Fluorescent labeling is a widely used experimental method for tracking, detecting, and localizing a variety of biomolecules. Fluorescein-labeled sucrose is a common fluorescent marker that is commonly used in cell biology and drug delivery studies.
Three steps in the preparation of FITC fluorescein-labeled sucrose:
1 Pretreatment of fluorescein: Fluorescein (FITC) needs to be activated. Alkaline solution (e.g., NaOH) is usually used to dissolve fluorescein, and an appropriate amount of activator (e.g., DCC) is added to improve the activation efficiency. This step requires tight temperature and pH control to ensure a smooth activation reaction.
2: The activated fluorescein undergoes a coupling reaction with sucrose. Reaction conditions have a significant impact on the coupling efficiency, including temperature, pH, coupling agent concentration, and reaction time. In order to improve the coupling efficiency, the reaction is usually carried out under the protection of nitrogen to reduce the occurrence of side reactions.
3: The product is purified by dialysis or gel permeation chromatography to remove unreacted fluorescein and impurities. Purified FITC fluorescein-labeled sucrose needs to be quality tested to ensure that its purity and fluorescence intensity meet the experimental requirements.