A novel naphthofluorescein-based probe for ultrasensitive point-of-care testing of zinc(II) ions and its bioimaging in living cells and zebrafishes

The combination of fluorescence method with paper-based diagnostic device is quite suitable in point-of-care testing (POCT). Herein, we designed a novel hybrid fluorescein-based probe ZN-2 and investigated its fluorescent properties thoroughly in the detection of Zn2+. In comparison with the fluorescein-based probe ZN-1, ZN-2 displayed better sensitivity, long-wavelength and faster response to Zn2+ within 20 min. Interestingly, we could achieve ultrasensitive, high-throughput and visual detection in the POCT analysis of Zn2+ by anchoring this probe ZN-2 on the paper-based device. This device with satisfied performance for Zn2+ detection was achieved in real samples including cytochylema, serum and lake water. Finally, the probe ZN-2 was further applied to visualize and monitor the level changes of Zn2+ in the living cells and zebrafishes. (C) 2018 Elsevier B.V. All rights reserved.