Abstract:

Malignant tumors are common diseases that threaten human health. Early diagnosis and complete resection can significantly improve the prognosis of patients with malignant tumors. At present, the imaging techniques used clinically for malignant tumor detection have problems such as poor sensitivity and temporal-spatial resolution, long scanning time, etc., which cannot achieve early diagnosis and meet the requirements of surgical navigation. As a new imaging technology with excellent imaging characteristics, fluorescence imaging can perform real-time imaging of the structure and function of biological tissues and organs. It can realize the accurate detection of malignant tumors by designing fluorescent probes with high sensitivity, high selectivity and specificity. The sensitivity of fluorescence imaging mainly depends on the fluorophore of the probe, and the selectivity and specificity mainly depend on whether the probe adopts an effective targeting strategy. Studies have shown that near infrared fluorophores with emission wavelengths in the near infrared window, especially those in the near infrared Ⅱ window, have excellent optical properties, which can effectively improve the sensitivity of fluorescence imaging of malignant tumors; at the same time, based on the unique structure and metabolic features of malignant tumors, various targeting strategies have been developed to design "always-on" fluorescent probes and "turn-on" fluorescent probes, which significantly improved the selectivity and specificity of fluorescent imaging of malignant tumors. In this paper, the newly developed near infrared fluorophores and the strategies of fluorescent probes targeting malignant tumors are reviewed.

Key words: fluorescence imaging, malignant tumor, near infrared fluorophore, "always on" fluorescent probe, "turn on" fluorescent probe