Resonance light scattering (RLS) is a sensitive technique for monitoring scattered light induced by extended aggregates of chromophores. It has been widely used to study aggregations for its simple manipulation, high sensitivity and great versatility. Gold nanoparticles generate colorful light-scattering signals due to their unique surface plasmon resonances, hence extraordinary light scattering upon aggregation. In this paper we report a rapid and sensitive method based on gold nanoparticles and DNA aptamer to detect protein biomarkers by RLS. Thiol modified thrombin aptamer was covalently assembled to the surface of gold nanoparticles as nanobio probes. As thrombin has two specific binding sites for its aptamer, it can bridge the well dispersed nanoparticles and lead to a network of particle aggregations. The formation of aggregation ia measured by RLS, and the specific detection of thrombin at nM level is achieved. The method has good specificity.
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