| 摘要 |
A universal detection system based on allosteric aptamers, signal amplification cascade, and eye-detectable phrase transition. A broadly applicable homogeneous detection system is provided. It utilizes components of the blood coagulation cascade in the presence of polystyrene microspheres (MS) as a signal amplifier. Russell's viper venom factor X activator (RVV-X) triggers the cascade, which results in an eye-visible phase transition-precipitation of MS bound to clotted fibrin. An allosteric RNA aptamer, RNA132, with affinity for RVV-X and human vascular endothelial growth factor (VEGF<SUB>165</SUB>) was created. RNA132 inhibits enzymatic activity of RVV-X. The effector molecule, VEGF<SUB>165</SUB>, reverses the inhibitory activity of RNA132 on RVV-X and restores its enzymatic activity, thus triggering the cascade and enabling the phase transition. Similar results were obtained for another allosteric aptamer modulated by a protein tyrosine phosphatase. The assay is instrumentation-free for both processing and readout.
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