FITC (Fluorescein 5-isothiocyanate) is a fluorescence probe for the labeling of amines. FITC is a pH- and Cu²⁺-sensitive fluorescence dye^[1][2].

Annexin V-FITC/PI is employed to detect chondrocyte apoptosis^[1]. The PEI-modified CDs are conjugated with fluorescein isothiocyanate (FITC) to fabricate CDs-FITC composites^[2].

389.38

Solid

C₂₁H₁₁NO₅S

3326-32-7

异硫氰酸荧光素酯；荧光素-5-异氰酸酯

Room temperature in continental US; may vary elsewhere.

-20°C, protect from light, stored under nitrogen

*In solvent : -80°C, 6 months; -20°C, 1 month (protect from light, stored under nitrogen)

DMSO : 50 mg/mL(128.41 mM;Need ultrasonic)

H₂O :< 0.1 mg/mL(insoluble)

请根据产品在不同溶剂中的溶解度选择合适的溶剂配制储备液；一旦配成溶液，请分装保存，避免反复冻融造成的产品失效。
储备液的保存方式和期限：-80℃, 6 months; -20℃, 1 month (protect from light, stored under nitrogen)。-80℃ 储存时，请在 6 个月内使用，-20℃ 储存时，请在 1 个月内使用。

请根据您的实验动物和给药方式选择适当的溶解方案。以下溶解方案都请先按照In Vitro方式配制澄清的储备液，再依次添加助溶剂：

——为保证实验结果的可靠性，澄清的储备液可以根据储存条件，适当保存；体内实验的工作液，建议您现用现配，当天使用； 以下溶剂前显示的百
分比是指该溶剂在您配制终溶液中的体积占比；如在配制过程中出现沉淀、析出现象，可以通过加热和/或超声的方式助溶

• 1.

  请依序添加每种溶剂： 10% DMSO    40%PEG300   5%Tween-80   45% saline

  Solubility: ≥ 2.08 mg/mL (5.34 mM); Clear solution

  此方案可获得 ≥ 2.08 mg/mL (5.34 mM，饱和度未知) 的澄清溶液。

  以 1 mL 工作液为例，取 100 μL 20.8 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀；向上述体系中加入50 μL Tween-80，混合均匀；然后继续加入 450 μL生理盐水定容至 1 mL。

  将 0.9 g 氯化钠，完全溶解于 100 mL ddH2O 中，得到澄清透明的生理盐水溶液
• 2.

  请依序添加每种溶剂： 10% DMSO    90% (20%SBE-β-CDin saline)

  Solubility: 2.08 mg/mL (5.34 mM); Suspended solution; Need ultrasonic

  此方案可获得 2.08 mg/mL (5.34 mM) 的均匀悬浊液，悬浊液可用于口服和腹腔注射。

  以 1 mL 工作液为例，取 100 μL 20.8 mg/mL 的澄清 DMSO 储备液加到 900 μL20% 的 SBE-β-CD 生理盐水水溶液中，混合均匀。

  将 2 g 磺丁基醚 β-环糊精加入 5 mL 生理盐水中，再用生理盐水定容至 10 mL，完全溶解，澄清透明

• 
  Description: FITC can be used as a fluorescence probe for nanocomposites with green fluorescence.
  Method: For nanocomposites linking.
  1. Add nanocomposite to EDC and NHS (molar ratio: 1:5:5), and the pH is adjusted to activate the carboxyl groups.
  2. Dissolve FITC in dimethyl sulfoxideab and add to the above mixture and shaked in the dark overnight.
  3. The final FITC-labeled nanocomposite is obtained by lyophilization.
  4. Use a probe-based confocal laser endoscopy (Cellvizio, Mauna Kea Technologies, France) for determination.
• 
  Description: FITC can be used as a fluorescence probe for nanocomposites with green fluorescence.
  Method: For nanocomposites linking.
  1. Suspend nanocomposites (20 mg) in PBS (20 mL) with FITC (1 mg) and put the mixture stirred overnight in the dark.
  2. Wash nanocomposites for five times with PBS to remove excess FITC.
  3. Testing cells are seeded into a 6-well microplate at a density of 10⁵/well and cultured overnight at 37℃ in 5% CO₂.
  4. Change the culture medium with as-prepared medium containing nanocomposite-FITC. After coincubation for 1, 2, 4, and 8 h, testing cells are rinsed three times with PBS.
  5. Use a confocal laser scanning microscopy ( FV1000 Olympus, Tokyo, Japan) for image.
• 
  Description: FITC can be used as a fluorescence probe for linking to molecule glue with green fluorescence.
• 
  Description: FITC can be used as a fluorescence probe for labeling lipophilic phytotoxin with green fluorescence.
• 
  Description: FITC can be used as a fluorescence probe for labeling laccase with green fluorescence.
  Method: For laccase labeling.
  1. FITC (1 mg/mL) solution is prepared with dimethyl sulfoxide.
  2. Dropwise add FITC into laccase solution (5 mg/mL), and stir the mixed solution at 4℃ for 4 h.
  3. Add NH₄Cl aqueous solution (2 mL, 50 mM) into the mixed solution to stop the reaction.
  4. Dialyze the solution in phosphate buffer (50 mM, pH 7) for 48 h at 4℃ to remove excess FITC.
  5. Use a confocal laser scanning microscopy (Leica SP8 STED 3X) for image.