A current-responsive HOF-functionalized micropipette sensor for highly sensitive Cu2+ detection

The fluctuation of copper ion (Cu 2+ ) content is closely related to the physiological state of the human body. Developing a facile and highly selective micropipette sensor to precisely monitor Cu 2+ content has become crucial for the diagnosis, treatment, and prognosis of diseases. Herein, we propose a hydrogen-bonded organic framework (HOF-101)-functionalized micropipette sensor, which enables highly sensitive and real-time detection of copper ions based on an ionic current-voltage response. This micropipette sensor is capable of detecting Cu 2+ in human serum with a remarkably low limit of detection (LOD) of 0.11 μM, while offering a broad dynamic detection range of 10 –1 –10 4 μM. The adsorption mechanism was elucidated through density functional theory (DFT) calculations, revealing the coordination effect and electrostatic interactions between Cu 2+ and the -COOH groups of HOF-101. This study not only fulfills the requirements of simple and sensitive detection of Cu 2+ , but also provides a new method for HOFs to detect ions in vivo.