Sensing ATP: Zeolitic Imidazolate Framework-67 Is Superior to Aptamers for Target Recognition

In a typical biosensor, a biomolecule such as an aptamer is used for target recognition, and a nanomaterial is used for signal generation. Herein, we communicate a reverse system using a nanomaterial for target recognition and a DNA for signaling. We discovered that a classic metal–organic framework material, zeolitic imidazolate framework (ZIF)-67, has ultrahigh selectivity for recognizing adenosine triphosphate (ATP), allowing a fluorescently labeled DNA oligonucleotide to be used for signal generation. This sensor showed up to a 24-fold increase in fluorescence upon adding 1 mM ATP, while the fluorescence increase after adding adenosine or guanosine triphosphate was less than twofold. Its selectivity is much better than that of the ATP aptamer, which binds adenosine even better. Using isothermal titration calorimetry, the selective binding of ATP was independently verified. This sensor has a detection limit of 29 nM ATP and it can even detect ATP in serum. By replacing Co2+ with Zn2+ to form ZIF-8 or by using CoO, the selectivity for ATP was lost. Therefore, by sophisticated material design, ultrahigh selectivity for molecular recognition can be achieved.