Highly selective resonance scattering detection of trace thrombin using aptamer-modified AuRe nanoprobe

The gold-rhenium (AuRe) composite nanoparticle was prepared by NaBH4 reduction procedure, and was modified by the aptamer to obtain an AuRe nanoprobe (AuRessDNA) for thrombin. In pH 7.0 Tris-HCl buffer solution and in the presence of salt, the nanoprobe specifically combined with thrombin to form AuRe-aptamer-thrombin cluster that resulted in the resonance scattering intensity (I (560 nm)) increasing at 560 nm. The increased intensity Delta I (560 nm) was linear to the thrombin concentration in the range of 0.115-6.93 nmol/L, with a regression equation of Delta I (560 nm) = 53.0 C + 2.5, a correlation coefficient of 0.9989, and a detection limit of 13 pmol/L. This method was applied to detect thrombin in human plasma samples, with satisfactory results.