Abstract: Mg²⁺ is one of the important divalent metal ions in human body and plays an important role in the reactions of catalyzing nucleic acids in cells. The loss or excess of Mg²⁺ in human body can harm people’s health. At the same time,Mg²⁺ also has varied functions in the natural environment. Therefore,the detection of Mg²⁺ has received people’s attention,of which Mg²⁺ instrument detection technology has matured,but there are still some drawbacks. In recent years,functional nucleic acids have been uncovered to have the advantages of easy sequence modification,high specificity,high stability,low cost,and rapid detection on site with biosensors,and are attracting more and more attentions. Currently,a variety of specific Mg²⁺ functional nucleic acids biosensors have been established and the detections of various biomarkers are achieved. Meanwhile,the combination with novel nanomaterials further increases the detection limit and the broad spectrum of detection. This review first introduced the action and regularity mode,in vitro screening methods and structural properties of Mg²⁺ functional nucleic acids,and summarized the principles and applications of Mg²⁺ specific functional nucleic acid sensor. Secondly,based on the way of signal amplification and the combination with different nanomaterials,Mg²⁺ functional nucleic acid sensors are classified into temperature sensors,thermostatic sensors,gold nanosensors,and carbon nanosensors. The main content covers the sensing principles,application areas,sensitivities and detection limits of different sensors. Finally,the applications of Mg²⁺ functional nucleic acids in food and biomedicine are summarized and the existing problems and future applications are prospected,aiming at providing a theoretical basis for the future development of more portable,sensitive and accurate biosensors.

Key words: magnesium ion, functional nucleic acids, biosensor, gold nanosensor, carbon nanosensor