Fabrication of molecularly imprinted polypyrrole /Ru@ethyl-SiO2 nanocomposite for the ultrasensitive electrochemiluminescence sensing of 17β-Estradiol

A solid-state electrochemiluminescence (ECL) sensor for the highly selective and sensitive detection of 17β-estradiol (E2) is presented. The sensor is constructed with Ru(bpy) 3 2+ doped vinyl-SiO 2 nanoparticles (Ru@ethyl-SiO 2 ) and E2 imprinted polypyrrole (MIP). The Ru@ethyl-SiO 2 nanoparticles act as luminophores, while the MIP provides recognition sites for E2. As the adsorbed template molecules can act as co-reactant for Ru@ethyl-SiO 2 , the ECL intensity increases with the adsorption amount of E2 rising, which depends on its concentration in the solution. Owing to the well combination/or synergy of the smart MIP and the high-effective ECL material, the resulting sensor exhibits highly selective and ultrasensitive response to E2. Under the selected conditions, the ECL intensity increment (Δ I ) is linear to the logarithm of E2 concentration over the range from 0.01 to 100 pg mL −1 , and the detection limit is down to 0.005 pg mL −1 (S/N = 3). The ECL sensor also shows good reproducibility and repeatability. It has been successfully applied to the detection of E2 in tea and oral solution samples and the recoveries are 87.7%–115.3%.