An electrochemical sensor based on SiO 2 @TiO 2 -embedded molecularly imprinted polymers for selective and sensitive determination of theophylline

The present work is focused on a typical core-shell-structured SiO2@TiO2-based imprinted polymer composite, employed as a molecular recognition and sensing interface in the construction of an innovative electrochemical sensor. Herein, the methacrylic acid and a bronchodilator drug, theophylline, were used as functional monomer and template, respectively. The SiO2@TiO2 served as a potential signal transducer to shuttle electrons between the binding sites and the electrode. Such modification induced an electrocatalytic effect and thereby greatly improved the electrode kinetics. The analytical features of the developed theophylline sensor have been accessed, and the results have indicated that an increase of differential pulse voltammetric current as compared to the corresponding traditional imprinted polymer modified electrode. Moreover, the sensor has showed high sensitivity, wider linear range (0.01–40 μM), lower detection limit (1.2 nM), and satisfactory long-term stability, which was validated with the complex matrices of tea, human blood serum, and urine, without any matrix effect and cross-reactivity.