Fe₃O₄ Nanozymes with Aptamer-Tuned Catalysis for Selective Colorimetric Analysis of ATP in Blood

In this work, a simple and highly selective colorimetric method has been developed for quantifying trace-level ATP using Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). It was discovered that Fe 3 O 4 NPs could present the dramatically enhanced catalysis once anchored with ATP-specific aptamers (Apts), which is about 6-fold larger than that of bare Fe 3 O 4 NPs. In the presence of ATP, however, the Apts would be desorbed from Fe 3 O 4 NPs due to the Apts-target binding event, leading to the decrease of catalysis rationally depending on ATP concentrations. A colorimetric strategy was thereby developed to facilitate the highly selective detection of ATP, showing the linear concentrations ranging from 0.50 to 100 μM. Subsequently, the developed ATP sensor was employed for the evaluation of ATP in blood with the analysis performances comparably better than those of the documented detection methods, showing the potential applications in the clinical laboratory for the detective diagnosis of some ATP-indicative diseases. Importantly, such a catalysis-based detection strategy should be extended to other kinds of nanozymes with intrinsic catalysis properties (i.e., peroxidase and oxidase-like activities), promising as a universal candidate for monitoring various biological species simply by using target-specific recognition elements like Apts and antibodies.