9-Aminoacridine is a highly fluorescent anti-infective dye used clinically as a topical antiseptic and experimentally as a mutagen, due to its interaction with DNA. It is also used as an intracellular pH indicator.

I. Solution preparation
1. Preparation of stock solution: Dissolve it in DMSO (dimethylsulfonamide) or water to prepare the stock solution, usually at a concentration of 1-10mM. It can be adjusted according to actual conditions.
2. Preparation of working solution: Dilute it to an appropriate concentration with PBS/DMEM/H2O before use. The common working concentration is 1-10 μM, but the specific concentration should be optimized according to experimental requirements.
II. Cell labeling
1) Cell culture: Inoculate cells into appropriate culture dishes and culture to an appropriate density (e.g. 24 hours, the number of cells is 70%-80% density).
2) Labeling cells: Add a working concentration of 9-Aminoacridine solution to the cell culture medium. The general incubation time is 30 minutes to 1 hour, which can be adjusted according to experimental requirements.
3) Washing cells: After labeling, wash the cells thoroughly with PBS (phosphate buffered saline) to remove unbound 9-Aminoacridine.
4) Fluorescence detection:
Excitation and emission wavelengths: 9-Aminoacridine is excited at ex = 365 nm and emits fluorescence at em = 460 nm, producing bright blue fluorescence.
Fluorescence microscopy or flow cytometry: Use a suitable fluorescence microscope or flow cytometer for fluorescence detection to observe the fluorescence intensity in the cells.
Precautions:
1. Protect from light: 9-Aminoacridine is sensitive to light, especially when exposed to strong light, the fluorescence intensity will change. Avoid exposure to strong light when using it.
2. Solubility: It has different solubility in different solvents, and the solubility needs to be confirmed before use.
3. Cytotoxicity: Higher concentrations of 9-Aminoacridine may be toxic to cells, so the concentration should be optimized to avoid excessive cell toxicity.