Methylene Blue: An FDA-Approved NIR-II Fluorogenic Probe with Extremely Low pH Responsibility for Hyperchlorhydria Imaging

• DOI: 10.1021/cbmi.4c00011
• Publication Date: 2024-04-13T02:14:00Z
• Authors: Guanjun Deng; Siwei Zhang; Xinghua Peng; Gongcheng Ma; Luxuan Liu; Yuyu Tan; Ping Gong; Ben Zhong Tang; Lintao Cai; Pengfei Zhang
• Keywords: Chemistry; Aggregation-induced emission; NIR-II fluorescence; Medical technology; Gastric hyperacidity; PH detection; R855-855.5; 540; FDA-approved; 530; QD1-999

Methylene blue (MB) is an FDA (Food and Drug Administration)-approved contrast agent with donor-acceptor (D-A) structure integrated with carbonyl-containing nitrogen-heterocycles. MB can be converted into MBH (protonated MB) by protonation, which not only induces the fluorescence emission red-shifted from the first near-infrared window (NIR-I, 650-950 nm) to the second near-infrared window (NIR-II, 1000-1700 nm) but also achieves ACQ-to-AIE conversion. MB has been successfully demonstrated in hyperacidemia imaging with an extremely low pH value (<1).