An electrochemiluminescence aptasensor based on Ru(bpy)32+ encapsulated titanium-MIL-125 metal-organic framework for bisphenol A assay

Ultrasensitive and selective determination of bisphenol A (BPA) was achieved by a solid-state electrochemiluminescence (ECL) aptasensor. The Ti-based MOFs (MIL-125, MIL stands for Materials of Institute Lavoisier) have porous structure and large specific surface area. They were used as a carrier for Ru(bpy)(3)(2+) by a hydrothermal synthesis method. The Ru(bpy)(3)(2+) encapsulated MIL-125 (Ru(bpy)(3)(2+)@MIL-125) was dropped on a glass carbon electrode (GCE) and used as working electrode. After that, the thiol-based aptamer of BPA was used to modify the working electrode by Ti-S bond. As a result of the specific binding affinity between aptamer and BPA, the ECL signal was significantly quenched. Thus, a selective electrochemiluminescence (ECL) aptasensor for BPA was developed. The ECL aptasensor based on Ru(bpy)(3)(2+)@MIL-125 has a good ECL response toward detecting BPA. Under optimal conditions, the aptasensor can detect BPA in a wide linear range from 1.0 x 10(-12) to 1.0 x 10(-6) M with an excellent determination limit of 6.1 x 10(-13) M (S/N = 3). The ECL aptasensor can selectively detect BPA in a mixture containing BPA interference compounds.