Nanoporous Ce-Based Metal–Organic Framework Nanoparticles for NO Sensing

As a typical reactive nitrogen species, nitric oxide (NO) regulates various physiological processes in tissues. It is challenging to meet the requirements of low detection limit (a few nM) and wide detection range (larger than 1 μM) in detecting NO released from living cells. Herein, we prepare a nanoscale Ce-based metal–organic framework (CeMOF) biomimetic NO sensor, which obtains a high sensitivity (3.10 μA–1 μM–1 cm–2), a long detection range (6.00 nM to 312.67 μM), and a low detection limit (2.00 nM). Further, a CeMOF nanoparticle (NP) screen-printed electrode (SPE) chip is fabricated for cell adhesion and culture. By culturing cells on the surface, the CeMOF NPs/SPE achieves monitoring of NO molecules released from living HeLa and 293A cells. The Michaelis–Menten constant (Km) of the CeMOF biomimetic NO sensor is 1.3 nM, which indicates its excellent catalytic activity, which can be ascribed to the Ce coordination in CeMOF NPs to create high-density active catalytic centers for NO oxidation.