Ru(bpy)32+ Electrochemiluminescence Sensors based on Polyvinylalcohol-Silica Nanofiber Mat

Abstract

A nanofiber mat-modified sensing electrode was studied to develop a stable and sensitive solid-state electrochemiluminescence (ECL) sensor. For this purpose, Ru(bpy)32+-doped silica nanoparticles (Ru@SiO2) were first synthesized for the strong immobilization of Ru(bpy)32+ luminophores via sol-gel route, and then organic-inorganic hybrid nanofibers were collected on a patterned ITO electrode for the formation of a sensing layer with a great surface area by electrospinning a solution of polyvinylalcohol (PVA) and Ru@SiO2. Material properties of the electrospun Ru@SiO2-PVA nanofiber mat were characterized through various analysis methods including SEM, FT-IR, EDX, XRD and XPS. These results demonstrated the successful formation of Ru@SiO2-PVA hybrid nanofibers with an average diameter of ca. 600 nm and smooth surface morphology. Furthermore, the hybrid mat exhibited a high stability in wet solution due to the strong Ru(bpy)32+ immobilization and the Si-O-C bond formation between SiO2 and PVA components. Cyclic voltammograms of the hybrid mat-modified electrode displayed quasi-reversible redox characteristics of the immobilized active Ru(bpy)32+ centers in a PBS solution. The Ru@SiO2-PVA nanofiber-modified electrode demonstrated excellent hydro-stability and sensitive ECL emission in the detection of tripropylamine (TPA). The ECL intensity was found to increase gradually as increasing a TPA concentration from 10 mM to 10 nM.