title: A new signal-on photoelectrochemical biosensor based on a graphene/quantum-dot nanocomposite amplified by the dual-quenched effect of bipyridinium relay and AuNPs.
abstract: A new photoelectrochemical (PEC) biosensor was developed by using carboxyl-functionalized graphene and CdSe nanoparticles. This sensitive interface was then successfully applied to detection of thrombin based on the dual-quenched effect of PEC nanoparticle, which relied on the electron transfer of a bipyridinium relay and energy transfer of AuNPs. After recognition with an aptamer, the PEC nanoparticle was removed and a signal-on PEC biosensor was obtained. Moreover, the bio-barcode technique used in the preparation of PEC nanoparticle could avoid cross-reaction and enhances the sensitivity. Taking advantages of the various methods mentioned above, the sensitivity could be easily enhanced. In addition, in this work we also investigated graphene that was modified with different functional groups and AuNPs of different particle sizes. Under optimal conditions, a detection limit of 5.9×10(-15)  M was achieved. With its simplicity, selectivity, and sensitivity, this strategy shows great promise for the fabrication of highly efficient PEC biosensors.
authors.affiliation: Key Laboratory of Biochemical Analysis, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
authors.forename: Xiaoru
authors.initials: X
authors.lastname: Zhang
authors.forename: Yunpeng
authors.initials: Y
authors.lastname: Xu
authors.forename: Yanqiang
authors.initials: Y
authors.lastname: Yang
authors.forename: Xia
authors.initials: X
authors.lastname: Jin
authors.forename: Sujuan
authors.initials: S
authors.lastname: Ye
authors.forename: Shusheng
authors.initials: S
authors.lastname: Zhang
authors.forename: Lilin
authors.initials: L
authors.lastname: Jiang
mesh_terms: D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D010316:Particle Size; D045663:Quantum Dots
chemical_list: D006046:Gold; D006108:Graphite