FITC

FITC is a green fluorescein derivative. FITC is commonly used to label biomolecules such as antibodies, proteins, and nucleic acids. It can serve as a fluorescent probe for detecting cell viability, apoptosis, and other cellular processes. FITC has a maximum excitation wavelength of 494 nm and emits yellow-green fluorescence at its maximum emission wavelength of 520 nm.

Methods: P17 oxygen-induced retinal disease (OIR) mice received retro-orbital injections of FITC-dextran: 0.05 ml (50 mg/ml). Specimens were collected immediately post-injection. Fluorescence microscopy examined orbital tissues and retinas of the injected eye and contralateral eye.
Results: FITC-dextran was absorbed systemically, as demonstrated by bilateral retinal visualization following entry into the bloodstream via the orbital venous sinus.[1]

I. Amine labeling
1. Binding: Dilute FITC in an appropriate solvent (usually dimethylsulfonamide DMSO) and mix it with the target biomolecule solution. The reaction is usually carried out under slightly alkaline conditions (pH 8.0-9.0) to ensure effective binding of FITC.
2. Incubation: Incubate the mixture at room temperature or 4°C for 1-2 hours. Since FITC is light-sensitive, it needs to be protected from light.
3. Purification: After the reaction is completed, excess FITC is removed by purification techniques such as dialysis and gel filtration to obtain labeled biomolecules.
II. Cell imaging
1. Cell staining: Apply FITC-labeled antibodies or proteins to cells or tissues and incubate for a certain period of time (usually 30 minutes to 1 hour) at room temperature or 4°C.
2. Fluorescence microscopy: After washing away unbound antibodies, use a fluorescence microscope to observe cells or tissues. FITC can be excited at a wavelength of about 495 nm and emit at a wavelength of 519 nm.
III. pH and Cu2+ sensitivity
1. pH sensitivity: When FITC-labeled molecules are placed in solutions of different pH values, the fluorescence intensity will change with the change of pH and can be quantitatively measured.
2. Cu2+ detection: The fluorescence of FITC is also affected by Cu2+, so it can be used to determine the concentration of Cu2+ in the sample by observing the change of fluorescence intensity.

The above information is based on published literature. Experimental procedures should be appropriately modified to meet specific research demands.

DMSO: 250 mg/mL (642.05 mM), Sonication is recommended.