Self-calibrating sensor with logic gate operation for anthrax biomarker based on nanoscaled bimetallic lanthanoid MOF

The bacillus anthracis is one of toxic bacterial spores that can cause human anthrax infections. In this effort, the nanoscaled bimetallic lanthanoid metal-organic framework (Ln-MOF), namely, [Tb0.43Eu1.57(1,4-phda)3(H2O)](H2O)2 was synthesized by tuning the mole ratio of Tb3+ and Eu3+ as a ratiometric luminescent sensor for anthrax biomarker (dipicolinic acid, DPA). The detection limits of this DPA sensor are as low as 5.9 nM in methanol and 0.17 μM in water which are lower than human infectious doses. This sensor can detect DPA via turn-on process with broad ranges at either low concentration (0−800 nM) in methanol or high concentration (20−100 μM) in an aqueous medium. Moreover, the bimetallic Ln-MOF’s emission colors in the presence of DPA are changed from red-orange to orange-yellow in methanol, and red-orange to green in water that can be easily seen in solution and film by naked-eyes. In addition, one-to-two logic gate operation for monitoring DPA concentration levels of this sensor has been developed. The luminescent probe is also applied for DPA detection in real tap-water and urine samples with good performances.