Ultrasensitive electrochemiluminescence immunosensor based on Ru(bpy)32+ and Ag nanoparticles doped SBA-15 for detection of cancer antigen 15-3

A label-free electrochemiluminescence (ECL) immunosensor based on functionalized Santa Barbara Amorphous-15 (SBA-15) has been developed for detection of cancer antigen 15-3 (CA15-3). The functionalized SBA-15 was prepared by decoration of citrate-capped Ag nanoparticles and incorporation of Ru(bpy)32+on SBA-15. The Ag nanoparticles show remarkable enhancement effect on ECL properties of Ru(bpy)32+. In order to incorporate more Ru(bpy)32+, anionic surfactant sodium dodecyl sulfate (SDS) was used to increase the negative charge of the composite matrix. Chitosan–ionic liquid (CHIT–IL) were also used to increase the conductivity and film stability. The functionalized SBA-15 was used to label the anti-CA15-3 based on the covalent interaction between Ag nanoparticles and the amines of anti-CA15-3. The ECL immunosensor that used to detect breast cancer biomarker CA15-3 exhibits high ECL intensity, good biocompatibility and long-term stability. The results show that the ECL immunosensor has high sensitivity for CA15-3 with a linear range from 0.01 U/mL to 100 U/mL and a detection limit of 0.004 U/mL (S/N = 3).