Metallic Inverse Opals: An Electrochemiluminescence enhanced Substrate for Sensitive Bioanalysis

Here, we proposed a novel local surface plasmon resonance (LSPR) enhanced ECL strategy based on the metallic inverse opals and Ru(bpy)₃²⁺-doped silica nanoparticles (RuSi NPs). Gold inverse opals (GIOs), as a plasmonic array, could interact with the ECL of RuSi NPs and excite the electromagnetic (EM) field at the gold surface. The triggered EM field could enhance the ECL emission of RuSi NPs. We compared the electrochemical and ECL performances of RuSi NPs modified on the gold electrodes with different surface morphologies and found that the ECL emission of RuSi NPs patterned at the inner surface of GIOs exhibited the highest intensity. The finite-difference time-domain (FDTD) simulations indicated that the EM field was related to the surface morphology of the metallic nanostructure, and the highest EM field was observed at the inner surface of the GIOs. Because of the superior ECL performances, the inner surfaces of GIOs were developed for nucleic acid detection with a detection limit of 3.3 fM (S/N = 3), which shows great promise for bioanalysis.