IR 813 perchlorate, a near-infrared (NIR) fluorescent dye (Ex=815 nm, Em=840 nm), is utilized for visualizing regional lymph nodes in mice [1].

IR 813 causes 31.4% hemolysis in red blood cells when applied at 17.3 μM for 2 hours, and induces 50% cell death in MRC-5 cells at 5.9 μM over 24 hours [1].

IR 813 perchlorate exhibits peak fluorescence intensity at 4 hours post-injection, accompanied by swift extravasation, when used to visualize regional lymph nodes in mice [1]. Ten-week-old female Balb/cOlaAnN mice are kept under a 12-hour light/dark cycle to minimize tissue autofluorescence in the NIR region, with free access to food and water. A single 5.1 nmol dose of IR 813 dye (20 µL of 0.173 mg/mL in a PEG-400/ethanol/water=3:2:5 solution) is injected subcutaneously into the right anterior paw. In vivo optical imaging is performed using the Fluobeam700 NIR system (739 nm excitation light at 3.5 mW, 750 nm long-pass emission cutoff filter) to record fluorescence intensity in the axillary lymph node (ALN) over a week (at 5 min, 1 h, 4 h, 24 h, and 7 days). Semiquantitative data are obtained from fluorescence images using ImageJ 1.44 software. [Following is our recommended protocol. This protocol only provides a guideline and should be modified according to your specific needs] [1].