期刊
SENSORS
卷 19, 期 20, 页码 -出版社
MDPI
DOI: 10.3390/s19204424
关键词
thrombin detection; fluorescence; aptamer; N-methyl-mesoporphyrin IX (NMM)
资金
- National Natural Science Foundation of China [61572302, 61272246]
- Shaanxi Normal University Graduate Innovation Fund Project
- Fundamental Research Funds for the Central Universities [2018CSLY018]
An enzyme- and label-free aptamer-based assay is described for the determination of thrombin. A DNA strand (S) consisting of two parts was designed, where the first (Sa) is the thrombin-binding aptamer and the second (Se) is a G-quadruplex. In the absence of thrombin, Sa is readily adsorbed by graphene oxide (GO), which has a preference for ss-DNA rather than for ds-DNA. Upon the addition of the N-methyl-mesoporphyrin IX (NMM), its fluorescence (with excitation/emission at 399/610 nm) is quenched by GO. In contrast, in the presence of thrombin, the aptamer will bind thrombin, and thus, be separated from GO. As a result, fluorescence will be enhanced. The increase is linear in the 0.37 nM to 50 mu M thrombin concentration range, and the detection limit is 0.37 nM. The method is highly selective over other proteins, cost-effective, and simple. In our perception, it represents a universal detection scheme that may be applied to other targets according to the proper choice of the aptamer sequence and formation of a suitable aptamer-target pair.
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