关键词: 核酸适配体, 凝血酶, 磁珠, 比色分析

Abstract:

Choosing nucleic acid aptamers as a high efficient and special recognition/sensing element, we developed a novel colorimetric assay based on magnetically separation and special capture to achieve the goal of capturing/tracing target protein. Two different aptamers simply biotinylated, which bound the thrombin in different sites with high affinity, were chosen to develop a sandwich assay. The protein was captured by aptamer-functionalized magnetic beads and detected after the addition of the second biotinylated aptamer and of streptavidin labeled with an enzyme, and the detection of the product generated by enzymatic reaction was achieved by colorimetric assay. This magnetic beads based enzyme linked aptamer assay was capable of capturing thrombin with high specificity, didn′t be affected by other interfering proteins in complex matrix such as human serum albumin and bovine hemoglobin. The detection of thrombin in serum could be carried out with naked eyes, without the need of expensive analytical instruments and more assay time. A linear range from 10 to 80 nmol/L is obtained with a detection limit of 10 nmol/L for thrombin.

Key words: Aptamer, Thrombin, Magnetic bead, Colorimetric