Perovskite-type calcium titanate nanoparticles as novel matrix for designing sensitive electrochemical biosensing

In this work, novel perovskite-type calcium titanate nanoparticles (CaTiO3NPs) were for the first time exploited for the immobilization of proteins and the development of electrochemical biosensor. The CaTiO3NPs were synthesized with a simple and cost-effective route at low temperature, and characterized by scanning electron microscopy, X-ray photoelectron spectroscopic spectrum, electrochemical impedance spectrum, UV-visible spectroscopy, Fourier transform infrared spectrum, and cyclic voltammetry, respectively. The results indicated that CaTiO3NPs exhibited large surface area, and greatly promoted the direct electron transfer between enzyme molecules and electrode surface. The immobilized enzymes on this matrix retained its native bioactivity and exhibited a surface controlled, quasi-reversible two-proton and two-electron transfer reaction with an electron transfer rate of 3.35 s−1. Using glucose oxidase as model, the prepared glucose biosensor showed a high sensitivity of 14.10±0.5 mA M−1 cm−2, a wide linear range of 7.0×10−6 to 1.49×10−3 M, and a low detection limit of 2.3×10−6 M at signal-to-noise of 3. Moreover, the biosensor also possessed good reproducibility, excellent selectivity and acceptable storage life. This research provided a new-type and promising perovskite nanomaterials for the development of efficient biosensors.