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).