A review of current status of ratiometric molecularly imprinted electrochemical sensors: From design to applications

Electrochemical techniques have been demonstrated as powerful tools for various applications in analytical science. However, due to limited electrochemically active surface areas and poor anti-inference performance, their sensitivity and stability are weakened in real samples. By integrating electrochemical techniques with ratio-signal output modes and molecular imprinting polymers (MIPs), the newly constructed ratiometric molecularly imprinted electrochemical sensors (RMIECs) can outcompete conventional electrochemical techniques with higher sensitivity and stability, easier pretreatment, better selectivity and reproducibility, and are more adapted to complex environments. Fascinated by the superior performances of RMIECs, researchers from all research fields have been devoted to the design and development of RMIECs in different applications. For the first time, we summarize distinct ratiometric signal output modes and highlight four different types of RMIECs as well as their design, working principle and applications in analytical fields. In addition, the current challenges and prospects are carefully discussed to provide innovative idea tactics for developing new electrochemical methods.