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Buffers & Dyes
Cellular Dyes

DAPI #4083

Citations (6)
  1. IF
  2. F
Immunofluorescent analysis of HeLa cells using COX IV (3E11) Rabbit mAb #4850 (green), β-Catenin (L54E2) Mouse mAb (IF Preferred) #2677 (red) and DAPI (blue).
Immunofluorescent analysis of HUVE cells using VE-Cadherin (D87F2) XP® Rabbit mAb #2500 (green) and DAPI (blue). Actin filaments were labeled with DyLight 554 Phalloidin #13054 (red).
Flow cytometric analysis of Jurkat cells using Ki-67 (D3B5) Rabbit mAb (Alexa Fluor® 647 Conjugate) #12075 and DAPI (DNA content).

Product Usage Information

Directions for Use: DAPI is supplied as a lyophilized powder. For a 20 mg/ml stock, reconstitute the 1 mg in 50 µl deionized water or dimethylformamide. Please follow CST’s recommended IF and Flow protocols. For both applications, following secondary detection:

Immunofluorescence: Counterstain with DAPI as the final step in your staining procedure. Rinse samples twice in PBS for five min each. Dilute DAPI stock solution to a concentration between 1 - 0.1 µg/ml in PBS and incubate for 5 min at room temperature in the dark. Rinse samples once in PBS and then prepare for imaging. Examine immediately using appropriate excitation wavelength.

Alternatively, dilute DAPI stock solution to a concentration between 1 - 0.1 µg/ml in mounting media, apply to cells, and prepare for imaging. Examine immediately using appropriate excitation wavelength.

Flow Cytometry: Rinse samples once in Incubation Buffer. Dilute DAPI stock solution to a concentration between 1.60-0.400 µg/ml in PBS and incubate for 15 min at room temperature in the dark before analyzing cells on flow cytometer.


Store lyophilized or in solution at 4°C, desiccated. Protect from light. In lyophilized form, the chemical is stable for 24 months. Once in solution, use within 2-3 weeks to prevent loss of potency. For long-term storage, aliquot and store at -20°C to avoid multiple freeze/thaw cycles.

Fluorescent Properties

  • Free dye excitation maximum = 340 nm
  • Free dye emission maximum = 488 nm
  • DNA complex excitation maximum = 364 nm
  • DNA complex emission maximum = 454 nm

Product Description

DAPI is supplied as a lyophilized powder in 1 mg units. It can be used to examine cellular DNA in fluorescent microscopy and cytometry applications.
Molecular Formula C16H15N5 2(HCl)


4', 6-diamidino-2-phenylindole, dihydrochloride (DAPI) is a blue fluorescent DNA dye that targets double-stranded AT clusters in the DNA minor groove (1). One molecule of dye binds to each 3 base pairs of dsDNA and yields an approximate 20-fold fluorescent enhancement (2). The level of DAPI-DNA fluorescence is proportional to DNA content (3).

Limited Uses

Except as otherwise expressly agreed in a writing signed by a legally authorized representative of CST, the following terms apply to Products provided by CST, its affiliates or its distributors. Any Customer's terms and conditions that are in addition to, or different from, those contained herein, unless separately accepted in writing by a legally authorized representative of CST, are rejected and are of no force or effect.

Products are labeled with For Research Use Only or a similar labeling statement and have not been approved, cleared, or licensed by the FDA or other regulatory foreign or domestic entity, for any purpose. Customer shall not use any Product for any diagnostic or therapeutic purpose, or otherwise in any manner that conflicts with its labeling statement. Products sold or licensed by CST are provided for Customer as the end-user and solely for research and development uses. Any use of Product for diagnostic, prophylactic or therapeutic purposes, or any purchase of Product for resale (alone or as a component) or other commercial purpose, requires a separate license from CST. Customer shall (a) not sell, license, loan, donate or otherwise transfer or make available any Product to any third party, whether alone or in combination with other materials, or use the Products to manufacture any commercial products, (b) not copy, modify, reverse engineer, decompile, disassemble or otherwise attempt to discover the underlying structure or technology of the Products, or use the Products for the purpose of developing any products or services that would compete with CST products or services, (c) not alter or remove from the Products any trademarks, trade names, logos, patent or copyright notices or markings, (d) use the Products solely in accordance with CST Product Terms of Sale and any applicable documentation, and (e) comply with any license, terms of service or similar agreement with respect to any third party products or services used by Customer in connection with the Products.

For Research Use Only. Not for Use in Diagnostic Procedures.
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To Purchase # 4083
Cat. # Size Qty. Price
1 mg