Sentence:  Following transfer, the PVDF membrane was removed from the transfer cassette and placed in a sandwich tray and incubated in 20ml <WSD>blotto</WSD> (1×tBST, 7% nonfat dry milk and 0.1% Tween-20 pH 7.4) for 1 h while rocking. 
Meaning of the word marked with <WSD> tags:  A reagent made from non-fat dry milk, phosphate buffered saline, and sodium azide, which is used to block protein binding sites for laboratory techniques such as blots and the enzyme-linked immunosorbent assay (ELISA).