit of detection 5.2×10-18 mol·L-1, which is two-order magnitude better than those of SH-P-CD-Gr (the detection linear range from 1.6×10-15 mol·L-1 to 8.0×10-13 mol·L-1 and detection limit of 1.6×10-15 mol·L-1). Our proposed electrochemical aptasensor based on SH-β-CD-Gr/AuNPs shows good selectivity against other proteins such as human serum albumin, lysozyme and insulin. To the best of our knowledge, the present SH-β-CD-Gr/AuNPs hybrids are the most efficient graphene-based electrochemical active probes ever reported for biosensors.Chapter 3:In this work, an ultrasensitive electrochemical sensing platform on account of thio-β-cyclodextrin functionalized graphene/palladium nanoparticles (SH-β-CD-Gr/PdNPs) has been developed to detect rutin and isoquercitrin. The obtained SH-β-CD-Gr/PdNPs were characterized by UV-vis spectroscopy, FTIR spectroscopy, TEM, X-ray photoelectron spectroscopy, and cyclic voltammetry, which confirmed that SH-β-CD/PdNPs had been effectively functionalized on the surface of graphene nanoparticles (GNs). Under optimum conditions, differential pulse voltammetry was utilized measuring the peak currents of two drugs. The linear response ranges for rutin and isoquercitrin are 1.0×10-9-3.0×10-5 mol·L-1 and 5.0×10-12-5.0×10-6 mol·L-1, with the low limit of detection 3.0× 10-10 mol·L-1 and 1.6×10-12 mol·L-1, respectively. The method has good stability arid high sensitivity, which will bring important applications in Chinese medicine or other fields.