Fluorescein (Solvent Yellow 94) is a phthalic indicator dye, use as a synthetic fluorescent tracer.

1. As a fluorescent tracer in tissue imaging
1. Material preparation:
1) Fluorescein solution: usually prepared as a 0.1%–1% solution, which can be dissolved in water, PBS or an appropriate buffer.
2) Tissue sample: biological tissue samples such as tumors, blood vessels or organs.
3) Fluorescence detection equipment: using a fluorescence microscope or imaging system, the excitation wavelength is 490 nm and the emission wavelength is 520 nm.
2. Steps:
1) Solution preparation: dissolve fluorescein in an appropriate solvent and prepare it to the required concentration.
2) Administration: Fluorescein solution can be injected (such as intravenous injection, subcutaneous injection) or applied topically into the organism or tissue.
3) Fluorescence imaging: after fluorescein is administered, it is distributed in the tissue or system, and then imaged using a fluorescence microscope or imaging system, usually using an excitation wavelength of 490 nm and an emission wavelength of 520 nm for detection.
4) Analysis: Analyze the distribution and localization of fluorescein in tissues. In cancer research, the selective uptake or retention of fluorescein by tumor tissue can help identify tumors.
2. Application of Fluorescein in Vascular Imaging
1. Material preparation:
1) Fluorescein solution: The commonly used sodium fluorescein solution is 10% concentration and is usually used for intravenous injection.
2) Imaging equipment: Use a fundus camera or fluorescent angiography system.
2. Steps:
1) Injection: Intravenous injection of fluorescein sodium.
2) Imaging: Use a fundus camera or angiography system to capture the fluorescent signal in the blood vessels. The system usually uses blue light to excite fluorescein and capture the yellow-green fluorescence emitted by the blood vessels.
3. Application of Fluorescein in Tumor Imaging
1. Material preparation:
1) Fluorescein solution: Prepare a fluorescein solution of appropriate concentration, usually dissolved in saline or PBS.
2) Tumor model: such as animal models with implanted tumors or clinical tumor samples.
2. Steps:
1) Administration: Inject fluorescein into tumor-bearing animals or human tumor tissue.
2) Imaging: Use fluorescence microscopy or other imaging techniques to observe the localization of fluorescein in the tumor. Tumor tissue usually exhibits bright green fluorescence due to the selective uptake of fluorescein.
Notes:
1) Toxicity: Although fluorescein is generally safe in clinical and research, there may be toxicity risks in the case of high doses or long-term exposure.
2) Photosensitivity: Fluorescein is sensitive to light and should be avoided from prolonged exposure to strong light to prevent photobleaching and dye degradation.
3) Dosage: The dose should be reasonably selected according to the experimental requirements to avoid excessive dye accumulation and ensure imaging effect.