A new optical fiber sensor based on the CDs@UiO66 complex fluorescence probe for nitric oxide detection†

Nitric oxide (NO) is extensively involved in many physiological and pathological processes in biological systems and is of great significance in chemical and biomedical applications. Herein, a novel optical fiber NO sensor based on the carbon quantum dots (CDs)@UiO66 complex was prepared, in which CDs@UiO66 was encapsulated within cellulose acetate (CA) as a fluorescence probe to form the NO-sensitive film coated on the optical fiber end-face through a dip-coating method. The fluorescence properties and morphology of the CDs@UiO66 complex and its sensitive film were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, and contact angle tests. The fluorescence intensity response of the optical fiber sensor in detecting micromolar and nanomolar levels of NO was also investigated and showed a good linear dependence, while the lower limit of detection for NO reached 5 nM. Compared with other sensors, this new NO optical fiber sensor is simple to fabricate, is cost-effective, and has better selectivity, making it a potential candidate for NO detection.