Quicker, deeper and stronger imaging: A review of tumor-targeted, near-infrared fluorescent dyes for fluorescence guided surgery in the preclinical and clinical stages.

Cancer is a public health problem and the main cause of human mortality and morbidity worldwide. Complete removal of tumors and metastatic lymph nodes in surgery is significantly beneficial for the prognosis of patients. Tumor-targeted, near-infrared fluorescent (NIRF) imaging is an emerging field of real-time intraoperative cancer imaging based on tumor-targeted NIRF dyes. Targeted NIRF dyes contain NIRF fluorophores and specific binding ligands such as antibodies, peptides and small molecules. The present article reviews recently updated tumor-targeted NIRF dyes for the molecular imaging of malignant tumors in the preclinical stage and clinical trials. The strengths and challenges of NIRF agents with tumor-targeting ability are also summarized. Smaller ligands, near infrared II dyes, dual-modality dyes and activatable dyes may contribute to quicker, deeper, stronger imaging in the nearest future. In this review, we highlighted tumor-targeted NIRF dyes for fluorescence-guided surgery and their potential clinical translation.