Rapid and highly sensitive colloidal silver staining on cellulose acetate membrane for analysis of urinary proteins

In order to establish a rapid staining method sensitive enough to stain the protein bands on cellulose acetate membrane and suitable for the analysis of urinary proteins in healthy subjects, we conducted a detailed examination of Kovarik's method designed for the analysis of proteins in cerebrospinal fluid in detail. For purpose, of our study, we changed the pH of the staining solution used in Kovarik's method to pH 4.4 by adding acetic acid. With this solution, our staining method revealed a degree of sensitivity about three times higher than that of the original method, but specific sensitivity for albumin and gamma-globulin remained almost unchanged. The solution preparation we used was much more simple and the reagent much more stable than in the original method. Our method also showed better reproducibility and linearity than the original method. These results point to the suitability of this method for the analysis of low-concentration proteins, such as urinary proteins, in healthy subjects.