A self-enhanced electrochemiluminescence immunosensor based on L-Lys-Ru(dcbpy)3(2+) functionalized porous six arrises column nanorods for detection of CA15-3.

In this work, a new manganese ions doped zinc oxide porous six arrises column nanorods was rapidly synthesized with L-Lys as the precipitating and capping agent (L-Lys/Mn-ZnONRs). The as-synthesized L-Lys/Mn-ZnONRs exhibited large specific surface area and high ferromagnetism, which could serve as excellent nanocarrier. Meanwhile, due to the outstanding conductivity and biocompatibility, platinum nanoparticles (PtNPs) were decorated on the surface of L-Lys/Mn-ZnONRs by Pt-N bond to form PtNPs/L-Lys/Mn-ZnONRs complexes. After that, the obtained complexes were used to immobilize abundant tris (4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)3(2+)) and detection antibody for construction of sandwiched electrochemiluminescence (ECL) immunosensor. Coincidentally, L-Lys not only acted as the precipitating and capping agent to control shape and size of L-Lys/Mn-ZnONRs, but also acted as a co-reactant of Ru(dcbpy)3(2+) to efficiently amplify the ECL signal. Importantly, L-Lys had free amino group which could link with Ru(dcbpy)3(2+)via amide bond to form a self-enhanced ECL complex. Through this way, the electron transfer path between luminophore and co-reactant reagent was shortened and the energy loss of luminophore was lessened. Consequently, the prepared ECL immunosensor showed excellent performance for the detection of carbohydrate antigen 15-3 in the range from 0.05 U/mL to 120 U/mL with a detection limit of 0.014 U/mL (S/N=3) and a correlation coefficient of R=0.9977. Moreover, the prepared ECL immunosensor had good stability, excellent selectivity and satisfactory reproducibility.