Alizarin Red S sodium  (Synonyms: ARS sodium)

Alizarin Red S sodium is an anthraquinone derivative dye. When combined with cations such as calcium ions, the functional group of Alizarin Red S sodium can form a coordination bond with the cation through the oxygen atom to show orange-red fluorescence. Alizarin Red S sodium can be used for screening of calcium compounds in synovial fluid and detecting osteoblast differentiation, and can also be used for bone staining in mice. Excitation/emission wavelength: 500/570 nm^{[1][2][3][4][5]}.

Preparation of Alizarin Red S sodium^[1]
(1) Prepare a 2% aqueous solution of Alizarin Red S sodium.
(2) Use a pH meter to add ammonium hydroxide dropwise while stirring to adjust the pH to 4.2.
(3) Filter the solution through a 0.45 μm microfilter and store in an amber bottle.
(4) Refilter the solution through a 0.22 μm microfilter immediately before use.
Alizarin Red S sodium detection of osteoblast differentiation^[2]
(1) Induction of osteoblast differentiation: MC3T3-E1 cells were seeded in four-well plates at 1×10⁵ cells per well and cultured in α-MEM (without ascorbic acid) containing 10% fetal bovine serum. Osteoblast differentiation was induced using osteogenic medium (OSM) containing ascorbic acid (50 μg/mL) and β-glycerophospholipids (10 mM).
(2) Staining: MC3T3-E1 cells were washed with 1×PBS, fixed with 70% ethanol at room temperature for 10 min, rinsed with distilled water, and stained with Alizarin Red S for 10 min to detect calcium deposition in the matrix.
(3) Data analysis: The area of ​​the red zone is proportional to osteoblast differentiation.
Alizarin Red S sodium Screening test for calcium compounds in synovial fluid^[1]
(1) Synovial fluid preparation: Aspirate the synovial fluid into a disposable syringe and transfer the fluid to a clean test tube containing sodium heparin anticoagulant.
(2) Staining: Aspirate a drop of synovial fluid from the bottom of the test tube, place it on a clean slide, mix it with a drop of 2% Alizarin Red S, and cover it with a coverslip.
(3) Within three minutes of mixing, observe it under an ordinary light microscope and grade the degree of orange-red staining observed in each high-power field. The area of ​​the red area is proportional to the content of calcium compounds.

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

Alizarin Red S sodium staining of bones in vivo^[3]
(1) Rat treatment: 20% Alizarin Red S sodium (100 mg/kg, single dose) was injected into albino rats and the rats were killed 2 min-8 h after injection.
(2) Skull treatment: The rat skull was cut off and stored in 2% potassium hydroxide solution for several days. All soft tissues were removed, separated and rinsed in tap water, and stored in 80% ethanol. The skull was embedded in unsaturated polyester resin and cut into 50-60u sections in sagittal or frontal planes with a diamond saw.
(3) Microscopic examination: At 80 times magnification, bones emit green autofluorescence and Alizarin Red S sodium emits red fluorescence.

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

342.26

C₁₄H₇NaO₇S

130-22-3

Solid

Light yellow to brown

O=S(C(C=C1C2=O)=C(O)C(O)=C1C(C3=C2C=CC=C3)=O)(O[Na])=O

Room temperature in continental US; may vary elsewhere.

4°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.

* Note: If you choose water as the stock solution, please dilute it to the working solution, then filter and sterilize it with a 0.22 μm filter before use.

• [1]. H Paul, et al. Alizarin red S staining as a screening test to detect calcium compounds in synovial fluid. Arthritis Rheum. 1983 Feb;26(2):191-200.  [Content Brief]

  [2]. Soomin Lim, et al. Stimulatory Effects of KPR-A148 on Osteoblast Differentiation and Bone Regeneration. Tissue Eng Regen Med. 2019 Jul 17;16(4):405-413.  [Content Brief]

  [3]. H Vilmann, et al. The in vivo staining of bone with alizarin red S. J Anat. 1969 Nov;105(Pt 3):533-45.  [Content Brief]

  [4]. W Querido, et al. Giemsa as a fluorescent dye for mineralizing bone-like nodules in vitro. Biomed Mater. 2012 Feb;7(1):011001.  [Content Brief]

  [5]. Bo Lai, et al. Application of excitation and emission matrix fluorescence (EEM) and UV-vis absorption to monitor the characteristics of Alizarin Red S (ARS) during electro-Fenton degradation process. Chemosphere.2013 Nov;93(11):2805-13.  [Content Brief]