According to the procedure as little as 8 ng of the TMV protein is detectable with about 30 minutes exposure to the gold-labelled IgG. The reference also discloses that agents such as polyethylene glycol, polyvinylpyrrolidone and bovine serum albumin can enhance the stability of gold markers The use of Tween 20 to prevent nonspecific binding of protein on nitrocellulose is disclosed along with the