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Efficient biorecognition of thrombin (TB), a serine protease with crucial role in physiological and pathological blood coagulation, is a hot topic in medical diagnostics. In this work, we investigate the ability of synthetic thrombin aptamer (TBA), immobilized on a gold substrate, to bind thrombin by two different label-free techniques: the quartz crystal microbalance (QCM) and the spectroscopic ellipsometry (SE). By QCM characterization in the range from 20 to 110 nM, we demonstrate high specificity of TBA-TB interaction and determine affinity constant () of  nM, system sensitivity of  Hz nM−1, and limit of detection (LOD) of  pM. The interaction between TBA and TB is also investigated by SE, an all-optical method, by quantifying the thickness increase of the TBA film assembled on gold substrate. AFM characterization of TBA and TB molecules deposited on flat silicon surface is also supplied.
Publication date: 
1 Jan 2016

Jane Politi, Ilaria Rea, Fabrizia Nici, Principia Dardano, Monica Terracciano, Giorgia Oliviero, Nicola Borbone, Gennaro Piccialli, Luca De Stefano

Biblio References: 
Volume: 2016
Journal of Sensors