A Highly Selective Mn(II)-Specific DNAzyme and Its Application in Intracellular Sensing

Manganese is an essential trace element in the humanbody thatacts as a cofactor in many enzymes and metabolisms. It is importantto develop methods to detect Mn2+ in living cells. Whilefluorescent sensors have been very effective in detecting other metalions, Mn2+-specific fluorescent sensors are rarely reporteddue to nonspecific fluorescence quenching by the paramagnetism ofMn(2+) and poor selectivity against other metal ions suchas Ca2+ and Mg2+. To address these issues, weherein report in vitro selection of an RNA-cleaving DNAzyme with exceptionallyhigh selectivity for Mn2+. Through converting it into afluorescent sensor using a catalytic beacon approach, Mn2+ sensing in immune cells and tumor cells has been achieved. The sensoris also used to monitor degradation of manganese-based nanomaterialssuch as MnOx in tumor cells. Therefore, this work provides an excellenttool to detect Mn2+ in biological systems and monitor theMn(2+)-involved immune response and antitumor therapy.

Automated summary

Manganese is an essential element in the human body and its detection in living cells is important. However, specific fluorescent sensors for Mn2+ are rare due to its paramagnetism and poor selectivity against other metal ions. This study reports the development of an RNA-cleaving DNAzyme with high selectivity for Mn2+ and its conversion into a fluorescent sensor. The sensor has been successfully used to detect Mn2+ in immune cells and tumor cells, as well as monitor the degradation of manganese-based nanomaterials in tumor cells.