METHYLENE BLUE STAIN
Cat. No. MB 119

Store at room temperature.
The product is stable for at least one year after the date of purchase.

PRODUCT DESCRIPTION
Methylene Blue Stain is an aqueous solution of methylene blue designed for quantitative or qualitative examination of RNA and DNA immobilized on hybridization membranes in northern, Southern and alkaline blotting. It can be used to verify the amount of RNA on hybridization membranes in northern blotting. Unlike the carcinogenic agent, ethidium bromide, Methylene Blue Stain does not intercalate in nucleic acid chains and accordingly, does not interfere with nucleic acid retention on hybridization membranes nor with the hybridization process (1). Methylene Blue Stain was tested and found applicable for use with both plastic and nitrocellulose membranes. However, the nitrocellulose membranes exhibited higher background staining.

STAINING PROTOCOL

1. Immobilize RNA or DNA on a hybridization membrane according to the manufacturer's directions.
2. Immerse the membrane (dry or wet) in Methylene Blue Stain and carry out staining for 5-10 minutes at room temperature.
3. Pour back Methylene Blue Stain into a bottle (the stain is reusable) and wash the membrane three times with water, each time gently shaking the membrane for 5-10 seconds.
4. RNA and DNA bands stain blue against the white to bluish background of the membrane.
   Methylene Blue Stain detects > 20 ng RNA or DNA/band.

QUANTITATION OF RNA OR DNA
Wet the membrane and a piece of blotting paper with water. Place the membrane on wet paper, photograph and use either a negative or positive for a densitometer scanning. For fast results, use Polaroid film type 667, 665 or 55.

Picture of Methylene Blue Stained Membrane

Total RNA (3 µg) and 0.24 - 9.5 Kb RNA ladder
transferred onto Nytran® membrane
and stained with Methylene Blue stain.

REFERENCE