Bipolar silica nanochannel array for dual-mode electrochemiluminescence and electrochemical immunosensing platform

Herein we reported the construction of dual-mode electrochemiluminescence (ECL) and electrochemical (EC) sensing platform using the bipolar silica nanochannel array (bp-SNA) confined with the bifunctional probe (tris(2,2′-bipyridyl) ruthenium , Ru(bpy) 3 2+ ) inside the nanochannels (designated as Ru@bp-SNA). With the asymmetric surface charges, bp-SNA on the indium tin oxide electrode can effectively function as electrostatic nanocage for the stable confinement of Ru(bpy) 3 2+ via dual electrostatic force , namely electrostatic attraction of inner negative surface and electrostatic repulsion of outer positive surface. Ru(bpy) 3 2+ immobilized into the nanospace acts as both highly efficient ECL luminophore and well-defined EC redox molecule to generate strong signal. Since the modification of bio-recognition units on the top of Ru@bp-SNA is able to confer excellent recognitive capacity and obtain the formation of complex in the presence of specific analyte, the decrease of ECL and EC signals enables the quantitative detection of this analyte. As proof-of-concept experiments, two tumor related biomarkers, CEA and CA15–3, have been successfully determined in aqueous solution and human serum by ECL and EC modes, respectively.