Inlaid Nd-substituted bismuth titanate nanoplates for protein immobilization and Nd-controlled electrochemical properties

► Layered Bi4−xNdxTi3O12 nanoplates were synthesized by sol–gel hydrothermal strategy. ► Novel biosensors were explored through employing Bi4−xNdxTi3O12 nanoplates as the supporting medium. ► The electrochemical performance of the BNTO-x-based biosensors shows regularly variable with Nd-doping content. ► Compared with other BNTO-x-based biosensors, the BNTO-0.85-based biosensor has more excellent electrochemical properties. ► The work may open up a new idea for designing third-generation electrochemical biosensors. Neodymium (Nd) substituted bismuth titanate (Bi4−xNdxTi3O12, BNTO-x) nanoplates inlaid one another were prepared by sol–gel hydrothermal method, which was explored for protein immobilization and biosensor fabrication. Comparative experiments witnessed that Bi3+ ions in bismuth titanate (Bi4Ti3O12, BTO) were successfully substituted with Nd3+ ions, and the electrochemical properties of the Hb–Chi–BNTO biosensors closely depended on the Nd3+ ion content. With increasing the Nd3+ doping content, the electrochemical performance of the Hb–Chi–BNTO-x biosensors showed regularly variable. Moreover, compared with the Hb–Chi–BTO and other Hb–Chi–BNTO-x biosensors, the Hb–Chi–BNTO-0.85 biosensor had more excellent electrochemical and electrocatalytic properties such as stronger redox peak currents (approximately three-fold), smaller peak-to-peak separation (50mV), larger heterogeneous electron transfer rate (14.1±3.8s−1), higher surface concentration of electroactive redox protein (about 8.16×10−11mol/cm2), and better reproducibility and stability. The Nd-depended electrochemical properties of the Hb–Chi–BNTO biosensors may open up a new idea for designing third-generation electrochemical biosensors, and the BNTO-0.85-based biosensor is also expected to find potential applications in many areas such as biomedical, food, and environmental detection.