title: A convenient sandwich assay of thrombin in biological media using nanoparticle-enhanced fluorescence polarization.
abstract: A new aptamer biosensor was presented for the detection of thrombin in this work, which was based on fluorescence polarization (FP) using silica nanoparticles as enhancement probe. The silica nanoparticles covered by streptavidin were tagged with a thrombin aptamer (5'-biotin-GGTTGGTGTGGTTGG-3'), which was bound to the surface of silica nanoparticle through the specific interaction between streptavidin and biotin. In the presence of thrombin, it induced the aptamer to form quadruplex structure. When the other thrombin aptamer labeled with fluorescein (5'-FAM-AGTCCGTGGTAGGGCAGGTTGGGGTGACT-3') was added to the above system, a sandwich structure can form at the surface of silica nanoparticles. The fluorescence polarization was therefore enhanced and quantification between fluorescence polarization signal and concentration of thrombin was built. The sensor provided a linear range from 0.6 to 100 nM for thrombin with a detection limit of 0.20 nM (3.29 SB/m, according to the recent recommendation of IUPAC) in a homogeneous media. The same linear range was obtained in spiked human serum samples with a slightly higher detection limit (0.26 nM), demonstrating high anti-interference of the sensor in a complex biological sample matrix. And the sensor can be used to monitor spiked concentration of thrombin level in real human plasma with satisfactory results obtained.
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China. Electronic address: yueqiaoli@gmail.com.
authors: Qiaoli
authors: Q
authors: Yue
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Tongfei
authors: T
authors: Shen
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Lei
authors: L
authors: Wang
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Shuling
authors: S
authors: Xu
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Haibo
authors: H
authors: Li
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Qingwang
authors: Q
authors: Xue
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China.
authors: Yuanfu
authors: Y
authors: Zhang
authors: Shandong Provincial Key Lab of Test Technology on Food Quality and Safety, Shandong Academy of Agricultural Sciences, Jinan 250100, PR China.
authors: Xiaohong
authors: X
authors: Gu
authors: Shandong Provincial Key Lab of Test Technology on Food Quality and Safety, Shandong Academy of Agricultural Sciences, Jinan 250100, PR China.
authors: Shuqiu
authors: S
authors: Zhang
authors: Department of Chemistry, Liaocheng University, Liaocheng 252059, PR China. Electronic address: liujifeng111@gmail.com.
authors: Jifeng
authors: J
authors: Liu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods; D019793:Fluorescein / Q000737:chemistry; D005454:Fluorescence Polarization / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D005456:Fluorescent Dyes; C081676:thrombin aptamer; D012822:Silicon Dioxide; D013917:Thrombin; D019793:Fluorescein
keywords: Aptamer; Fluorescence polarization; Plasma; Silica nanoparticle; Thrombin