TSA Blocking Reagent (3 g)

To make TNB Blocking Buffer (for use in Tyramide Signal Amplification procedures):

• 0.1 M TRIS-HCl, pH 7.5
• 0.15 M NaCl
• 0.5% (w/v) Blocking reagent

Add Blocking Reagent slowly in small increments to buffer while stirring. Heat gradually to < 55ºC with continuous stirring to completely dissolve the Blocking Reagent. The solution will look milky. (This may take anywhere from 30 minutes to several hours. Preparation of volumes less than 100 mL allows for more even heating.) Bring to room temperature before using the blocking buffer. Aliquot and store at -20ºC for long term use. Discard any unused blocking buffer which has been stored for greater than 24 hours at room temperature.