title: Graphene signal amplification for sensitive and real-time fluorescence anisotropy detection of small molecules.
abstract: Fluorescence anisotropy (FA) is a reliable, sensitive, and robust assay approach for determination of many biological targets. However, it is generally not applicable for the assay of small molecules because their molecular masses are relatively too small to produce observable FA value changes. To address this issue, we report herein the development of a FA signal amplification strategy by employing graphene oxide (GO) as the signal amplifier. Because of the extraordinarily larger volume of GO, the fluorophore exhibits very high polarization when bound to GO. Conversely, low polarization is observed when the fluorophore is dissociated from the GO. As proof-of-principle, the approach was applied to FA detection of adenosine triphosphate (ATP) with a fluorescent aptamer. The aptamer exhibits very high polarization when bound to GO, while the FA is greatly reduced when the aptamer complexes with ATP, which exhibits a maximum signal change of 0.316 and a low detection limit of 100 nM ATP in buffer solution. Successful application of this strategy has been demonstrated that it can be constructed either in a "signal-off" or in a "signal-on" detection scheme. Moreover, because FA is less affected by environmental interferences, FA measurements could be conveniently used to directly detect as low as 1.0 μM adenosine triphosphate (ATP) in human serum. The universality of the approach could be achieved to detect an array of biological analytes when complemented with the use of functional DNA structures.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Liu
authors.forename: Changyao
authors.initials: C
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.forename: Yaping
authors.initials: Y
authors.lastname: Hu
authors.forename: Jishan
authors.initials: J
authors.lastname: Li
authors.forename: Sheng
authors.initials: S
authors.lastname: Yang
authors.forename: Yinhui
authors.initials: Y
authors.lastname: Li
authors.forename: Ronghua
authors.initials: R
authors.lastname: Yang
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
authors.forename: Cheng Zhi
authors.initials: CZ
authors.lastname: Huang
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000097:blood; D003199:Computer Systems; D005454:Fluorescence Polarization / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D006801:Humans
chemical_list: D006108:Graphite; D000255:Adenosine Triphosphate