Recent development and application of ratiometric electrochemical biosensor

As one kind of sensitive analysis devices, electrochemical biosensors (ECBSs) convert biological activities into quantifiable electrical signals depending on biological recognitions. Due to their simple operation, low background signal, high sensitivity and stable performance, ECBSs have attracted widespread attentions. However, majority of ECBSs adopt a single-signal output method, which may inevitably be affected by environment conditions and operating procedures, thus leading to inaccurate results. In order to overcome these issues, ratiometric electrochemical biosensors (RECBSs) have been explored. In RECBSs, internal reference substances are introduced to provide a built-in correction, which endow the biosensors with superior sensitivity and accuracy. This article reviews different types of RECBSs, as well as their latest applications in the detection of proteins, nucleic acids, small biomolecules and ions. In addition, major challenges in this field are outlined. Some suggestions for their developments in the future are also highlighted.