Chemiluminescence assay for the glycoprotein tenascin-C based on aptamer-modified carboxylated magnetic carbon nanoparticles

We report on a method for chemiluminescence (CL) determination of the glycoprotein tenascin-C. Carboxylated carbon nanoparticles (cCNPs) were prepared from activated carbon. Next, the cCNPs were conjugated to magnetic beads (MBs) with a diameter of ∼1 μm by linking its carboxy groups to the amino groups of the MBs. The assay involves the following steps: (a) An aptamer labeled with the CL reagent N-(4-aminobutyl)-N-ethylisoluminol (ABEI) (the labeled aptamer) was adsorbed onto the surface of the carboxy-modified magnetic carbon nanoparticles to form labeled aptamer modified cCNPs-MBs. (b) On addition of sample tenascin-C, it will interact with the labeled aptamer to form a complex with the labeled aptamer. (c) This tenascin-aptamer complex is then dissociated from the surface of the particles and detected by CL whose intensity is linearly related to the concentration of tenascin-C in the 1 pM to 1 nM range. The detection limit is as low as 0.4 pM, and the RSD is 4.2 % at a 50 pM level (for n = 7). The method has been successfully applied to the determination of tenascin-C in human serum samples and holds promise as a widely applicable general platform for aptamer-based CL detection of proteins. (author)