Vertically Ordered Silica Mesochannel Modified Bipolar Electrode for Electrochemiluminescence Imaging Analysis

Graphical Enhanced and antifouling bipolar ECL analysis : An indium tin oxide bipolar electrode modified by vertical silica mesochannels (SMCs) is prepared for ECL imaging analysis. The SMCs offer not only a significant enhancement effect on the Ru(bpy) 3 2+ ECL intensity but also the molecular sieving ability against surface biofouling. The sensor can be used for sensitive ECL analysis in real media, such as human blood serum. This paper describes a miniaturized bipolar electrode (BPE) sensor that is constructed with an indium tin oxide (ITO) microband and a slice of poly(dimethylsioxane) (PDMS). The ITO microband modified by vertically ordered silica mesochannels (SMCs) functions as the BPE. Owing to the uniform pore size of ≈2–3 nm in diameter and negatively charged surface, the SMCs can significantly accelerate the mass transport of positively charged species via strong electrostatic interactions. Thus, an increase of more than two orders of magnitude in sensitivity for tri- n -propylamine (TPrA) analysis was achieved for the electrochemluminescence (ECL) of tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy) 3 2+ ) at a relatively low concentration (10 μ m ). Moreover, the SMC film with ultrasmall channels can effectively serve as an antifouling layer of the underlying ITO electrode to prevent the access of undesired large molecules, allowing the electrochemical detection in real complex media, such as atropine and l -proline in human blood serum.