Cy5.5-SE  (Synonyms: Cyanine5.5 NHS ester)

Cy5.5-SE (Cyanine5.5 NHS ester) is a CY dye. CY, short for Cyanine, is a compound consisting of two nitrogen atoms connected by an odd number of methyl units. Cyanine compounds have the characteristics of long wavelength, adjustable absorption and emission, high extinction coefficient, good water solubility and relatively simple synthesis^[1]. CY dyes are of en used for the labeling of proteins, antibodies and small molecular compounds. For the labeling of protein antibodies, the combination can be completed through a simple mixing reaction. Below, we introduce the labeling method of protein antibody labeling, which has certain reference significance^[2]. Storage: protect from light.

Guide (The following is our recommended protocol. This protocol is only a guide and should be modified according to your specific needs).
1. Protein Preparation
To obtain the best labeling effect, please prepare the protein (antibody) concentration to 2 mg/mL.
1.1 The pH value of the protein solution should be 8.5 ± 0.5. If the pH is lower than 8.0, adjust it with 1 M sodium bicarbonate.
1.2 If the protein concentration is lower than 2 mg/mL, the labeling efficiency will be greatly reduced. To obtain the best labeling efficiency, it is recommended that the final protein concentration range be 2-10 mg/mL.
1.3 The protein must be in a buffer free of primary amines (such as Tris or glycine) and ammonium ions, otherwise the labeling efficiency will be affected.
2. Dye Preparation
Dilute the dye with anhydrous DMSO to prepare a clear stock solution of 10 mg/mL.
3. Calculation of Dye Amount
The amount of dye required for the reaction depends on the amount of protein to be labeled. The optimal molar ratio of dye to protein is approximately 10:1.
Example: Assuming the required labeled protein is 500 μL 2 mg/mL IgG (MW=150,000), and 1 mg of dye is dissolved in 100 μL DMSO, the required dye volume is 6.8 μL. The detailed calculation process is as follows:
1) mmol (IgG) = mg/mL (IgG) × mL (IgG)/MW (IgG) = 2 mg/mL × 0.5 mL/150,000 mg/mmol = 6.7 × 10^-6 mmol
2) mmol (dye) = mmol (IgG) × 10 = 6.7 × 10^-6 mmol × 10 = 6.7 × 10^-5 mmol
3) μL (dye) = mmol (dye) × MW (dye)/mg/μL (dye) = 6.7 ×10^-5 mmol ×1014.132 mg/mmol/0.01 mg/μL = 6.8 μL (dye)
Note: We recommend using a dye:protein molar ratio of 10:1. If the concentration is too low or too high, the ratio can be adjusted to 5:1, 15:1, or 20:1.
4. Running the Coupling Reaction
1) Slowly add the calculated volume of freshly prepared 10 mg/mL dye to 0.5 mL of protein sample solution, gently shake to mix, and then briefly centrifuge to collect the sample at the bottom of the reaction tube. Avoid vigorous mixing to prevent denaturation and inactivation of the protein sample.
2) Place the reaction tube in a dark place and incubate gently with shaking for 60 minutes at room temperature. Every 10-15 minutes, gently invert the reaction tube several times to thoroughly mix the reactants and improve labeling efficiency.
5. Purification of Conjugates
The following protocol is an example of purifying dye-protein conjugates using a Labelling Kits Centrifugation-Based Rapid Desalting Column (5KD) (HY-D3014).
5.1 Prepare the desalting column according to the instructions.
5.2 Load the reaction mixture onto the top of the desalting column.
5.3 Once the sample has run below the resin surface, immediately add PBS (pH 7.2-7.4).
5.4 Add more PBS (pH 7.2-7.4) to the target sample to complete column purification. Collect the fraction containing the desired dye-protein conjugate.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Cy5.5-labeled factor VIIa is developed for imagining cancer. Cy5.5 labeled with these targeting proteins specifically localize to the tumor xenografts for at least 14 days but unconjugated Cy5.5 does not localize to any xenografts or organs. This method of imaging anti-tissue factor in the tumor VECs may be useful in detecting primary tumors and metastases as well as monitoring in vivo therapeutic responses^[1]. pH/temperature sensitive magnetic nanogels conjugated with Cy5.5-labled lactoferrin (Cy5.5-Lf-MPNA nanogels) are developed as a promising contrast agent for preoperative MRI and intraoperative fluorescence imaging of glioma^[2].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

1014.13

C₄₅H₄₇N₃O₁₆S₄

442912-55-2

Solid

Light blue to blue

O=S(C1=CC(S(=O)([O-])=O)=C2C(C3=C([N+](CC)=C(/C=C/C=C/C=C4N(CCCCCC(ON5C(CCC5=O)=O)=O)C6=C(C7=CC(S(=O)(O)=O)=CC(S(=O)(O)=O)=C7C=C6)C/4(C)C)C3(C)C)C=C2)=C1)(O)=O

Room temperature in continental US; may vary elsewhere.

-20°C, sealed storage, away from moisture and light

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Zhu S, et al. Visualizing cancer and response to therapy in vivo using Cy5.5-labeled factor VIIa and anti-tissue factor antibody. J Drug Target. 2015 Apr;23(3):257-65.  [Content Brief]

  [2]. Ptaszek M. Rational design of fluorophores for in vivo applications. Prog Mol Biol Transl Sci. 2013;113:59-108.  [Content Brief]

  [3]. Shindy, H. A. (2017). Fundamentals in the chemistry of cyanine dyes: A review. Dyes and Pigments, 145, 505–513. doi:10.1016/j.dyepig.2017.06.029

  [4]. Jiang L, et al. pH/temperature sensitive magnetic nanogels conjugated with Cy5.5-labled lactoferrin for MR and fluorescence imaging of glioma in rats. Biomaterials. 2013 Oct;34(30):7418-28.  [Content Brief]

  [5]. Lim B, et al. A Unique Recombinant Fluoroprobe Targeting Activated Platelets Allows In Vivo Detection of Arterial Thrombosis and Pulmonary Embolism Using a Novel Three-Dimensional Fluorescence Emission Computed Tomography (FLECT) Technology. Theranostics. 2017 Feb 26;7(5):1047-1061.  [Content Brief]