Direct red 254

Direct Red 254 is a bisazo dye for textile applications. Direct Red 254 can be used for amyloid tissue staining in basic research on neurodegenerative diseases (e.g., Alzheimer's disease)^[1][2]. In Vitro:Direct Red 254 (1% (w/v)) stains amyloid-like synthetic peptides and induces birefringence in vitro: some peptide fragments with amyloid-like properties (e.g., peptide fragment N14) exhibit green birefringence under polarized light after staining. This is a typical characteristic of amyloid deposits^[1].
Direct Red 254 can be effectively biodecolorized, and its decolorization efficiency is affected by its molecular structure and aggregation behavior in aqueous solution^[2].

Guide (The following is our recommended solution. This solution is merely a guideline and should be modified according to your specific needs.)
1. Solution Preparation
1.1 Direct Red 254 Staining Solution (0.1% w/v): Dissolve 0.1 g of Direct Red 254 in 100 mL of saturated picric acid aqueous solution. Stir until the powder is completely dissolved.
1.2 Acidified water: Mix 0.5 mL of glacial acetic acid with 100 mL of distilled water.
2. Staining Procedure
2.1 Preparation: Cultivate or attach the sample to a suitable substrate (such as a cover slip or glass plate).
2.2 Washing: Gently rinse the samples twice with phosphate-buffered saline (PBS).
2.3 Staining: Directly apply the Direct red 254 working solution onto the sample. The optimal concentration depends on your tissue type or detection parameters, but it is recommended to start from a range of 1 μM to 10 μM (diluted in serum-free medium or PBS).
2.4 Incubation: The samples are incubated at room temperature (in the dark) or at 37°C (for living cells, they need to be in a CO₂ incubator) for 15 to 60 minutes.
2.5 Washing: Rinse the samples three times with PBS (for 5 minutes each time) to remove any unbound dyes.