Nanogravimetric and optical characterizations of thrombin interaction with a self-assembled thiolated aptamer

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 (kd) of 17.7 ± 0.3 nm,system sensitivity of 0.42 ± 0.03 hz nm-1,and limit of detection (lod) of 240 ± 20 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. © 2016 jane politi et al.